java/11 : java.base/javax/crypto/Cipher.java

Cipher
https://openjdk.java.net/
GPLv2 + Classpath Exception
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
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 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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package javax.crypto;

import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.regex.*;


import java.security.*;
import java.security.Provider.Service;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.InvalidParameterSpecException;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;

import javax.crypto.spec.*;

import java.nio.ByteBuffer;
import java.nio.ReadOnlyBufferException;

import sun.security.util.Debug;
import sun.security.jca.*;

This class provides the functionality of a cryptographic cipher for
encryption and decryption. It forms the core of the Java Cryptographic
Extension (JCE) framework.
In order to create a Cipher object, the application calls the Cipher's getInstance method, and passes the name of the requested transformation to it. Optionally, the name of a provider
may be specified.
A transformation is a string that describes the operation (or
set of operations) to be performed on the given input, to produce some
output. A transformation always includes the name of a cryptographic
algorithm (e.g., AES), and may be followed by a feedback mode and
padding scheme.
 A transformation is of the form:

"algorithm/mode/padding" or
"algorithm"

 (in the latter case,
provider-specific default values for the mode and padding scheme are used).
For example, the following is a valid transformation:
    Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
 Using modes such as CFB and OFB, block ciphers can encrypt data in units smaller than the cipher's actual block size. When requesting such a mode, you may optionally specify the number of bits to be processed at a time by appending this number to the mode name as shown in the "AES/CFB8/NoPadding" and "AES/OFB32/PKCS5Padding" transformations. If no such number is specified, a provider-specific default is used. (See the {@extLink security_guide_jdk_providers JDK Providers Documentation} for the JDK Providers default values.) Thus, block ciphers can be turned into byte-oriented stream ciphers by using an 8 bit mode such as CFB8 or OFB8. 
Modes such as Authenticated Encryption with Associated Data (AEAD)
provide authenticity assurances for both confidential data and
Additional Associated Data (AAD) that is not encrypted.  (Please see
 RFC 5116  for more information on AEAD and AAD algorithms such as GCM/CCM.) Both confidential and AAD data can be used when calculating the authentication tag (similar to a Mac). This tag is appended to the ciphertext during encryption, and is verified on decryption. 
 AEAD modes such as GCM/CCM perform all AAD authenticity calculations before starting the ciphertext authenticity calculations. To avoid implementations having to internally buffer ciphertext, all AAD data must be supplied to GCM/CCM implementations (via the updateAAD methods) before the ciphertext is processed (via the update and doFinal methods). 

Note that GCM mode has a uniqueness requirement on IVs used in
encryption with a given key. When IVs are repeated for GCM
encryption, such usages are subject to forgery attacks. Thus, after
each encryption operation using GCM mode, callers should re-initialize
the cipher objects with GCM parameters which have a different IV value.
    GCMParameterSpec s = ...;
    cipher.init(..., s);
    // If the GCM parameters were generated by the provider, it can
    // be retrieved by:
    // cipher.getParameters().getParameterSpec(GCMParameterSpec.class);
    cipher.updateAAD(...);  // AAD
    cipher.update(...);     // Multi-part update
    cipher.doFinal(...);    // conclusion of operation
    // Use a different IV value for every encryption
    byte[] newIv = ...;
    s = new GCMParameterSpec(s.getTLen(), newIv);
    cipher.init(..., s);
    ...

The ChaCha20 and ChaCha20-Poly1305 algorithms have a similar requirement
for unique nonces with a given key.  After each encryption or decryption
operation, callers should re-initialize their ChaCha20 or ChaCha20-Poly1305
ciphers with parameters that specify a different nonce value.  Please
see RFC 7539 for more
information on the ChaCha20 and ChaCha20-Poly1305 algorithms.
 Every implementation of the Java platform is required to support the following standard Cipher transformations with the keysizes in parentheses: 

AES/CBC/NoPadding (128)
AES/CBC/PKCS5Padding (128)
AES/ECB/NoPadding (128)
AES/ECB/PKCS5Padding (128)
AES/GCM/NoPadding (128)
DES/CBC/NoPadding (56)
DES/CBC/PKCS5Padding (56)
DES/ECB/NoPadding (56)
DES/ECB/PKCS5Padding (56)
DESede/CBC/NoPadding (168)
DESede/CBC/PKCS5Padding (168)
DESede/ECB/NoPadding (168)
DESede/ECB/PKCS5Padding (168)
RSA/ECB/PKCS1Padding (1024, 2048)
RSA/ECB/OAEPWithSHA-1AndMGF1Padding (1024, 2048)
RSA/ECB/OAEPWithSHA-256AndMGF1Padding (1024, 2048)

These transformations are described in the

Cipher section of the
Java Security Standard Algorithm Names Specification.
Consult the release documentation for your implementation to see if any
other transformations are supported.
Author: Jan Luehe
See Also: KeyGenerator
SecretKey
Since: 1.4/**
 * This class provides the functionality of a cryptographic cipher for
 * encryption and decryption. It forms the core of the Java Cryptographic
 * Extension (JCE) framework.
 *
 * <p>In order to create a Cipher object, the application calls the
 * Cipher's {@code getInstance} method, and passes the name of the
 * requested <i>transformation</i> to it. Optionally, the name of a provider
 * may be specified.
 *
 * <p>A <i>transformation</i> is a string that describes the operation (or
 * set of operations) to be performed on the given input, to produce some
 * output. A transformation always includes the name of a cryptographic
 * algorithm (e.g., <i>AES</i>), and may be followed by a feedback mode and
 * padding scheme.
 *
 * <p> A transformation is of the form:
 *
 * <ul>
 * <li>"<i>algorithm/mode/padding</i>" or
 *
 * <li>"<i>algorithm</i>"
 * </ul>
 *
 * <P> (in the latter case,
 * provider-specific default values for the mode and padding scheme are used).
 * For example, the following is a valid transformation:
 *
 * <pre>
 *     Cipher c = Cipher.getInstance("<i>AES/CBC/PKCS5Padding</i>");
 * </pre>
 *
 * Using modes such as {@code CFB} and {@code OFB}, block
 * ciphers can encrypt data in units smaller than the cipher's actual
 * block size.  When requesting such a mode, you may optionally specify
 * the number of bits to be processed at a time by appending this number
 * to the mode name as shown in the "{@code AES/CFB8/NoPadding}" and
 * "{@code AES/OFB32/PKCS5Padding}" transformations. If no such
 * number is specified, a provider-specific default is used.
 * (See the
 * {@extLink security_guide_jdk_providers JDK Providers Documentation}
 * for the JDK Providers default values.)
 * Thus, block ciphers can be turned into byte-oriented stream ciphers by
 * using an 8 bit mode such as CFB8 or OFB8.
 * <p>
 * Modes such as Authenticated Encryption with Associated Data (AEAD)
 * provide authenticity assurances for both confidential data and
 * Additional Associated Data (AAD) that is not encrypted.  (Please see
 * <a href="http://www.ietf.org/rfc/rfc5116.txt"> RFC 5116 </a> for more
 * information on AEAD and AAD algorithms such as GCM/CCM.) Both
 * confidential and AAD data can be used when calculating the
 * authentication tag (similar to a {@link Mac}).  This tag is appended
 * to the ciphertext during encryption, and is verified on decryption.
 * <p>
 * AEAD modes such as GCM/CCM perform all AAD authenticity calculations
 * before starting the ciphertext authenticity calculations.  To avoid
 * implementations having to internally buffer ciphertext, all AAD data
 * must be supplied to GCM/CCM implementations (via the {@code updateAAD}
 * methods) <b>before</b> the ciphertext is processed (via
 * the {@code update} and {@code doFinal} methods).
 * <p>
 * Note that GCM mode has a uniqueness requirement on IVs used in
 * encryption with a given key. When IVs are repeated for GCM
 * encryption, such usages are subject to forgery attacks. Thus, after
 * each encryption operation using GCM mode, callers should re-initialize
 * the cipher objects with GCM parameters which have a different IV value.
 * <pre>
 *     GCMParameterSpec s = ...;
 *     cipher.init(..., s);
 *
 *     // If the GCM parameters were generated by the provider, it can
 *     // be retrieved by:
 *     // cipher.getParameters().getParameterSpec(GCMParameterSpec.class);
 *
 *     cipher.updateAAD(...);  // AAD
 *     cipher.update(...);     // Multi-part update
 *     cipher.doFinal(...);    // conclusion of operation
 *
 *     // Use a different IV value for every encryption
 *     byte[] newIv = ...;
 *     s = new GCMParameterSpec(s.getTLen(), newIv);
 *     cipher.init(..., s);
 *     ...
 *
 * </pre>
 * The ChaCha20 and ChaCha20-Poly1305 algorithms have a similar requirement
 * for unique nonces with a given key.  After each encryption or decryption
 * operation, callers should re-initialize their ChaCha20 or ChaCha20-Poly1305
 * ciphers with parameters that specify a different nonce value.  Please
 * see <a href="https://tools.ietf.org/html/rfc7539">RFC 7539</a> for more
 * information on the ChaCha20 and ChaCha20-Poly1305 algorithms.
 * <p>
 * Every implementation of the Java platform is required to support
 * the following standard {@code Cipher} transformations with the keysizes
 * in parentheses:
 * <ul>
 * <li>{@code AES/CBC/NoPadding} (128)</li>
 * <li>{@code AES/CBC/PKCS5Padding} (128)</li>
 * <li>{@code AES/ECB/NoPadding} (128)</li>
 * <li>{@code AES/ECB/PKCS5Padding} (128)</li>
 * <li>{@code AES/GCM/NoPadding} (128)</li>
 * <li>{@code DES/CBC/NoPadding} (56)</li>
 * <li>{@code DES/CBC/PKCS5Padding} (56)</li>
 * <li>{@code DES/ECB/NoPadding} (56)</li>
 * <li>{@code DES/ECB/PKCS5Padding} (56)</li>
 * <li>{@code DESede/CBC/NoPadding} (168)</li>
 * <li>{@code DESede/CBC/PKCS5Padding} (168)</li>
 * <li>{@code DESede/ECB/NoPadding} (168)</li>
 * <li>{@code DESede/ECB/PKCS5Padding} (168)</li>
 * <li>{@code RSA/ECB/PKCS1Padding} (1024, 2048)</li>
 * <li>{@code RSA/ECB/OAEPWithSHA-1AndMGF1Padding} (1024, 2048)</li>
 * <li>{@code RSA/ECB/OAEPWithSHA-256AndMGF1Padding} (1024, 2048)</li>
 * </ul>
 * These transformations are described in the
 * <a href="{@docRoot}/../specs/security/standard-names.html#cipher-algorithm-names">
 * Cipher section</a> of the
 * Java Security Standard Algorithm Names Specification.
 * Consult the release documentation for your implementation to see if any
 * other transformations are supported.
 *
 * @author Jan Luehe
 * @see KeyGenerator
 * @see SecretKey
 * @since 1.4
 */

public class Cipher {

    private static final Debug debug =
                        Debug.getInstance("jca", "Cipher");

    private static final Debug pdebug =
                        Debug.getInstance("provider", "Provider");
    private static final boolean skipDebug =
        Debug.isOn("engine=") && !Debug.isOn("cipher");

    Constant used to initialize cipher to encryption mode.
/**
     * Constant used to initialize cipher to encryption mode.
     */
    public static final int ENCRYPT_MODE = 1;

    Constant used to initialize cipher to decryption mode.
/**
     * Constant used to initialize cipher to decryption mode.
     */
    public static final int DECRYPT_MODE = 2;

    Constant used to initialize cipher to key-wrapping mode.
/**
     * Constant used to initialize cipher to key-wrapping mode.
     */
    public static final int WRAP_MODE = 3;

    Constant used to initialize cipher to key-unwrapping mode.
/**
     * Constant used to initialize cipher to key-unwrapping mode.
     */
    public static final int UNWRAP_MODE = 4;

    Constant used to indicate the to-be-unwrapped key is a "public key".
/**
     * Constant used to indicate the to-be-unwrapped key is a "public key".
     */
    public static final int PUBLIC_KEY = 1;

    Constant used to indicate the to-be-unwrapped key is a "private key".
/**
     * Constant used to indicate the to-be-unwrapped key is a "private key".
     */
    public static final int PRIVATE_KEY = 2;

    Constant used to indicate the to-be-unwrapped key is a "secret key".
/**
     * Constant used to indicate the to-be-unwrapped key is a "secret key".
     */
    public static final int SECRET_KEY = 3;

    // The provider
    private Provider provider;

    // The provider implementation (delegate)
    private CipherSpi spi;

    // The transformation
    private String transformation;

    // Crypto permission representing the maximum allowable cryptographic
    // strength that this Cipher object can be used for. (The cryptographic
    // strength is a function of the keysize and algorithm parameters encoded
    // in the crypto permission.)
    private CryptoPermission cryptoPerm;

    // The exemption mechanism that needs to be enforced
    private ExemptionMechanism exmech;

    // Flag which indicates whether or not this cipher has been initialized
    private boolean initialized = false;

    // The operation mode - store the operation mode after the
    // cipher has been initialized.
    private int opmode = 0;

    // The OID for the KeyUsage extension in an X.509 v3 certificate
    private static final String KEY_USAGE_EXTENSION_OID = "2.5.29.15";

    // next SPI  to try in provider selection
    // null once provider is selected
    private CipherSpi firstSpi;

    // next service to try in provider selection
    // null once provider is selected
    private Service firstService;

    // remaining services to try in provider selection
    // null once provider is selected
    private Iterator<Service> serviceIterator;

    // list of transform Strings to lookup in the provider
    private List<Transform> transforms;

    private final Object lock;

    Creates a Cipher object.
Params: cipherSpi – the delegate
provider – the provider
transformation – the transformation/**
     * Creates a Cipher object.
     *
     * @param cipherSpi the delegate
     * @param provider the provider
     * @param transformation the transformation
     */
    protected Cipher(CipherSpi cipherSpi,
                     Provider provider,
                     String transformation) {
        // See bug 4341369 & 4334690 for more info.
        // If the caller is trusted, then okay.
        // Otherwise throw a NullPointerException.
        if (!JceSecurityManager.INSTANCE.isCallerTrusted(provider)) {
            throw new NullPointerException();
        }
        this.spi = cipherSpi;
        this.provider = provider;
        this.transformation = transformation;
        this.cryptoPerm = CryptoAllPermission.INSTANCE;
        this.lock = null;
    }

    Creates a Cipher object. Called internally and by NullCipher.
Params: cipherSpi – the delegate
transformation – the transformation/**
     * Creates a Cipher object. Called internally and by NullCipher.
     *
     * @param cipherSpi the delegate
     * @param transformation the transformation
     */
    Cipher(CipherSpi cipherSpi, String transformation) {
        this.spi = cipherSpi;
        this.transformation = transformation;
        this.cryptoPerm = CryptoAllPermission.INSTANCE;
        this.lock = null;
    }

    private Cipher(CipherSpi firstSpi, Service firstService,
            Iterator<Service> serviceIterator, String transformation,
            List<Transform> transforms) {
        this.firstSpi = firstSpi;
        this.firstService = firstService;
        this.serviceIterator = serviceIterator;
        this.transforms = transforms;
        this.transformation = transformation;
        this.lock = new Object();
    }

    private static String[] tokenizeTransformation(String transformation)
            throws NoSuchAlgorithmException {
        if (transformation == null) {
            throw new NoSuchAlgorithmException("No transformation given");
        }
        /*
         * array containing the components of a Cipher transformation:
         *
         * index 0: algorithm component (e.g., AES)
         * index 1: feedback component (e.g., CFB)
         * index 2: padding component (e.g., PKCS5Padding)
         */
        String[] parts = new String[3];
        int count = 0;
        StringTokenizer parser = new StringTokenizer(transformation, "/");
        try {
            while (parser.hasMoreTokens() && count < 3) {
                parts[count++] = parser.nextToken().trim();
            }
            if (count == 0 || count == 2) {
                throw new NoSuchAlgorithmException("Invalid transformation"
                                               + " format:" +
                                               transformation);
            }
            // treats all subsequent tokens as part of padding
            if (count == 3 && parser.hasMoreTokens()) {
                parts[2] = parts[2] + parser.nextToken("\r\n");
            }
        } catch (NoSuchElementException e) {
            throw new NoSuchAlgorithmException("Invalid transformation " +
                                           "format:" + transformation);
        }
        if ((parts[0] == null) || (parts[0].isEmpty())) {
            throw new NoSuchAlgorithmException("Invalid transformation:" +
                                   "algorithm not specified-"
                                   + transformation);
        }
        return parts;
    }

    // Provider attribute name for supported chaining mode
    private static final String ATTR_MODE = "SupportedModes";
    // Provider attribute name for supported padding names
    private static final String ATTR_PAD  = "SupportedPaddings";

    // constants indicating whether the provider supports
    // a given mode or padding
    private static final int S_NO    = 0;       // does not support
    private static final int S_MAYBE = 1;       // unable to determine
    private static final int S_YES   = 2;       // does support

    Nested class to deal with modes and paddings.
/**
     * Nested class to deal with modes and paddings.
     */
    private static class Transform {
        // transform string to lookup in the provider
        final String transform;
        // the mode/padding suffix in upper case. for example, if the algorithm
        // to lookup is "AES/CBC/PKCS5Padding" suffix is "/CBC/PKCS5PADDING"
        // if lookup is "AES", suffix is the empty string
        // needed because aliases prevent straight transform.equals()
        final String suffix;
        // value to pass to setMode() or null if no such call required
        final String mode;
        // value to pass to setPadding() or null if no such call required
        final String pad;
        Transform(String alg, String suffix, String mode, String pad) {
            this.transform = alg + suffix;
            this.suffix = suffix.toUpperCase(Locale.ENGLISH);
            this.mode = mode;
            this.pad = pad;
        }
        // set mode and padding for the given SPI
        void setModePadding(CipherSpi spi) throws NoSuchAlgorithmException,
                NoSuchPaddingException {
            if (mode != null) {
                spi.engineSetMode(mode);
            }
            if (pad != null) {
                spi.engineSetPadding(pad);
            }
        }
        // check whether the given services supports the mode and
        // padding described by this Transform
        int supportsModePadding(Service s) {
            int smode = supportsMode(s);
            if (smode == S_NO) {
                return smode;
            }
            int spad = supportsPadding(s);
            // our constants are defined so that Math.min() is a tri-valued AND
            return Math.min(smode, spad);
        }

        // separate methods for mode and padding
        // called directly by Cipher only to throw the correct exception
        int supportsMode(Service s) {
            return supports(s, ATTR_MODE, mode);
        }
        int supportsPadding(Service s) {
            return supports(s, ATTR_PAD, pad);
        }

        private static int supports(Service s, String attrName, String value) {
            if (value == null) {
                return S_YES;
            }
            String regexp = s.getAttribute(attrName);
            if (regexp == null) {
                return S_MAYBE;
            }
            return matches(regexp, value) ? S_YES : S_NO;
        }

        // ConcurrentMap<String,Pattern> for previously compiled patterns
        private static final ConcurrentMap<String, Pattern> patternCache =
            new ConcurrentHashMap<String, Pattern>();

        private static boolean matches(String regexp, String str) {
            Pattern pattern = patternCache.get(regexp);
            if (pattern == null) {
                pattern = Pattern.compile(regexp);
                patternCache.putIfAbsent(regexp, pattern);
            }
            return pattern.matcher(str.toUpperCase(Locale.ENGLISH)).matches();
        }

    }

    private static List<Transform> getTransforms(String transformation)
            throws NoSuchAlgorithmException {
        String[] parts = tokenizeTransformation(transformation);

        String alg = parts[0];
        String mode = parts[1];
        String pad = parts[2];
        if ((mode != null) && (mode.isEmpty())) {
            mode = null;
        }
        if ((pad != null) && (pad.isEmpty())) {
            pad = null;
        }

        if ((mode == null) && (pad == null)) {
            // AES
            Transform tr = new Transform(alg, "", null, null);
            return Collections.singletonList(tr);
        } else { // if ((mode != null) && (pad != null)) {
            // AES/CBC/PKCS5Padding
            List<Transform> list = new ArrayList<>(4);
            list.add(new Transform(alg, "/" + mode + "/" + pad, null, null));
            list.add(new Transform(alg, "/" + mode, null, pad));
            list.add(new Transform(alg, "//" + pad, mode, null));
            list.add(new Transform(alg, "", mode, pad));
            return list;
        }
    }

    // get the transform matching the specified service
    private static Transform getTransform(Service s,
                                          List<Transform> transforms) {
        String alg = s.getAlgorithm().toUpperCase(Locale.ENGLISH);
        for (Transform tr : transforms) {
            if (alg.endsWith(tr.suffix)) {
                return tr;
            }
        }
        return null;
    }

    Returns a Cipher object that implements the specified transformation.  This method traverses the list of registered security Providers,
starting with the most preferred Provider.
A new Cipher object encapsulating the
CipherSpi implementation from the first
Provider that supports the specified algorithm is returned.
 Note that the list of registered providers may be retrieved via the Security.getProviders() method. 
Params: transformation – the name of the transformation, e.g.,
AES/CBC/PKCS5Padding.
See the Cipher section in the 
Java Security Standard Algorithm Names Specification
for information about standard transformation names.
Throws: NoSuchAlgorithmException – if transformation is null, empty, in an invalid format, or if no Provider supports a CipherSpi implementation for the specified algorithm
NoSuchPaddingException – if transformation contains a padding scheme that is not available
See Also: Provider
Implementation Note:  The JDK Reference Implementation additionally uses the jdk.security.provider.preferred Security property to determine the preferred provider order for the specified algorithm. This may be different than the order of providers returned by Security.getProviders().
Returns: a cipher that implements the requested transformation/**
     * Returns a {@code Cipher} object that implements the specified
     * transformation.
     *
     * <p> This method traverses the list of registered security Providers,
     * starting with the most preferred Provider.
     * A new Cipher object encapsulating the
     * CipherSpi implementation from the first
     * Provider that supports the specified algorithm is returned.
     *
     * <p> Note that the list of registered providers may be retrieved via
     * the {@link Security#getProviders() Security.getProviders()} method.
     *
     * @implNote
     * The JDK Reference Implementation additionally uses the
     * {@code jdk.security.provider.preferred}
     * {@link Security#getProperty(String) Security} property to determine
     * the preferred provider order for the specified algorithm. This
     * may be different than the order of providers returned by
     * {@link Security#getProviders() Security.getProviders()}.
     *
     * @param transformation the name of the transformation, e.g.,
     * <i>AES/CBC/PKCS5Padding</i>.
     * See the Cipher section in the <a href=
     *   "{@docRoot}/../specs/security/standard-names.html#cipher-algorithm-names">
     * Java Security Standard Algorithm Names Specification</a>
     * for information about standard transformation names.
     *
     * @return a cipher that implements the requested transformation
     *
     * @throws NoSuchAlgorithmException if {@code transformation}
     *         is {@code null}, empty, in an invalid format,
     *         or if no {@code Provider} supports a {@code CipherSpi}
     *         implementation for the specified algorithm
     *
     * @throws NoSuchPaddingException if {@code transformation}
     *         contains a padding scheme that is not available
     *
     * @see java.security.Provider
     */
    public static final Cipher getInstance(String transformation)
            throws NoSuchAlgorithmException, NoSuchPaddingException
    {
        if ((transformation == null) || transformation.equals("")) {
            throw new NoSuchAlgorithmException("Null or empty transformation");
        }
        List<Transform> transforms = getTransforms(transformation);
        List<ServiceId> cipherServices = new ArrayList<>(transforms.size());
        for (Transform transform : transforms) {
            cipherServices.add(new ServiceId("Cipher", transform.transform));
        }
        List<Service> services = GetInstance.getServices(cipherServices);
        // make sure there is at least one service from a signed provider
        // and that it can use the specified mode and padding
        Iterator<Service> t = services.iterator();
        Exception failure = null;
        while (t.hasNext()) {
            Service s = t.next();
            if (JceSecurity.canUseProvider(s.getProvider()) == false) {
                continue;
            }
            Transform tr = getTransform(s, transforms);
            if (tr == null) {
                // should never happen
                continue;
            }
            int canuse = tr.supportsModePadding(s);
            if (canuse == S_NO) {
                // does not support mode or padding we need, ignore
                continue;
            }
            if (canuse == S_YES) {
                return new Cipher(null, s, t, transformation, transforms);
            } else { // S_MAYBE, try out if it works
                try {
                    CipherSpi spi = (CipherSpi)s.newInstance(null);
                    tr.setModePadding(spi);
                    return new Cipher(spi, s, t, transformation, transforms);
                } catch (Exception e) {
                    failure = e;
                }
            }
        }
        throw new NoSuchAlgorithmException
            ("Cannot find any provider supporting " + transformation, failure);
    }

    Returns a Cipher object that implements the specified transformation.  A new Cipher object encapsulating the
CipherSpi implementation from the specified provider
is returned.  The specified provider must be registered
in the security provider list.
 Note that the list of registered providers may be retrieved via the Security.getProviders() method. 
Params: transformation – the name of the transformation,
e.g., AES/CBC/PKCS5Padding.
See the Cipher section in the 
Java Security Standard Algorithm Names Specification
for information about standard transformation names.
provider – the name of the provider.
Throws: IllegalArgumentException – if the provider is null or empty
NoSuchAlgorithmException – if transformation is null, empty, in an invalid format, or if a CipherSpi implementation for the specified algorithm is not available from the specified provider
NoSuchPaddingException – if transformation contains a padding scheme that is not available
NoSuchProviderException – if the specified provider is not
        registered in the security provider list
See Also: Provider
Returns: a cipher that implements the requested transformation/**
     * Returns a {@code Cipher} object that implements the specified
     * transformation.
     *
     * <p> A new Cipher object encapsulating the
     * CipherSpi implementation from the specified provider
     * is returned.  The specified provider must be registered
     * in the security provider list.
     *
     * <p> Note that the list of registered providers may be retrieved via
     * the {@link Security#getProviders() Security.getProviders()} method.
     *
     * @param transformation the name of the transformation,
     * e.g., <i>AES/CBC/PKCS5Padding</i>.
     * See the Cipher section in the <a href=
     *   "{@docRoot}/../specs/security/standard-names.html#cipher-algorithm-names">
     * Java Security Standard Algorithm Names Specification</a>
     * for information about standard transformation names.
     *
     * @param provider the name of the provider.
     *
     * @return a cipher that implements the requested transformation
     *
     * @throws IllegalArgumentException if the {@code provider}
     *         is {@code null} or empty
     *
     * @throws NoSuchAlgorithmException if {@code transformation}
     *         is {@code null}, empty, in an invalid format,
     *         or if a {@code CipherSpi} implementation for the
     *         specified algorithm is not available from the specified
     *         provider
     *
     * @throws NoSuchPaddingException if {@code transformation}
     *         contains a padding scheme that is not available
     *
     * @throws NoSuchProviderException if the specified provider is not
     *         registered in the security provider list
     *
     * @see java.security.Provider
     */
    public static final Cipher getInstance(String transformation,
                                           String provider)
            throws NoSuchAlgorithmException, NoSuchProviderException,
            NoSuchPaddingException
    {
        if ((transformation == null) || transformation.equals("")) {
            throw new NoSuchAlgorithmException("Null or empty transformation");
        }
        if ((provider == null) || (provider.isEmpty())) {
            throw new IllegalArgumentException("Missing provider");
        }
        Provider p = Security.getProvider(provider);
        if (p == null) {
            throw new NoSuchProviderException("No such provider: " +
                                              provider);
        }
        return getInstance(transformation, p);
    }

    private String getProviderName() {
        return (provider == null)  ? "(no provider)" : provider.getName();
    }

    Returns a Cipher object that implements the specified transformation.  A new Cipher object encapsulating the
CipherSpi implementation from the specified Provider
object is returned.  Note that the specified Provider object
does not have to be registered in the provider list.
Params: transformation – the name of the transformation,
e.g., AES/CBC/PKCS5Padding.
See the Cipher section in the 
Java Security Standard Algorithm Names Specification
for information about standard transformation names.
provider – the provider.
Throws: IllegalArgumentException – if the provider is null
NoSuchAlgorithmException – if transformation is null, empty, in an invalid format, or if a CipherSpi implementation for the specified algorithm is not available from the specified Provider object
NoSuchPaddingException – if transformation contains a padding scheme that is not available
See Also: Provider
Returns: a cipher that implements the requested transformation/**
     * Returns a {@code Cipher} object that implements the specified
     * transformation.
     *
     * <p> A new Cipher object encapsulating the
     * CipherSpi implementation from the specified Provider
     * object is returned.  Note that the specified Provider object
     * does not have to be registered in the provider list.
     *
     * @param transformation the name of the transformation,
     * e.g., <i>AES/CBC/PKCS5Padding</i>.
     * See the Cipher section in the <a href=
     *   "{@docRoot}/../specs/security/standard-names.html#cipher-algorithm-names">
     * Java Security Standard Algorithm Names Specification</a>
     * for information about standard transformation names.
     *
     * @param provider the provider.
     *
     * @return a cipher that implements the requested transformation
     *
     * @throws IllegalArgumentException if the {@code provider}
     *         is {@code null}
     *
     * @throws NoSuchAlgorithmException if {@code transformation}
     *         is {@code null}, empty, in an invalid format,
     *         or if a {@code CipherSpi} implementation for the
     *         specified algorithm is not available from the specified
     *         {@code Provider} object
     *
     * @throws NoSuchPaddingException if {@code transformation}
     *         contains a padding scheme that is not available
     *
     * @see java.security.Provider
     */
    public static final Cipher getInstance(String transformation,
                                           Provider provider)
            throws NoSuchAlgorithmException, NoSuchPaddingException
    {
        if ((transformation == null) || transformation.equals("")) {
            throw new NoSuchAlgorithmException("Null or empty transformation");
        }
        if (provider == null) {
            throw new IllegalArgumentException("Missing provider");
        }
        Exception failure = null;
        List<Transform> transforms = getTransforms(transformation);
        boolean providerChecked = false;
        String paddingError = null;
        for (Transform tr : transforms) {
            Service s = provider.getService("Cipher", tr.transform);
            if (s == null) {
                continue;
            }
            if (providerChecked == false) {
                // for compatibility, first do the lookup and then verify
                // the provider. this makes the difference between a NSAE
                // and a SecurityException if the
                // provider does not support the algorithm.
                Exception ve = JceSecurity.getVerificationResult(provider);
                if (ve != null) {
                    String msg = "JCE cannot authenticate the provider "
                        + provider.getName();
                    throw new SecurityException(msg, ve);
                }
                providerChecked = true;
            }
            if (tr.supportsMode(s) == S_NO) {
                continue;
            }
            if (tr.supportsPadding(s) == S_NO) {
                paddingError = tr.pad;
                continue;
            }
            try {
                CipherSpi spi = (CipherSpi)s.newInstance(null);
                tr.setModePadding(spi);
                Cipher cipher = new Cipher(spi, transformation);
                cipher.provider = s.getProvider();
                cipher.initCryptoPermission();
                return cipher;
            } catch (Exception e) {
                failure = e;
            }
        }

        // throw NoSuchPaddingException if the problem is with padding
        if (failure instanceof NoSuchPaddingException) {
            throw (NoSuchPaddingException)failure;
        }
        if (paddingError != null) {
            throw new NoSuchPaddingException
                ("Padding not supported: " + paddingError);
        }
        throw new NoSuchAlgorithmException
                ("No such algorithm: " + transformation, failure);
    }

    // If the requested crypto service is export-controlled,
    // determine the maximum allowable keysize.
    private void initCryptoPermission() throws NoSuchAlgorithmException {
        if (JceSecurity.isRestricted() == false) {
            cryptoPerm = CryptoAllPermission.INSTANCE;
            exmech = null;
            return;
        }
        cryptoPerm = getConfiguredPermission(transformation);
        // Instantiate the exemption mechanism (if required)
        String exmechName = cryptoPerm.getExemptionMechanism();
        if (exmechName != null) {
            exmech = ExemptionMechanism.getInstance(exmechName);
        }
    }

    // max number of debug warnings to print from chooseFirstProvider()
    private static int warnCount = 10;

    Choose the Spi from the first provider available. Used if
delayed provider selection is not possible because init()
is not the first method called.
/**
     * Choose the Spi from the first provider available. Used if
     * delayed provider selection is not possible because init()
     * is not the first method called.
     */
    void chooseFirstProvider() {
        if (spi != null) {
            return;
        }
        synchronized (lock) {
            if (spi != null) {
                return;
            }
            if (debug != null) {
                int w = --warnCount;
                if (w >= 0) {
                    debug.println("Cipher.init() not first method "
                        + "called, disabling delayed provider selection");
                    if (w == 0) {
                        debug.println("Further warnings of this type will "
                            + "be suppressed");
                    }
                    new Exception("Call trace").printStackTrace();
                }
            }
            Exception lastException = null;
            while ((firstService != null) || serviceIterator.hasNext()) {
                Service s;
                CipherSpi thisSpi;
                if (firstService != null) {
                    s = firstService;
                    thisSpi = firstSpi;
                    firstService = null;
                    firstSpi = null;
                } else {
                    s = serviceIterator.next();
                    thisSpi = null;
                }
                if (JceSecurity.canUseProvider(s.getProvider()) == false) {
                    continue;
                }
                Transform tr = getTransform(s, transforms);
                if (tr == null) {
                    // should never happen
                    continue;
                }
                if (tr.supportsModePadding(s) == S_NO) {
                    continue;
                }
                try {
                    if (thisSpi == null) {
                        Object obj = s.newInstance(null);
                        if (obj instanceof CipherSpi == false) {
                            continue;
                        }
                        thisSpi = (CipherSpi)obj;
                    }
                    tr.setModePadding(thisSpi);
                    initCryptoPermission();
                    spi = thisSpi;
                    provider = s.getProvider();
                    // not needed any more
                    firstService = null;
                    serviceIterator = null;
                    transforms = null;
                    return;
                } catch (Exception e) {
                    lastException = e;
                }
            }
            ProviderException e = new ProviderException
                    ("Could not construct CipherSpi instance");
            if (lastException != null) {
                e.initCause(lastException);
            }
            throw e;
        }
    }

    private static final int I_KEY       = 1;
    private static final int I_PARAMSPEC = 2;
    private static final int I_PARAMS    = 3;
    private static final int I_CERT      = 4;

    private void implInit(CipherSpi thisSpi, int type, int opmode, Key key,
            AlgorithmParameterSpec paramSpec, AlgorithmParameters params,
            SecureRandom random) throws InvalidKeyException,
            InvalidAlgorithmParameterException {
        switch (type) {
        case I_KEY:
            checkCryptoPerm(thisSpi, key);
            thisSpi.engineInit(opmode, key, random);
            break;
        case I_PARAMSPEC:
            checkCryptoPerm(thisSpi, key, paramSpec);
            thisSpi.engineInit(opmode, key, paramSpec, random);
            break;
        case I_PARAMS:
            checkCryptoPerm(thisSpi, key, params);
            thisSpi.engineInit(opmode, key, params, random);
            break;
        case I_CERT:
            checkCryptoPerm(thisSpi, key);
            thisSpi.engineInit(opmode, key, random);
            break;
        default:
            throw new AssertionError("Internal Cipher error: " + type);
        }
    }

    private void chooseProvider(int initType, int opmode, Key key,
            AlgorithmParameterSpec paramSpec,
            AlgorithmParameters params, SecureRandom random)
            throws InvalidKeyException, InvalidAlgorithmParameterException {
        synchronized (lock) {
            if (spi != null) {
                implInit(spi, initType, opmode, key, paramSpec, params, random);
                return;
            }
            Exception lastException = null;
            while ((firstService != null) || serviceIterator.hasNext()) {
                Service s;
                CipherSpi thisSpi;
                if (firstService != null) {
                    s = firstService;
                    thisSpi = firstSpi;
                    firstService = null;
                    firstSpi = null;
                } else {
                    s = serviceIterator.next();
                    thisSpi = null;
                }
                // if provider says it does not support this key, ignore it
                if (s.supportsParameter(key) == false) {
                    continue;
                }
                if (JceSecurity.canUseProvider(s.getProvider()) == false) {
                    continue;
                }
                Transform tr = getTransform(s, transforms);
                if (tr == null) {
                    // should never happen
                    continue;
                }
                if (tr.supportsModePadding(s) == S_NO) {
                    continue;
                }
                try {
                    if (thisSpi == null) {
                        thisSpi = (CipherSpi)s.newInstance(null);
                    }
                    tr.setModePadding(thisSpi);
                    initCryptoPermission();
                    implInit(thisSpi, initType, opmode, key, paramSpec,
                                                        params, random);
                    provider = s.getProvider();
                    this.spi = thisSpi;
                    firstService = null;
                    serviceIterator = null;
                    transforms = null;
                    return;
                } catch (Exception e) {
                    // NoSuchAlgorithmException from newInstance()
                    // InvalidKeyException from init()
                    // RuntimeException (ProviderException) from init()
                    // SecurityException from crypto permission check
                    if (lastException == null) {
                        lastException = e;
                    }
                }
            }
            // no working provider found, fail
            if (lastException instanceof InvalidKeyException) {
                throw (InvalidKeyException)lastException;
            }
            if (lastException instanceof InvalidAlgorithmParameterException) {
                throw (InvalidAlgorithmParameterException)lastException;
            }
            if (lastException instanceof RuntimeException) {
                throw (RuntimeException)lastException;
            }
            String kName = (key != null) ? key.getClass().getName() : "(null)";
            throw new InvalidKeyException
                ("No installed provider supports this key: "
                + kName, lastException);
        }
    }

    Returns the provider of this Cipher object. 
Returns: the provider of this Cipher object/**
     * Returns the provider of this {@code Cipher} object.
     *
     * @return the provider of this {@code Cipher} object
     */
    public final Provider getProvider() {
        chooseFirstProvider();
        return this.provider;
    }

    Returns the algorithm name of this Cipher object. This is the same name that was specified in one of the getInstance calls that created this Cipher object.. 
Returns: the algorithm name of this Cipher object./**
     * Returns the algorithm name of this {@code Cipher} object.
     *
     * <p>This is the same name that was specified in one of the
     * {@code getInstance} calls that created this {@code Cipher}
     * object..
     *
     * @return the algorithm name of this {@code Cipher} object.
     */
    public final String getAlgorithm() {
        return this.transformation;
    }

    Returns the block size (in bytes).
Returns: the block size (in bytes), or 0 if the underlying algorithm is
not a block cipher/**
     * Returns the block size (in bytes).
     *
     * @return the block size (in bytes), or 0 if the underlying algorithm is
     * not a block cipher
     */
    public final int getBlockSize() {
        chooseFirstProvider();
        return spi.engineGetBlockSize();
    }

    Returns the length in bytes that an output buffer would need to be in order to hold the result of the next update or doFinal operation, given the input length inputLen (in bytes). This call takes into account any unprocessed (buffered) data from a previous update call, padding, and AEAD tagging. 
The actual output length of the next update or doFinal call may be smaller than the length returned by this method. 
Params: inputLen – the input length (in bytes)
Throws: IllegalStateException – if this cipher is in a wrong state
(e.g., has not yet been initialized)
Returns: the required output buffer size (in bytes)/**
     * Returns the length in bytes that an output buffer would need to be in
     * order to hold the result of the next {@code update} or
     * {@code doFinal} operation, given the input length
     * {@code inputLen} (in bytes).
     *
     * <p>This call takes into account any unprocessed (buffered) data from a
     * previous {@code update} call, padding, and AEAD tagging.
     *
     * <p>The actual output length of the next {@code update} or
     * {@code doFinal} call may be smaller than the length returned by
     * this method.
     *
     * @param inputLen the input length (in bytes)
     *
     * @return the required output buffer size (in bytes)
     *
     * @exception IllegalStateException if this cipher is in a wrong state
     * (e.g., has not yet been initialized)
     */
    public final int getOutputSize(int inputLen) {

        if (!initialized && !(this instanceof NullCipher)) {
            throw new IllegalStateException("Cipher not initialized");
        }
        if (inputLen < 0) {
            throw new IllegalArgumentException("Input size must be equal " +
                                               "to or greater than zero");
        }
        chooseFirstProvider();
        return spi.engineGetOutputSize(inputLen);
    }

    Returns the initialization vector (IV) in a new buffer.
This is useful in the case where a random IV was created,
or in the context of password-based encryption or
decryption, where the IV is derived from a user-supplied password.
Returns: the initialization vector in a new buffer, or null if the
underlying algorithm does not use an IV, or if the IV has not yet
been set./**
     * Returns the initialization vector (IV) in a new buffer.
     *
     * <p>This is useful in the case where a random IV was created,
     * or in the context of password-based encryption or
     * decryption, where the IV is derived from a user-supplied password.
     *
     * @return the initialization vector in a new buffer, or null if the
     * underlying algorithm does not use an IV, or if the IV has not yet
     * been set.
     */
    public final byte[] getIV() {
        chooseFirstProvider();
        return spi.engineGetIV();
    }

    Returns the parameters used with this cipher.
The returned parameters may be the same that were used to initialize
this cipher, or may contain a combination of default and random
parameter values used by the underlying cipher implementation if this
cipher requires algorithm parameters but was not initialized with any.
Returns: the parameters used with this cipher, or null if this cipher
does not use any parameters./**
     * Returns the parameters used with this cipher.
     *
     * <p>The returned parameters may be the same that were used to initialize
     * this cipher, or may contain a combination of default and random
     * parameter values used by the underlying cipher implementation if this
     * cipher requires algorithm parameters but was not initialized with any.
     *
     * @return the parameters used with this cipher, or null if this cipher
     * does not use any parameters.
     */
    public final AlgorithmParameters getParameters() {
        chooseFirstProvider();
        return spi.engineGetParameters();
    }

    Returns the exemption mechanism object used with this cipher.
Returns: the exemption mechanism object used with this cipher, or
null if this cipher does not use any exemption mechanism./**
     * Returns the exemption mechanism object used with this cipher.
     *
     * @return the exemption mechanism object used with this cipher, or
     * null if this cipher does not use any exemption mechanism.
     */
    public final ExemptionMechanism getExemptionMechanism() {
        chooseFirstProvider();
        return exmech;
    }

    //
    // Crypto permission check code below
    //
    private void checkCryptoPerm(CipherSpi checkSpi, Key key)
            throws InvalidKeyException {
        if (cryptoPerm == CryptoAllPermission.INSTANCE) {
            return;
        }
        // Check if key size and default parameters are within legal limits
        AlgorithmParameterSpec params;
        try {
            params = getAlgorithmParameterSpec(checkSpi.engineGetParameters());
        } catch (InvalidParameterSpecException ipse) {
            throw new InvalidKeyException
                ("Unsupported default algorithm parameters");
        }
        if (!passCryptoPermCheck(checkSpi, key, params)) {
            throw new InvalidKeyException(
                "Illegal key size or default parameters");
        }
    }

    private void checkCryptoPerm(CipherSpi checkSpi, Key key,
            AlgorithmParameterSpec params) throws InvalidKeyException,
            InvalidAlgorithmParameterException {
        if (cryptoPerm == CryptoAllPermission.INSTANCE) {
            return;
        }
        // Determine keysize and check if it is within legal limits
        if (!passCryptoPermCheck(checkSpi, key, null)) {
            throw new InvalidKeyException("Illegal key size");
        }
        if ((params != null) && (!passCryptoPermCheck(checkSpi, key, params))) {
            throw new InvalidAlgorithmParameterException("Illegal parameters");
        }
    }

    private void checkCryptoPerm(CipherSpi checkSpi, Key key,
            AlgorithmParameters params)
            throws InvalidKeyException, InvalidAlgorithmParameterException {
        if (cryptoPerm == CryptoAllPermission.INSTANCE) {
            return;
        }
        // Convert the specified parameters into specs and then delegate.
        AlgorithmParameterSpec pSpec;
        try {
            pSpec = getAlgorithmParameterSpec(params);
        } catch (InvalidParameterSpecException ipse) {
            throw new InvalidAlgorithmParameterException
                ("Failed to retrieve algorithm parameter specification");
        }
        checkCryptoPerm(checkSpi, key, pSpec);
    }

    private boolean passCryptoPermCheck(CipherSpi checkSpi, Key key,
                                        AlgorithmParameterSpec params)
            throws InvalidKeyException {
        String em = cryptoPerm.getExemptionMechanism();
        int keySize = checkSpi.engineGetKeySize(key);
        // Use the "algorithm" component of the cipher
        // transformation so that the perm check would
        // work when the key has the "aliased" algo.
        String algComponent;
        int index = transformation.indexOf('/');
        if (index != -1) {
            algComponent = transformation.substring(0, index);
        } else {
            algComponent = transformation;
        }
        CryptoPermission checkPerm =
            new CryptoPermission(algComponent, keySize, params, em);

        if (!cryptoPerm.implies(checkPerm)) {
            if (debug != null) {
                debug.println("Crypto Permission check failed");
                debug.println("granted: " + cryptoPerm);
                debug.println("requesting: " + checkPerm);
            }
            return false;
        }
        if (exmech == null) {
            return true;
        }
        try {
            if (!exmech.isCryptoAllowed(key)) {
                if (debug != null) {
                    debug.println(exmech.getName() + " isn't enforced");
                }
                return false;
            }
        } catch (ExemptionMechanismException eme) {
            if (debug != null) {
                debug.println("Cannot determine whether "+
                              exmech.getName() + " has been enforced");
                eme.printStackTrace();
            }
            return false;
        }
        return true;
    }

    // check if opmode is one of the defined constants
    // throw InvalidParameterExeption if not
    private static void checkOpmode(int opmode) {
        if ((opmode < ENCRYPT_MODE) || (opmode > UNWRAP_MODE)) {
            throw new InvalidParameterException("Invalid operation mode");
        }
    }

    private static String getOpmodeString(int opmode) {
        switch (opmode) {
            case ENCRYPT_MODE:
                return "encryption";
            case DECRYPT_MODE:
                return "decryption";
            case WRAP_MODE:
                return "key wrapping";
            case UNWRAP_MODE:
                return "key unwrapping";
            default:
                return "";
        }
    }

    Initializes this cipher with a key.
The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode. 
If this cipher requires any algorithm parameters that cannot be derived from the given key, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise an InvalidKeyException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV). 
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them using the SecureRandom implementation of the highest-priority installed provider as the source of randomness. (If none of the installed providers supply an implementation of SecureRandom, a system-provided source of randomness will be used.) 
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
Params: opmode – the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)
key – the key
Throws: InvalidKeyException – if the given key is inappropriate for
initializing this cipher, or requires
algorithm parameters that cannot be
determined from the given key, or if the given key has a keysize that
exceeds the maximum allowable keysize (as determined from the
configured jurisdiction policy files).
UnsupportedOperationException – if opmode is WRAP_MODE or UNWRAP_MODE but the mode is not implemented by the underlying CipherSpi./**
     * Initializes this cipher with a key.
     *
     * <p>The cipher is initialized for one of the following four operations:
     * encryption, decryption, key wrapping or key unwrapping, depending
     * on the value of {@code opmode}.
     *
     * <p>If this cipher requires any algorithm parameters that cannot be
     * derived from the given {@code key}, the underlying cipher
     * implementation is supposed to generate the required parameters itself
     * (using provider-specific default or random values) if it is being
     * initialized for encryption or key wrapping, and raise an
     * {@code InvalidKeyException} if it is being
     * initialized for decryption or key unwrapping.
     * The generated parameters can be retrieved using
     * {@link #getParameters() getParameters} or
     * {@link #getIV() getIV} (if the parameter is an IV).
     *
     * <p>If this cipher requires algorithm parameters that cannot be
     * derived from the input parameters, and there are no reasonable
     * provider-specific default values, initialization will
     * necessarily fail.
     *
     * <p>If this cipher (including its underlying feedback or padding scheme)
     * requires any random bytes (e.g., for parameter generation), it will get
     * them using the {@link java.security.SecureRandom}
     * implementation of the highest-priority
     * installed provider as the source of randomness.
     * (If none of the installed providers supply an implementation of
     * SecureRandom, a system-provided source of randomness will be used.)
     *
     * <p>Note that when a Cipher object is initialized, it loses all
     * previously-acquired state. In other words, initializing a Cipher is
     * equivalent to creating a new instance of that Cipher and initializing
     * it.
     *
     * @param opmode the operation mode of this cipher (this is one of
     * the following:
     * {@code ENCRYPT_MODE}, {@code DECRYPT_MODE},
     * {@code WRAP_MODE} or {@code UNWRAP_MODE})
     * @param key the key
     *
     * @exception InvalidKeyException if the given key is inappropriate for
     * initializing this cipher, or requires
     * algorithm parameters that cannot be
     * determined from the given key, or if the given key has a keysize that
     * exceeds the maximum allowable keysize (as determined from the
     * configured jurisdiction policy files).
     * @throws UnsupportedOperationException if {@code opmode} is
     * {@code WRAP_MODE} or {@code UNWRAP_MODE} but the mode is not implemented
     * by the underlying {@code CipherSpi}.
     */
    public final void init(int opmode, Key key) throws InvalidKeyException {
        init(opmode, key, JceSecurity.RANDOM);
    }

    Initializes this cipher with a key and a source of randomness.
The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode. 
If this cipher requires any algorithm parameters that cannot be derived from the given key, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise an InvalidKeyException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV). 
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random. 
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
Params: opmode – the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)
key – the encryption key
random – the source of randomness
Throws: InvalidKeyException – if the given key is inappropriate for
initializing this cipher, or requires
algorithm parameters that cannot be
determined from the given key, or if the given key has a keysize that
exceeds the maximum allowable keysize (as determined from the
configured jurisdiction policy files).
UnsupportedOperationException – if opmode is WRAP_MODE or UNWRAP_MODE but the mode is not implemented by the underlying CipherSpi./**
     * Initializes this cipher with a key and a source of randomness.
     *
     * <p>The cipher is initialized for one of the following four operations:
     * encryption, decryption, key wrapping or  key unwrapping, depending
     * on the value of {@code opmode}.
     *
     * <p>If this cipher requires any algorithm parameters that cannot be
     * derived from the given {@code key}, the underlying cipher
     * implementation is supposed to generate the required parameters itself
     * (using provider-specific default or random values) if it is being
     * initialized for encryption or key wrapping, and raise an
     * {@code InvalidKeyException} if it is being
     * initialized for decryption or key unwrapping.
     * The generated parameters can be retrieved using
     * {@link #getParameters() getParameters} or
     * {@link #getIV() getIV} (if the parameter is an IV).
     *
     * <p>If this cipher requires algorithm parameters that cannot be
     * derived from the input parameters, and there are no reasonable
     * provider-specific default values, initialization will
     * necessarily fail.
     *
     * <p>If this cipher (including its underlying feedback or padding scheme)
     * requires any random bytes (e.g., for parameter generation), it will get
     * them from {@code random}.
     *
     * <p>Note that when a Cipher object is initialized, it loses all
     * previously-acquired state. In other words, initializing a Cipher is
     * equivalent to creating a new instance of that Cipher and initializing
     * it.
     *
     * @param opmode the operation mode of this cipher (this is one of the
     * following:
     * {@code ENCRYPT_MODE}, {@code DECRYPT_MODE},
     * {@code WRAP_MODE} or {@code UNWRAP_MODE})
     * @param key the encryption key
     * @param random the source of randomness
     *
     * @exception InvalidKeyException if the given key is inappropriate for
     * initializing this cipher, or requires
     * algorithm parameters that cannot be
     * determined from the given key, or if the given key has a keysize that
     * exceeds the maximum allowable keysize (as determined from the
     * configured jurisdiction policy files).
     * @throws UnsupportedOperationException if {@code opmode} is
     * {@code WRAP_MODE} or {@code UNWRAP_MODE} but the mode is not implemented
     * by the underlying {@code CipherSpi}.
     */
    public final void init(int opmode, Key key, SecureRandom random)
            throws InvalidKeyException
    {
        initialized = false;
        checkOpmode(opmode);

        if (spi != null) {
            checkCryptoPerm(spi, key);
            spi.engineInit(opmode, key, random);
        } else {
            try {
                chooseProvider(I_KEY, opmode, key, null, null, random);
            } catch (InvalidAlgorithmParameterException e) {
                // should never occur
                throw new InvalidKeyException(e);
            }
        }

        initialized = true;
        this.opmode = opmode;

        if (!skipDebug && pdebug != null) {
            pdebug.println("Cipher." + transformation + " " +
                getOpmodeString(opmode) + " algorithm from: " +
                getProviderName());
        }
    }

    Initializes this cipher with a key and a set of algorithm
parameters.
The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode. 
If this cipher requires any algorithm parameters and params is null, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise an InvalidAlgorithmParameterException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV). 
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them using the SecureRandom implementation of the highest-priority installed provider as the source of randomness. (If none of the installed providers supply an implementation of SecureRandom, a system-provided source of randomness will be used.) 
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
Params: opmode – the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)
key – the encryption key
params – the algorithm parameters
Throws: InvalidKeyException – if the given key is inappropriate for
initializing this cipher, or its keysize exceeds the maximum allowable
keysize (as determined from the configured jurisdiction policy files).
InvalidAlgorithmParameterException – if the given algorithm parameters are inappropriate for this cipher, or this cipher requires algorithm parameters and params is null, or the given algorithm parameters imply a cryptographic strength that would exceed the legal limits (as determined from the configured jurisdiction policy files).
UnsupportedOperationException – if opmode is WRAP_MODE or UNWRAP_MODE but the mode is not implemented by the underlying CipherSpi./**
     * Initializes this cipher with a key and a set of algorithm
     * parameters.
     *
     * <p>The cipher is initialized for one of the following four operations:
     * encryption, decryption, key wrapping or  key unwrapping, depending
     * on the value of {@code opmode}.
     *
     * <p>If this cipher requires any algorithm parameters and
     * {@code params} is null, the underlying cipher implementation is
     * supposed to generate the required parameters itself (using
     * provider-specific default or random values) if it is being
     * initialized for encryption or key wrapping, and raise an
     * {@code InvalidAlgorithmParameterException} if it is being
     * initialized for decryption or key unwrapping.
     * The generated parameters can be retrieved using
     * {@link #getParameters() getParameters} or
     * {@link #getIV() getIV} (if the parameter is an IV).
     *
     * <p>If this cipher requires algorithm parameters that cannot be
     * derived from the input parameters, and there are no reasonable
     * provider-specific default values, initialization will
     * necessarily fail.
     *
     * <p>If this cipher (including its underlying feedback or padding scheme)
     * requires any random bytes (e.g., for parameter generation), it will get
     * them using the {@link java.security.SecureRandom}
     * implementation of the highest-priority
     * installed provider as the source of randomness.
     * (If none of the installed providers supply an implementation of
     * SecureRandom, a system-provided source of randomness will be used.)
     *
     * <p>Note that when a Cipher object is initialized, it loses all
     * previously-acquired state. In other words, initializing a Cipher is
     * equivalent to creating a new instance of that Cipher and initializing
     * it.
     *
     * @param opmode the operation mode of this cipher (this is one of the
     * following:
     * {@code ENCRYPT_MODE}, {@code DECRYPT_MODE},
     * {@code WRAP_MODE} or {@code UNWRAP_MODE})
     * @param key the encryption key
     * @param params the algorithm parameters
     *
     * @exception InvalidKeyException if the given key is inappropriate for
     * initializing this cipher, or its keysize exceeds the maximum allowable
     * keysize (as determined from the configured jurisdiction policy files).
     * @exception InvalidAlgorithmParameterException if the given algorithm
     * parameters are inappropriate for this cipher,
     * or this cipher requires
     * algorithm parameters and {@code params} is null, or the given
     * algorithm parameters imply a cryptographic strength that would exceed
     * the legal limits (as determined from the configured jurisdiction
     * policy files).
     * @throws UnsupportedOperationException if {@code opmode} is
     * {@code WRAP_MODE} or {@code UNWRAP_MODE} but the mode is not implemented
     * by the underlying {@code CipherSpi}.
     */
    public final void init(int opmode, Key key, AlgorithmParameterSpec params)
            throws InvalidKeyException, InvalidAlgorithmParameterException
    {
        init(opmode, key, params, JceSecurity.RANDOM);
    }

    Initializes this cipher with a key, a set of algorithm
parameters, and a source of randomness.
The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode. 
If this cipher requires any algorithm parameters and params is null, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise an InvalidAlgorithmParameterException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV). 
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random. 
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
Params: opmode – the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)
key – the encryption key
params – the algorithm parameters
random – the source of randomness
Throws: InvalidKeyException – if the given key is inappropriate for
initializing this cipher, or its keysize exceeds the maximum allowable
keysize (as determined from the configured jurisdiction policy files).
InvalidAlgorithmParameterException – if the given algorithm parameters are inappropriate for this cipher, or this cipher requires algorithm parameters and params is null, or the given algorithm parameters imply a cryptographic strength that would exceed the legal limits (as determined from the configured jurisdiction policy files).
UnsupportedOperationException – if opmode is WRAP_MODE or UNWRAP_MODE but the mode is not implemented by the underlying CipherSpi./**
     * Initializes this cipher with a key, a set of algorithm
     * parameters, and a source of randomness.
     *
     * <p>The cipher is initialized for one of the following four operations:
     * encryption, decryption, key wrapping or  key unwrapping, depending
     * on the value of {@code opmode}.
     *
     * <p>If this cipher requires any algorithm parameters and
     * {@code params} is null, the underlying cipher implementation is
     * supposed to generate the required parameters itself (using
     * provider-specific default or random values) if it is being
     * initialized for encryption or key wrapping, and raise an
     * {@code InvalidAlgorithmParameterException} if it is being
     * initialized for decryption or key unwrapping.
     * The generated parameters can be retrieved using
     * {@link #getParameters() getParameters} or
     * {@link #getIV() getIV} (if the parameter is an IV).
     *
     * <p>If this cipher requires algorithm parameters that cannot be
     * derived from the input parameters, and there are no reasonable
     * provider-specific default values, initialization will
     * necessarily fail.
     *
     * <p>If this cipher (including its underlying feedback or padding scheme)
     * requires any random bytes (e.g., for parameter generation), it will get
     * them from {@code random}.
     *
     * <p>Note that when a Cipher object is initialized, it loses all
     * previously-acquired state. In other words, initializing a Cipher is
     * equivalent to creating a new instance of that Cipher and initializing
     * it.
     *
     * @param opmode the operation mode of this cipher (this is one of the
     * following:
     * {@code ENCRYPT_MODE}, {@code DECRYPT_MODE},
     * {@code WRAP_MODE} or {@code UNWRAP_MODE})
     * @param key the encryption key
     * @param params the algorithm parameters
     * @param random the source of randomness
     *
     * @exception InvalidKeyException if the given key is inappropriate for
     * initializing this cipher, or its keysize exceeds the maximum allowable
     * keysize (as determined from the configured jurisdiction policy files).
     * @exception InvalidAlgorithmParameterException if the given algorithm
     * parameters are inappropriate for this cipher,
     * or this cipher requires
     * algorithm parameters and {@code params} is null, or the given
     * algorithm parameters imply a cryptographic strength that would exceed
     * the legal limits (as determined from the configured jurisdiction
     * policy files).
     * @throws UnsupportedOperationException if {@code opmode} is
     * {@code WRAP_MODE} or {@code UNWRAP_MODE} but the mode is not implemented
     * by the underlying {@code CipherSpi}.
     */
    public final void init(int opmode, Key key, AlgorithmParameterSpec params,
                           SecureRandom random)
            throws InvalidKeyException, InvalidAlgorithmParameterException
    {
        initialized = false;
        checkOpmode(opmode);

        if (spi != null) {
            checkCryptoPerm(spi, key, params);
            spi.engineInit(opmode, key, params, random);
        } else {
            chooseProvider(I_PARAMSPEC, opmode, key, params, null, random);
        }

        initialized = true;
        this.opmode = opmode;

        if (!skipDebug && pdebug != null) {
            pdebug.println("Cipher." + transformation + " " +
                getOpmodeString(opmode) + " algorithm from: " +
                getProviderName());
        }
    }

    Initializes this cipher with a key and a set of algorithm
parameters.
The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode. 
If this cipher requires any algorithm parameters and params is null, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise an InvalidAlgorithmParameterException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV). 
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them using the SecureRandom implementation of the highest-priority installed provider as the source of randomness. (If none of the installed providers supply an implementation of SecureRandom, a system-provided source of randomness will be used.) 
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
Params: opmode – the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)
key – the encryption key
params – the algorithm parameters
Throws: InvalidKeyException – if the given key is inappropriate for
initializing this cipher, or its keysize exceeds the maximum allowable
keysize (as determined from the configured jurisdiction policy files).
InvalidAlgorithmParameterException – if the given algorithm parameters are inappropriate for this cipher, or this cipher requires algorithm parameters and params is null, or the given algorithm parameters imply a cryptographic strength that would exceed the legal limits (as determined from the configured jurisdiction policy files).
UnsupportedOperationException – if opmode is WRAP_MODE or UNWRAP_MODE but the mode is not implemented by the underlying CipherSpi./**
     * Initializes this cipher with a key and a set of algorithm
     * parameters.
     *
     * <p>The cipher is initialized for one of the following four operations:
     * encryption, decryption, key wrapping or  key unwrapping, depending
     * on the value of {@code opmode}.
     *
     * <p>If this cipher requires any algorithm parameters and
     * {@code params} is null, the underlying cipher implementation is
     * supposed to generate the required parameters itself (using
     * provider-specific default or random values) if it is being
     * initialized for encryption or key wrapping, and raise an
     * {@code InvalidAlgorithmParameterException} if it is being
     * initialized for decryption or key unwrapping.
     * The generated parameters can be retrieved using
     * {@link #getParameters() getParameters} or
     * {@link #getIV() getIV} (if the parameter is an IV).
     *
     * <p>If this cipher requires algorithm parameters that cannot be
     * derived from the input parameters, and there are no reasonable
     * provider-specific default values, initialization will
     * necessarily fail.
     *
     * <p>If this cipher (including its underlying feedback or padding scheme)
     * requires any random bytes (e.g., for parameter generation), it will get
     * them using the {@link java.security.SecureRandom}
     * implementation of the highest-priority
     * installed provider as the source of randomness.
     * (If none of the installed providers supply an implementation of
     * SecureRandom, a system-provided source of randomness will be used.)
     *
     * <p>Note that when a Cipher object is initialized, it loses all
     * previously-acquired state. In other words, initializing a Cipher is
     * equivalent to creating a new instance of that Cipher and initializing
     * it.
     *
     * @param opmode the operation mode of this cipher (this is one of the
     * following: {@code ENCRYPT_MODE},
     * {@code DECRYPT_MODE}, {@code WRAP_MODE}
     * or {@code UNWRAP_MODE})
     * @param key the encryption key
     * @param params the algorithm parameters
     *
     * @exception InvalidKeyException if the given key is inappropriate for
     * initializing this cipher, or its keysize exceeds the maximum allowable
     * keysize (as determined from the configured jurisdiction policy files).
     * @exception InvalidAlgorithmParameterException if the given algorithm
     * parameters are inappropriate for this cipher,
     * or this cipher requires
     * algorithm parameters and {@code params} is null, or the given
     * algorithm parameters imply a cryptographic strength that would exceed
     * the legal limits (as determined from the configured jurisdiction
     * policy files).
     * @throws UnsupportedOperationException if {@code opmode} is
     * {@code WRAP_MODE} or {@code UNWRAP_MODE} but the mode is not implemented
     * by the underlying {@code CipherSpi}.
     */
    public final void init(int opmode, Key key, AlgorithmParameters params)
            throws InvalidKeyException, InvalidAlgorithmParameterException
    {
        init(opmode, key, params, JceSecurity.RANDOM);
    }

    Initializes this cipher with a key, a set of algorithm
parameters, and a source of randomness.
The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode. 
If this cipher requires any algorithm parameters and params is null, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise an InvalidAlgorithmParameterException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV). 
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random. 
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
Params: opmode – the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)
key – the encryption key
params – the algorithm parameters
random – the source of randomness
Throws: InvalidKeyException – if the given key is inappropriate for
initializing this cipher, or its keysize exceeds the maximum allowable
keysize (as determined from the configured jurisdiction policy files).
InvalidAlgorithmParameterException – if the given algorithm parameters are inappropriate for this cipher, or this cipher requires algorithm parameters and params is null, or the given algorithm parameters imply a cryptographic strength that would exceed the legal limits (as determined from the configured jurisdiction policy files).
UnsupportedOperationException – if opmode is WRAP_MODE or UNWRAP_MODE but the mode is not implemented by the underlying CipherSpi./**
     * Initializes this cipher with a key, a set of algorithm
     * parameters, and a source of randomness.
     *
     * <p>The cipher is initialized for one of the following four operations:
     * encryption, decryption, key wrapping or  key unwrapping, depending
     * on the value of {@code opmode}.
     *
     * <p>If this cipher requires any algorithm parameters and
     * {@code params} is null, the underlying cipher implementation is
     * supposed to generate the required parameters itself (using
     * provider-specific default or random values) if it is being
     * initialized for encryption or key wrapping, and raise an
     * {@code InvalidAlgorithmParameterException} if it is being
     * initialized for decryption or key unwrapping.
     * The generated parameters can be retrieved using
     * {@link #getParameters() getParameters} or
     * {@link #getIV() getIV} (if the parameter is an IV).
     *
     * <p>If this cipher requires algorithm parameters that cannot be
     * derived from the input parameters, and there are no reasonable
     * provider-specific default values, initialization will
     * necessarily fail.
     *
     * <p>If this cipher (including its underlying feedback or padding scheme)
     * requires any random bytes (e.g., for parameter generation), it will get
     * them from {@code random}.
     *
     * <p>Note that when a Cipher object is initialized, it loses all
     * previously-acquired state. In other words, initializing a Cipher is
     * equivalent to creating a new instance of that Cipher and initializing
     * it.
     *
     * @param opmode the operation mode of this cipher (this is one of the
     * following: {@code ENCRYPT_MODE},
     * {@code DECRYPT_MODE}, {@code WRAP_MODE}
     * or {@code UNWRAP_MODE})
     * @param key the encryption key
     * @param params the algorithm parameters
     * @param random the source of randomness
     *
     * @exception InvalidKeyException if the given key is inappropriate for
     * initializing this cipher, or its keysize exceeds the maximum allowable
     * keysize (as determined from the configured jurisdiction policy files).
     * @exception InvalidAlgorithmParameterException if the given algorithm
     * parameters are inappropriate for this cipher,
     * or this cipher requires
     * algorithm parameters and {@code params} is null, or the given
     * algorithm parameters imply a cryptographic strength that would exceed
     * the legal limits (as determined from the configured jurisdiction
     * policy files).
     * @throws UnsupportedOperationException if {@code opmode} is
     * {@code WRAP_MODE} or {@code UNWRAP_MODE} but the mode is not implemented
     * by the underlying {@code CipherSpi}.
     */
    public final void init(int opmode, Key key, AlgorithmParameters params,
                           SecureRandom random)
            throws InvalidKeyException, InvalidAlgorithmParameterException
    {
        initialized = false;
        checkOpmode(opmode);

        if (spi != null) {
            checkCryptoPerm(spi, key, params);
            spi.engineInit(opmode, key, params, random);
        } else {
            chooseProvider(I_PARAMS, opmode, key, null, params, random);
        }

        initialized = true;
        this.opmode = opmode;

        if (!skipDebug && pdebug != null) {
            pdebug.println("Cipher." + transformation + " " +
                getOpmodeString(opmode) + " algorithm from: " +
                getProviderName());
        }
    }

    Initializes this cipher with the public key from the given certificate.
 The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode. 
If the certificate is of type X.509 and has a key usage
extension field marked as critical, and the value of the key usage extension field implies that the public key in the certificate and its corresponding private key are not supposed to be used for the operation represented by the value of opmode, an InvalidKeyException is thrown. 
 If this cipher requires any algorithm parameters that cannot be derived from the public key in the given certificate, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise an InvalidKeyException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV). 
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them using the SecureRandom implementation of the highest-priority installed provider as the source of randomness. (If none of the installed providers supply an implementation of SecureRandom, a system-provided source of randomness will be used.) 
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
Params: opmode – the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)
certificate – the certificate
Throws: InvalidKeyException – if the public key in the given
certificate is inappropriate for initializing this cipher, or this
cipher requires algorithm parameters that cannot be determined from the
public key in the given certificate, or the keysize of the public key
in the given certificate has a keysize that exceeds the maximum
allowable keysize (as determined by the configured jurisdiction policy
files).
UnsupportedOperationException – if opmode is WRAP_MODE or UNWRAP_MODE but the mode is not implemented by the underlying CipherSpi./**
     * Initializes this cipher with the public key from the given certificate.
     * <p> The cipher is initialized for one of the following four operations:
     * encryption, decryption, key wrapping or  key unwrapping, depending
     * on the value of {@code opmode}.
     *
     * <p>If the certificate is of type X.509 and has a <i>key usage</i>
     * extension field marked as critical, and the value of the <i>key usage</i>
     * extension field implies that the public key in
     * the certificate and its corresponding private key are not
     * supposed to be used for the operation represented by the value
     * of {@code opmode},
     * an {@code InvalidKeyException}
     * is thrown.
     *
     * <p> If this cipher requires any algorithm parameters that cannot be
     * derived from the public key in the given certificate, the underlying
     * cipher
     * implementation is supposed to generate the required parameters itself
     * (using provider-specific default or random values) if it is being
     * initialized for encryption or key wrapping, and raise an
     * {@code InvalidKeyException} if it is being initialized for decryption or
     * key unwrapping.
     * The generated parameters can be retrieved using
     * {@link #getParameters() getParameters} or
     * {@link #getIV() getIV} (if the parameter is an IV).
     *
     * <p>If this cipher requires algorithm parameters that cannot be
     * derived from the input parameters, and there are no reasonable
     * provider-specific default values, initialization will
     * necessarily fail.
     *
     * <p>If this cipher (including its underlying feedback or padding scheme)
     * requires any random bytes (e.g., for parameter generation), it will get
     * them using the
     * {@code SecureRandom}
     * implementation of the highest-priority
     * installed provider as the source of randomness.
     * (If none of the installed providers supply an implementation of
     * SecureRandom, a system-provided source of randomness will be used.)
     *
     * <p>Note that when a Cipher object is initialized, it loses all
     * previously-acquired state. In other words, initializing a Cipher is
     * equivalent to creating a new instance of that Cipher and initializing
     * it.
     *
     * @param opmode the operation mode of this cipher (this is one of the
     * following:
     * {@code ENCRYPT_MODE}, {@code DECRYPT_MODE},
     * {@code WRAP_MODE} or {@code UNWRAP_MODE})
     * @param certificate the certificate
     *
     * @exception InvalidKeyException if the public key in the given
     * certificate is inappropriate for initializing this cipher, or this
     * cipher requires algorithm parameters that cannot be determined from the
     * public key in the given certificate, or the keysize of the public key
     * in the given certificate has a keysize that exceeds the maximum
     * allowable keysize (as determined by the configured jurisdiction policy
     * files).
     * @throws UnsupportedOperationException if {@code opmode} is
     * {@code WRAP_MODE} or {@code UNWRAP_MODE} but the mode is not implemented
     * by the underlying {@code CipherSpi}.
     */
    public final void init(int opmode, Certificate certificate)
            throws InvalidKeyException
    {
        init(opmode, certificate, JceSecurity.RANDOM);
    }

    Initializes this cipher with the public key from the given certificate
and
a source of randomness.
The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode. 
If the certificate is of type X.509 and has a key usage
extension field marked as critical, and the value of the key usage extension field implies that the public key in the certificate and its corresponding private key are not supposed to be used for the operation represented by the value of opmode, an InvalidKeyException is thrown. 
If this cipher requires any algorithm parameters that cannot be derived from the public key in the given certificate, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise an InvalidKeyException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV). 
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random. 
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
Params: opmode – the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)
certificate – the certificate
random – the source of randomness
Throws: InvalidKeyException – if the public key in the given
certificate is inappropriate for initializing this cipher, or this
cipher
requires algorithm parameters that cannot be determined from the
public key in the given certificate, or the keysize of the public key
in the given certificate has a keysize that exceeds the maximum
allowable keysize (as determined by the configured jurisdiction policy
files).
UnsupportedOperationException – if opmode is WRAP_MODE or UNWRAP_MODE but the mode is not implemented by the underlying CipherSpi./**
     * Initializes this cipher with the public key from the given certificate
     * and
     * a source of randomness.
     *
     * <p>The cipher is initialized for one of the following four operations:
     * encryption, decryption, key wrapping
     * or key unwrapping, depending on
     * the value of {@code opmode}.
     *
     * <p>If the certificate is of type X.509 and has a <i>key usage</i>
     * extension field marked as critical, and the value of the <i>key usage</i>
     * extension field implies that the public key in
     * the certificate and its corresponding private key are not
     * supposed to be used for the operation represented by the value of
     * {@code opmode},
     * an {@code InvalidKeyException}
     * is thrown.
     *
     * <p>If this cipher requires any algorithm parameters that cannot be
     * derived from the public key in the given {@code certificate},
     * the underlying cipher
     * implementation is supposed to generate the required parameters itself
     * (using provider-specific default or random values) if it is being
     * initialized for encryption or key wrapping, and raise an
     * {@code InvalidKeyException} if it is being
     * initialized for decryption or key unwrapping.
     * The generated parameters can be retrieved using
     * {@link #getParameters() getParameters} or
     * {@link #getIV() getIV} (if the parameter is an IV).
     *
     * <p>If this cipher requires algorithm parameters that cannot be
     * derived from the input parameters, and there are no reasonable
     * provider-specific default values, initialization will
     * necessarily fail.
     *
     * <p>If this cipher (including its underlying feedback or padding scheme)
     * requires any random bytes (e.g., for parameter generation), it will get
     * them from {@code random}.
     *
     * <p>Note that when a Cipher object is initialized, it loses all
     * previously-acquired state. In other words, initializing a Cipher is
     * equivalent to creating a new instance of that Cipher and initializing
     * it.
     *
     * @param opmode the operation mode of this cipher (this is one of the
     * following:
     * {@code ENCRYPT_MODE}, {@code DECRYPT_MODE},
     * {@code WRAP_MODE} or {@code UNWRAP_MODE})
     * @param certificate the certificate
     * @param random the source of randomness
     *
     * @exception InvalidKeyException if the public key in the given
     * certificate is inappropriate for initializing this cipher, or this
     * cipher
     * requires algorithm parameters that cannot be determined from the
     * public key in the given certificate, or the keysize of the public key
     * in the given certificate has a keysize that exceeds the maximum
     * allowable keysize (as determined by the configured jurisdiction policy
     * files).
     * @throws UnsupportedOperationException if {@code opmode} is
     * {@code WRAP_MODE} or {@code UNWRAP_MODE} but the mode is not implemented
     * by the underlying {@code CipherSpi}.
     */
    public final void init(int opmode, Certificate certificate,
                           SecureRandom random)
            throws InvalidKeyException
    {
        initialized = false;
        checkOpmode(opmode);

        // Check key usage if the certificate is of
        // type X.509.
        if (certificate instanceof java.security.cert.X509Certificate) {
            // Check whether the cert has a key usage extension
            // marked as a critical extension.
            X509Certificate cert = (X509Certificate)certificate;
            Set<String> critSet = cert.getCriticalExtensionOIDs();

            if (critSet != null && !critSet.isEmpty()
                && critSet.contains(KEY_USAGE_EXTENSION_OID)) {
                boolean[] keyUsageInfo = cert.getKeyUsage();
                // keyUsageInfo[2] is for keyEncipherment;
                // keyUsageInfo[3] is for dataEncipherment.
                if ((keyUsageInfo != null) &&
                    (((opmode == Cipher.ENCRYPT_MODE) &&
                      (keyUsageInfo.length > 3) &&
                      (keyUsageInfo[3] == false)) ||
                     ((opmode == Cipher.WRAP_MODE) &&
                      (keyUsageInfo.length > 2) &&
                      (keyUsageInfo[2] == false)))) {
                    throw new InvalidKeyException("Wrong key usage");
                }
            }
        }

        PublicKey publicKey =
            (certificate==null? null:certificate.getPublicKey());

        if (spi != null) {
            checkCryptoPerm(spi, publicKey);
            spi.engineInit(opmode, publicKey, random);
        } else {
            try {
                chooseProvider(I_CERT, opmode, publicKey, null, null, random);
            } catch (InvalidAlgorithmParameterException e) {
                // should never occur
                throw new InvalidKeyException(e);
            }
        }

        initialized = true;
        this.opmode = opmode;

        if (!skipDebug && pdebug != null) {
            pdebug.println("Cipher." + transformation + " " +
                getOpmodeString(opmode) + " algorithm from: " +
                getProviderName());
        }
    }

    Ensures that Cipher is in a valid state for update() and doFinal()
calls - should be initialized and in ENCRYPT_MODE or DECRYPT_MODE.
Throws: IllegalStateException – if Cipher object is not in valid state./**
     * Ensures that Cipher is in a valid state for update() and doFinal()
     * calls - should be initialized and in ENCRYPT_MODE or DECRYPT_MODE.
     * @throws IllegalStateException if Cipher object is not in valid state.
     */
    private void checkCipherState() {
        if (!(this instanceof NullCipher)) {
            if (!initialized) {
                throw new IllegalStateException("Cipher not initialized");
            }
            if ((opmode != Cipher.ENCRYPT_MODE) &&
                (opmode != Cipher.DECRYPT_MODE)) {
                throw new IllegalStateException("Cipher not initialized " +
                                                "for encryption/decryption");
            }
        }
    }

    Continues a multiple-part encryption or decryption operation
(depending on how this cipher was initialized), processing another data
part.
The bytes in the input buffer are processed, and the result is stored in a new buffer. 
If input has a length of zero, this method returns null. 
Params: input – the input buffer
Throws: IllegalStateException – if this cipher is in a wrong state
(e.g., has not been initialized)
Returns: the new buffer with the result, or null if the underlying
cipher is a block cipher and the input data is too short to result in a
new block./**
     * Continues a multiple-part encryption or decryption operation
     * (depending on how this cipher was initialized), processing another data
     * part.
     *
     * <p>The bytes in the {@code input} buffer are processed, and the
     * result is stored in a new buffer.
     *
     * <p>If {@code input} has a length of zero, this method returns
     * {@code null}.
     *
     * @param input the input buffer
     *
     * @return the new buffer with the result, or null if the underlying
     * cipher is a block cipher and the input data is too short to result in a
     * new block.
     *
     * @exception IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized)
     */
    public final byte[] update(byte[] input) {
        checkCipherState();

        // Input sanity check
        if (input == null) {
            throw new IllegalArgumentException("Null input buffer");
        }

        chooseFirstProvider();
        if (input.length == 0) {
            return null;
        }
        return spi.engineUpdate(input, 0, input.length);
    }

    Continues a multiple-part encryption or decryption operation
(depending on how this cipher was initialized), processing another data
part.
The first inputLen bytes in the input buffer, starting at inputOffset inclusive, are processed, and the result is stored in a new buffer. 
If inputLen is zero, this method returns null. 
Params: input – the input buffer
inputOffset – the offset in input where the input starts
inputLen – the input length
Throws: IllegalStateException – if this cipher is in a wrong state
(e.g., has not been initialized)
Returns: the new buffer with the result, or null if the underlying
cipher is a block cipher and the input data is too short to result in a
new block./**
     * Continues a multiple-part encryption or decryption operation
     * (depending on how this cipher was initialized), processing another data
     * part.
     *
     * <p>The first {@code inputLen} bytes in the {@code input}
     * buffer, starting at {@code inputOffset} inclusive, are processed,
     * and the result is stored in a new buffer.
     *
     * <p>If {@code inputLen} is zero, this method returns
     * {@code null}.
     *
     * @param input the input buffer
     * @param inputOffset the offset in {@code input} where the input
     * starts
     * @param inputLen the input length
     *
     * @return the new buffer with the result, or null if the underlying
     * cipher is a block cipher and the input data is too short to result in a
     * new block.
     *
     * @exception IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized)
     */
    public final byte[] update(byte[] input, int inputOffset, int inputLen) {
        checkCipherState();

        // Input sanity check
        if (input == null || inputOffset < 0
            || inputLen > (input.length - inputOffset) || inputLen < 0) {
            throw new IllegalArgumentException("Bad arguments");
        }

        chooseFirstProvider();
        if (inputLen == 0) {
            return null;
        }
        return spi.engineUpdate(input, inputOffset, inputLen);
    }

    Continues a multiple-part encryption or decryption operation
(depending on how this cipher was initialized), processing another data
part.
The first inputLen bytes in the input buffer, starting at inputOffset inclusive, are processed, and the result is stored in the output buffer. 
If the output buffer is too small to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use getOutputSize to determine how big the output buffer should be. 
If inputLen is zero, this method returns a length of zero. 
Note: this method should be copy-safe, which means the input and output buffers can reference the same byte array and no unprocessed input data is overwritten when the result is copied into the output buffer. 
Params: input – the input buffer
inputOffset – the offset in input where the input starts
inputLen – the input length
output – the buffer for the result
Throws: IllegalStateException – if this cipher is in a wrong state
(e.g., has not been initialized)
ShortBufferException – if the given output buffer is too small
to hold the result
Returns: the number of bytes stored in output/**
     * Continues a multiple-part encryption or decryption operation
     * (depending on how this cipher was initialized), processing another data
     * part.
     *
     * <p>The first {@code inputLen} bytes in the {@code input}
     * buffer, starting at {@code inputOffset} inclusive, are processed,
     * and the result is stored in the {@code output} buffer.
     *
     * <p>If the {@code output} buffer is too small to hold the result,
     * a {@code ShortBufferException} is thrown. In this case, repeat this
     * call with a larger output buffer. Use
     * {@link #getOutputSize(int) getOutputSize} to determine how big
     * the output buffer should be.
     *
     * <p>If {@code inputLen} is zero, this method returns
     * a length of zero.
     *
     * <p>Note: this method should be copy-safe, which means the
     * {@code input} and {@code output} buffers can reference
     * the same byte array and no unprocessed input data is overwritten
     * when the result is copied into the output buffer.
     *
     * @param input the input buffer
     * @param inputOffset the offset in {@code input} where the input
     * starts
     * @param inputLen the input length
     * @param output the buffer for the result
     *
     * @return the number of bytes stored in {@code output}
     *
     * @exception IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized)
     * @exception ShortBufferException if the given output buffer is too small
     * to hold the result
     */
    public final int update(byte[] input, int inputOffset, int inputLen,
                            byte[] output)
            throws ShortBufferException {
        checkCipherState();

        // Input sanity check
        if (input == null || inputOffset < 0
            || inputLen > (input.length - inputOffset) || inputLen < 0) {
            throw new IllegalArgumentException("Bad arguments");
        }

        chooseFirstProvider();
        if (inputLen == 0) {
            return 0;
        }
        return spi.engineUpdate(input, inputOffset, inputLen,
                                      output, 0);
    }

    Continues a multiple-part encryption or decryption operation
(depending on how this cipher was initialized), processing another data
part.
The first inputLen bytes in the input buffer, starting at inputOffset inclusive, are processed, and the result is stored in the output buffer, starting at outputOffset inclusive. 
If the output buffer is too small to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use getOutputSize to determine how big the output buffer should be. 
If inputLen is zero, this method returns a length of zero. 
Note: this method should be copy-safe, which means the input and output buffers can reference the same byte array and no unprocessed input data is overwritten when the result is copied into the output buffer. 
Params: input – the input buffer
inputOffset – the offset in input where the input starts
inputLen – the input length
output – the buffer for the result
outputOffset – the offset in output where the result is stored
Throws: IllegalStateException – if this cipher is in a wrong state
(e.g., has not been initialized)
ShortBufferException – if the given output buffer is too small
to hold the result
Returns: the number of bytes stored in output/**
     * Continues a multiple-part encryption or decryption operation
     * (depending on how this cipher was initialized), processing another data
     * part.
     *
     * <p>The first {@code inputLen} bytes in the {@code input}
     * buffer, starting at {@code inputOffset} inclusive, are processed,
     * and the result is stored in the {@code output} buffer, starting at
     * {@code outputOffset} inclusive.
     *
     * <p>If the {@code output} buffer is too small to hold the result,
     * a {@code ShortBufferException} is thrown. In this case, repeat this
     * call with a larger output buffer. Use
     * {@link #getOutputSize(int) getOutputSize} to determine how big
     * the output buffer should be.
     *
     * <p>If {@code inputLen} is zero, this method returns
     * a length of zero.
     *
     * <p>Note: this method should be copy-safe, which means the
     * {@code input} and {@code output} buffers can reference
     * the same byte array and no unprocessed input data is overwritten
     * when the result is copied into the output buffer.
     *
     * @param input the input buffer
     * @param inputOffset the offset in {@code input} where the input
     * starts
     * @param inputLen the input length
     * @param output the buffer for the result
     * @param outputOffset the offset in {@code output} where the result
     * is stored
     *
     * @return the number of bytes stored in {@code output}
     *
     * @exception IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized)
     * @exception ShortBufferException if the given output buffer is too small
     * to hold the result
     */
    public final int update(byte[] input, int inputOffset, int inputLen,
                            byte[] output, int outputOffset)
            throws ShortBufferException {
        checkCipherState();

        // Input sanity check
        if (input == null || inputOffset < 0
            || inputLen > (input.length - inputOffset) || inputLen < 0
            || outputOffset < 0) {
            throw new IllegalArgumentException("Bad arguments");
        }

        chooseFirstProvider();
        if (inputLen == 0) {
            return 0;
        }
        return spi.engineUpdate(input, inputOffset, inputLen,
                                      output, outputOffset);
    }

    Continues a multiple-part encryption or decryption operation
(depending on how this cipher was initialized), processing another data
part.
All input.remaining() bytes starting at input.position() are processed. The result is stored in the output buffer. Upon return, the input buffer's position will be equal to its limit; its limit will not have changed. The output buffer's position will have advanced by n, where n is the value returned by this method; the output buffer's limit will not have changed. 
If output.remaining() bytes are insufficient to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use getOutputSize to determine how big the output buffer should be. 
Note: this method should be copy-safe, which means the input and output buffers can reference the same block of memory and no unprocessed input data is overwritten when the result is copied into the output buffer. 
Params: input – the input ByteBuffer
output – the output ByteByffer
Throws: IllegalStateException – if this cipher is in a wrong state
(e.g., has not been initialized)
IllegalArgumentException – if input and output are the
  same object
ReadOnlyBufferException – if the output buffer is read-only
ShortBufferException – if there is insufficient space in the
output buffer
Returns: the number of bytes stored in output
Since: 1.5/**
     * Continues a multiple-part encryption or decryption operation
     * (depending on how this cipher was initialized), processing another data
     * part.
     *
     * <p>All {@code input.remaining()} bytes starting at
     * {@code input.position()} are processed. The result is stored
     * in the output buffer.
     * Upon return, the input buffer's position will be equal
     * to its limit; its limit will not have changed. The output buffer's
     * position will have advanced by n, where n is the value returned
     * by this method; the output buffer's limit will not have changed.
     *
     * <p>If {@code output.remaining()} bytes are insufficient to
     * hold the result, a {@code ShortBufferException} is thrown.
     * In this case, repeat this call with a larger output buffer. Use
     * {@link #getOutputSize(int) getOutputSize} to determine how big
     * the output buffer should be.
     *
     * <p>Note: this method should be copy-safe, which means the
     * {@code input} and {@code output} buffers can reference
     * the same block of memory and no unprocessed input data is overwritten
     * when the result is copied into the output buffer.
     *
     * @param input the input ByteBuffer
     * @param output the output ByteByffer
     *
     * @return the number of bytes stored in {@code output}
     *
     * @exception IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized)
     * @exception IllegalArgumentException if input and output are the
     *   same object
     * @exception ReadOnlyBufferException if the output buffer is read-only
     * @exception ShortBufferException if there is insufficient space in the
     * output buffer
     * @since 1.5
     */
    public final int update(ByteBuffer input, ByteBuffer output)
            throws ShortBufferException {
        checkCipherState();

        if ((input == null) || (output == null)) {
            throw new IllegalArgumentException("Buffers must not be null");
        }
        if (input == output) {
            throw new IllegalArgumentException("Input and output buffers must "
                + "not be the same object, consider using buffer.duplicate()");
        }
        if (output.isReadOnly()) {
            throw new ReadOnlyBufferException();
        }

        chooseFirstProvider();
        return spi.engineUpdate(input, output);
    }

    Finishes a multiple-part encryption or decryption operation, depending
on how this cipher was initialized.
Input data that may have been buffered during a previous update operation is processed, with padding (if requested) being applied. If an AEAD mode such as GCM/CCM is being used, the authentication tag is appended in the case of encryption, or verified in the case of decryption. The result is stored in a new buffer. 
Upon finishing, this method resets this cipher object to the state it was in when previously initialized via a call to init. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call to init) more data. 
Note: if any exception is thrown, this cipher object may need to
be reset before it can be used again.
Throws: IllegalStateException – if this cipher is in a wrong state
(e.g., has not been initialized)
IllegalBlockSizeException – if this cipher is a block cipher,
no padding has been requested (only in encryption mode), and the total
input length of the data processed by this cipher is not a multiple of
block size; or if this encryption algorithm is unable to
process the input data provided.
BadPaddingException – if this cipher is in decryption mode,
and (un)padding has been requested, but the decrypted data is not
bounded by the appropriate padding bytes
AEADBadTagException – if this cipher is decrypting in an
AEAD mode (such as GCM/CCM), and the received authentication tag
does not match the calculated value
Returns: the new buffer with the result/**
     * Finishes a multiple-part encryption or decryption operation, depending
     * on how this cipher was initialized.
     *
     * <p>Input data that may have been buffered during a previous
     * {@code update} operation is processed, with padding (if requested)
     * being applied.
     * If an AEAD mode such as GCM/CCM is being used, the authentication
     * tag is appended in the case of encryption, or verified in the
     * case of decryption.
     * The result is stored in a new buffer.
     *
     * <p>Upon finishing, this method resets this cipher object to the state
     * it was in when previously initialized via a call to {@code init}.
     * That is, the object is reset and available to encrypt or decrypt
     * (depending on the operation mode that was specified in the call to
     * {@code init}) more data.
     *
     * <p>Note: if any exception is thrown, this cipher object may need to
     * be reset before it can be used again.
     *
     * @return the new buffer with the result
     *
     * @exception IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized)
     * @exception IllegalBlockSizeException if this cipher is a block cipher,
     * no padding has been requested (only in encryption mode), and the total
     * input length of the data processed by this cipher is not a multiple of
     * block size; or if this encryption algorithm is unable to
     * process the input data provided.
     * @exception BadPaddingException if this cipher is in decryption mode,
     * and (un)padding has been requested, but the decrypted data is not
     * bounded by the appropriate padding bytes
     * @exception AEADBadTagException if this cipher is decrypting in an
     * AEAD mode (such as GCM/CCM), and the received authentication tag
     * does not match the calculated value
     */
    public final byte[] doFinal()
            throws IllegalBlockSizeException, BadPaddingException {
        checkCipherState();

        chooseFirstProvider();
        return spi.engineDoFinal(null, 0, 0);
    }

    Finishes a multiple-part encryption or decryption operation, depending
on how this cipher was initialized.
Input data that may have been buffered during a previous update operation is processed, with padding (if requested) being applied. If an AEAD mode such as GCM/CCM is being used, the authentication tag is appended in the case of encryption, or verified in the case of decryption. The result is stored in the output buffer, starting at outputOffset inclusive. 
If the output buffer is too small to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use getOutputSize to determine how big the output buffer should be. 
Upon finishing, this method resets this cipher object to the state it was in when previously initialized via a call to init. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call to init) more data. 
Note: if any exception is thrown, this cipher object may need to
be reset before it can be used again.
Params: output – the buffer for the result
outputOffset – the offset in output where the result is stored
Throws: IllegalStateException – if this cipher is in a wrong state
(e.g., has not been initialized)
IllegalBlockSizeException – if this cipher is a block cipher,
no padding has been requested (only in encryption mode), and the total
input length of the data processed by this cipher is not a multiple of
block size; or if this encryption algorithm is unable to
process the input data provided.
ShortBufferException – if the given output buffer is too small
to hold the result
BadPaddingException – if this cipher is in decryption mode,
and (un)padding has been requested, but the decrypted data is not
bounded by the appropriate padding bytes
AEADBadTagException – if this cipher is decrypting in an
AEAD mode (such as GCM/CCM), and the received authentication tag
does not match the calculated value
Returns: the number of bytes stored in output/**
     * Finishes a multiple-part encryption or decryption operation, depending
     * on how this cipher was initialized.
     *
     * <p>Input data that may have been buffered during a previous
     * {@code update} operation is processed, with padding (if requested)
     * being applied.
     * If an AEAD mode such as GCM/CCM is being used, the authentication
     * tag is appended in the case of encryption, or verified in the
     * case of decryption.
     * The result is stored in the {@code output} buffer, starting at
     * {@code outputOffset} inclusive.
     *
     * <p>If the {@code output} buffer is too small to hold the result,
     * a {@code ShortBufferException} is thrown. In this case, repeat this
     * call with a larger output buffer. Use
     * {@link #getOutputSize(int) getOutputSize} to determine how big
     * the output buffer should be.
     *
     * <p>Upon finishing, this method resets this cipher object to the state
     * it was in when previously initialized via a call to {@code init}.
     * That is, the object is reset and available to encrypt or decrypt
     * (depending on the operation mode that was specified in the call to
     * {@code init}) more data.
     *
     * <p>Note: if any exception is thrown, this cipher object may need to
     * be reset before it can be used again.
     *
     * @param output the buffer for the result
     * @param outputOffset the offset in {@code output} where the result
     * is stored
     *
     * @return the number of bytes stored in {@code output}
     *
     * @exception IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized)
     * @exception IllegalBlockSizeException if this cipher is a block cipher,
     * no padding has been requested (only in encryption mode), and the total
     * input length of the data processed by this cipher is not a multiple of
     * block size; or if this encryption algorithm is unable to
     * process the input data provided.
     * @exception ShortBufferException if the given output buffer is too small
     * to hold the result
     * @exception BadPaddingException if this cipher is in decryption mode,
     * and (un)padding has been requested, but the decrypted data is not
     * bounded by the appropriate padding bytes
     * @exception AEADBadTagException if this cipher is decrypting in an
     * AEAD mode (such as GCM/CCM), and the received authentication tag
     * does not match the calculated value
     */
    public final int doFinal(byte[] output, int outputOffset)
            throws IllegalBlockSizeException, ShortBufferException,
               BadPaddingException {
        checkCipherState();

        // Input sanity check
        if ((output == null) || (outputOffset < 0)) {
            throw new IllegalArgumentException("Bad arguments");
        }

        chooseFirstProvider();
        return spi.engineDoFinal(null, 0, 0, output, outputOffset);
    }

    Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation. The data is encrypted or decrypted,
depending on how this cipher was initialized.
The bytes in the input buffer, and any input bytes that may have been buffered during a previous update operation, are processed, with padding (if requested) being applied. If an AEAD mode such as GCM/CCM is being used, the authentication tag is appended in the case of encryption, or verified in the case of decryption. The result is stored in a new buffer. 
Upon finishing, this method resets this cipher object to the state it was in when previously initialized via a call to init. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call to init) more data. 
Note: if any exception is thrown, this cipher object may need to
be reset before it can be used again.
Params: input – the input buffer
Throws: IllegalStateException – if this cipher is in a wrong state
(e.g., has not been initialized)
IllegalBlockSizeException – if this cipher is a block cipher,
no padding has been requested (only in encryption mode), and the total
input length of the data processed by this cipher is not a multiple of
block size; or if this encryption algorithm is unable to
process the input data provided.
BadPaddingException – if this cipher is in decryption mode,
and (un)padding has been requested, but the decrypted data is not
bounded by the appropriate padding bytes
AEADBadTagException – if this cipher is decrypting in an
AEAD mode (such as GCM/CCM), and the received authentication tag
does not match the calculated value
Returns: the new buffer with the result/**
     * Encrypts or decrypts data in a single-part operation, or finishes a
     * multiple-part operation. The data is encrypted or decrypted,
     * depending on how this cipher was initialized.
     *
     * <p>The bytes in the {@code input} buffer, and any input bytes that
     * may have been buffered during a previous {@code update} operation,
     * are processed, with padding (if requested) being applied.
     * If an AEAD mode such as GCM/CCM is being used, the authentication
     * tag is appended in the case of encryption, or verified in the
     * case of decryption.
     * The result is stored in a new buffer.
     *
     * <p>Upon finishing, this method resets this cipher object to the state
     * it was in when previously initialized via a call to {@code init}.
     * That is, the object is reset and available to encrypt or decrypt
     * (depending on the operation mode that was specified in the call to
     * {@code init}) more data.
     *
     * <p>Note: if any exception is thrown, this cipher object may need to
     * be reset before it can be used again.
     *
     * @param input the input buffer
     *
     * @return the new buffer with the result
     *
     * @exception IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized)
     * @exception IllegalBlockSizeException if this cipher is a block cipher,
     * no padding has been requested (only in encryption mode), and the total
     * input length of the data processed by this cipher is not a multiple of
     * block size; or if this encryption algorithm is unable to
     * process the input data provided.
     * @exception BadPaddingException if this cipher is in decryption mode,
     * and (un)padding has been requested, but the decrypted data is not
     * bounded by the appropriate padding bytes
     * @exception AEADBadTagException if this cipher is decrypting in an
     * AEAD mode (such as GCM/CCM), and the received authentication tag
     * does not match the calculated value
     */
    public final byte[] doFinal(byte[] input)
            throws IllegalBlockSizeException, BadPaddingException {
        checkCipherState();

        // Input sanity check
        if (input == null) {
            throw new IllegalArgumentException("Null input buffer");
        }

        chooseFirstProvider();
        return spi.engineDoFinal(input, 0, input.length);
    }

    Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation. The data is encrypted or decrypted,
depending on how this cipher was initialized.
The first inputLen bytes in the input buffer, starting at inputOffset inclusive, and any input bytes that may have been buffered during a previous update operation, are processed, with padding (if requested) being applied. If an AEAD mode such as GCM/CCM is being used, the authentication tag is appended in the case of encryption, or verified in the case of decryption. The result is stored in a new buffer. 
Upon finishing, this method resets this cipher object to the state it was in when previously initialized via a call to init. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call to init) more data. 
Note: if any exception is thrown, this cipher object may need to
be reset before it can be used again.
Params: input – the input buffer
inputOffset – the offset in input where the input starts
inputLen – the input length
Throws: IllegalStateException – if this cipher is in a wrong state
(e.g., has not been initialized)
IllegalBlockSizeException – if this cipher is a block cipher,
no padding has been requested (only in encryption mode), and the total
input length of the data processed by this cipher is not a multiple of
block size; or if this encryption algorithm is unable to
process the input data provided.
BadPaddingException – if this cipher is in decryption mode,
and (un)padding has been requested, but the decrypted data is not
bounded by the appropriate padding bytes
AEADBadTagException – if this cipher is decrypting in an
AEAD mode (such as GCM/CCM), and the received authentication tag
does not match the calculated value
Returns: the new buffer with the result/**
     * Encrypts or decrypts data in a single-part operation, or finishes a
     * multiple-part operation. The data is encrypted or decrypted,
     * depending on how this cipher was initialized.
     *
     * <p>The first {@code inputLen} bytes in the {@code input}
     * buffer, starting at {@code inputOffset} inclusive, and any input
     * bytes that may have been buffered during a previous {@code update}
     * operation, are processed, with padding (if requested) being applied.
     * If an AEAD mode such as GCM/CCM is being used, the authentication
     * tag is appended in the case of encryption, or verified in the
     * case of decryption.
     * The result is stored in a new buffer.
     *
     * <p>Upon finishing, this method resets this cipher object to the state
     * it was in when previously initialized via a call to {@code init}.
     * That is, the object is reset and available to encrypt or decrypt
     * (depending on the operation mode that was specified in the call to
     * {@code init}) more data.
     *
     * <p>Note: if any exception is thrown, this cipher object may need to
     * be reset before it can be used again.
     *
     * @param input the input buffer
     * @param inputOffset the offset in {@code input} where the input
     * starts
     * @param inputLen the input length
     *
     * @return the new buffer with the result
     *
     * @exception IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized)
     * @exception IllegalBlockSizeException if this cipher is a block cipher,
     * no padding has been requested (only in encryption mode), and the total
     * input length of the data processed by this cipher is not a multiple of
     * block size; or if this encryption algorithm is unable to
     * process the input data provided.
     * @exception BadPaddingException if this cipher is in decryption mode,
     * and (un)padding has been requested, but the decrypted data is not
     * bounded by the appropriate padding bytes
     * @exception AEADBadTagException if this cipher is decrypting in an
     * AEAD mode (such as GCM/CCM), and the received authentication tag
     * does not match the calculated value
     */
    public final byte[] doFinal(byte[] input, int inputOffset, int inputLen)
            throws IllegalBlockSizeException, BadPaddingException {
        checkCipherState();

        // Input sanity check
        if (input == null || inputOffset < 0
            || inputLen > (input.length - inputOffset) || inputLen < 0) {
            throw new IllegalArgumentException("Bad arguments");
        }

        chooseFirstProvider();
        return spi.engineDoFinal(input, inputOffset, inputLen);
    }

    Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation. The data is encrypted or decrypted,
depending on how this cipher was initialized.
The first inputLen bytes in the input buffer, starting at inputOffset inclusive, and any input bytes that may have been buffered during a previous update operation, are processed, with padding (if requested) being applied. If an AEAD mode such as GCM/CCM is being used, the authentication tag is appended in the case of encryption, or verified in the case of decryption. The result is stored in the output buffer. 
If the output buffer is too small to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use getOutputSize to determine how big the output buffer should be. 
Upon finishing, this method resets this cipher object to the state it was in when previously initialized via a call to init. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call to init) more data. 
Note: if any exception is thrown, this cipher object may need to
be reset before it can be used again.
Note: this method should be copy-safe, which means the input and output buffers can reference the same byte array and no unprocessed input data is overwritten when the result is copied into the output buffer. 
Params: input – the input buffer
inputOffset – the offset in input where the input starts
inputLen – the input length
output – the buffer for the result
Throws: IllegalStateException – if this cipher is in a wrong state
(e.g., has not been initialized)
IllegalBlockSizeException – if this cipher is a block cipher,
no padding has been requested (only in encryption mode), and the total
input length of the data processed by this cipher is not a multiple of
block size; or if this encryption algorithm is unable to
process the input data provided.
ShortBufferException – if the given output buffer is too small
to hold the result
BadPaddingException – if this cipher is in decryption mode,
and (un)padding has been requested, but the decrypted data is not
bounded by the appropriate padding bytes
AEADBadTagException – if this cipher is decrypting in an
AEAD mode (such as GCM/CCM), and the received authentication tag
does not match the calculated value
Returns: the number of bytes stored in output/**
     * Encrypts or decrypts data in a single-part operation, or finishes a
     * multiple-part operation. The data is encrypted or decrypted,
     * depending on how this cipher was initialized.
     *
     * <p>The first {@code inputLen} bytes in the {@code input}
     * buffer, starting at {@code inputOffset} inclusive, and any input
     * bytes that may have been buffered during a previous {@code update}
     * operation, are processed, with padding (if requested) being applied.
     * If an AEAD mode such as GCM/CCM is being used, the authentication
     * tag is appended in the case of encryption, or verified in the
     * case of decryption.
     * The result is stored in the {@code output} buffer.
     *
     * <p>If the {@code output} buffer is too small to hold the result,
     * a {@code ShortBufferException} is thrown. In this case, repeat this
     * call with a larger output buffer. Use
     * {@link #getOutputSize(int) getOutputSize} to determine how big
     * the output buffer should be.
     *
     * <p>Upon finishing, this method resets this cipher object to the state
     * it was in when previously initialized via a call to {@code init}.
     * That is, the object is reset and available to encrypt or decrypt
     * (depending on the operation mode that was specified in the call to
     * {@code init}) more data.
     *
     * <p>Note: if any exception is thrown, this cipher object may need to
     * be reset before it can be used again.
     *
     * <p>Note: this method should be copy-safe, which means the
     * {@code input} and {@code output} buffers can reference
     * the same byte array and no unprocessed input data is overwritten
     * when the result is copied into the output buffer.
     *
     * @param input the input buffer
     * @param inputOffset the offset in {@code input} where the input
     * starts
     * @param inputLen the input length
     * @param output the buffer for the result
     *
     * @return the number of bytes stored in {@code output}
     *
     * @exception IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized)
     * @exception IllegalBlockSizeException if this cipher is a block cipher,
     * no padding has been requested (only in encryption mode), and the total
     * input length of the data processed by this cipher is not a multiple of
     * block size; or if this encryption algorithm is unable to
     * process the input data provided.
     * @exception ShortBufferException if the given output buffer is too small
     * to hold the result
     * @exception BadPaddingException if this cipher is in decryption mode,
     * and (un)padding has been requested, but the decrypted data is not
     * bounded by the appropriate padding bytes
     * @exception AEADBadTagException if this cipher is decrypting in an
     * AEAD mode (such as GCM/CCM), and the received authentication tag
     * does not match the calculated value
     */
    public final int doFinal(byte[] input, int inputOffset, int inputLen,
                             byte[] output)
            throws ShortBufferException, IllegalBlockSizeException,
            BadPaddingException {
        checkCipherState();

        // Input sanity check
        if (input == null || inputOffset < 0
            || inputLen > (input.length - inputOffset) || inputLen < 0) {
            throw new IllegalArgumentException("Bad arguments");
        }

        chooseFirstProvider();
        return spi.engineDoFinal(input, inputOffset, inputLen,
                                       output, 0);
    }

    Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation. The data is encrypted or decrypted,
depending on how this cipher was initialized.
The first inputLen bytes in the input buffer, starting at inputOffset inclusive, and any input bytes that may have been buffered during a previous update operation, are processed, with padding (if requested) being applied. If an AEAD mode such as GCM/CCM is being used, the authentication tag is appended in the case of encryption, or verified in the case of decryption. The result is stored in the output buffer, starting at outputOffset inclusive. 
If the output buffer is too small to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use getOutputSize to determine how big the output buffer should be. 
Upon finishing, this method resets this cipher object to the state it was in when previously initialized via a call to init. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call to init) more data. 
Note: if any exception is thrown, this cipher object may need to
be reset before it can be used again.
Note: this method should be copy-safe, which means the input and output buffers can reference the same byte array and no unprocessed input data is overwritten when the result is copied into the output buffer. 
Params: input – the input buffer
inputOffset – the offset in input where the input starts
inputLen – the input length
output – the buffer for the result
outputOffset – the offset in output where the result is stored
Throws: IllegalStateException – if this cipher is in a wrong state
(e.g., has not been initialized)
IllegalBlockSizeException – if this cipher is a block cipher,
no padding has been requested (only in encryption mode), and the total
input length of the data processed by this cipher is not a multiple of
block size; or if this encryption algorithm is unable to
process the input data provided.
ShortBufferException – if the given output buffer is too small
to hold the result
BadPaddingException – if this cipher is in decryption mode,
and (un)padding has been requested, but the decrypted data is not
bounded by the appropriate padding bytes
AEADBadTagException – if this cipher is decrypting in an
AEAD mode (such as GCM/CCM), and the received authentication tag
does not match the calculated value
Returns: the number of bytes stored in output/**
     * Encrypts or decrypts data in a single-part operation, or finishes a
     * multiple-part operation. The data is encrypted or decrypted,
     * depending on how this cipher was initialized.
     *
     * <p>The first {@code inputLen} bytes in the {@code input}
     * buffer, starting at {@code inputOffset} inclusive, and any input
     * bytes that may have been buffered during a previous
     * {@code update} operation, are processed, with padding
     * (if requested) being applied.
     * If an AEAD mode such as GCM/CCM is being used, the authentication
     * tag is appended in the case of encryption, or verified in the
     * case of decryption.
     * The result is stored in the {@code output} buffer, starting at
     * {@code outputOffset} inclusive.
     *
     * <p>If the {@code output} buffer is too small to hold the result,
     * a {@code ShortBufferException} is thrown. In this case, repeat this
     * call with a larger output buffer. Use
     * {@link #getOutputSize(int) getOutputSize} to determine how big
     * the output buffer should be.
     *
     * <p>Upon finishing, this method resets this cipher object to the state
     * it was in when previously initialized via a call to {@code init}.
     * That is, the object is reset and available to encrypt or decrypt
     * (depending on the operation mode that was specified in the call to
     * {@code init}) more data.
     *
     * <p>Note: if any exception is thrown, this cipher object may need to
     * be reset before it can be used again.
     *
     * <p>Note: this method should be copy-safe, which means the
     * {@code input} and {@code output} buffers can reference
     * the same byte array and no unprocessed input data is overwritten
     * when the result is copied into the output buffer.
     *
     * @param input the input buffer
     * @param inputOffset the offset in {@code input} where the input
     * starts
     * @param inputLen the input length
     * @param output the buffer for the result
     * @param outputOffset the offset in {@code output} where the result
     * is stored
     *
     * @return the number of bytes stored in {@code output}
     *
     * @exception IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized)
     * @exception IllegalBlockSizeException if this cipher is a block cipher,
     * no padding has been requested (only in encryption mode), and the total
     * input length of the data processed by this cipher is not a multiple of
     * block size; or if this encryption algorithm is unable to
     * process the input data provided.
     * @exception ShortBufferException if the given output buffer is too small
     * to hold the result
     * @exception BadPaddingException if this cipher is in decryption mode,
     * and (un)padding has been requested, but the decrypted data is not
     * bounded by the appropriate padding bytes
     * @exception AEADBadTagException if this cipher is decrypting in an
     * AEAD mode (such as GCM/CCM), and the received authentication tag
     * does not match the calculated value
     */
    public final int doFinal(byte[] input, int inputOffset, int inputLen,
                             byte[] output, int outputOffset)
            throws ShortBufferException, IllegalBlockSizeException,
            BadPaddingException {
        checkCipherState();

        // Input sanity check
        if (input == null || inputOffset < 0
            || inputLen > (input.length - inputOffset) || inputLen < 0
            || outputOffset < 0) {
            throw new IllegalArgumentException("Bad arguments");
        }

        chooseFirstProvider();
        return spi.engineDoFinal(input, inputOffset, inputLen,
                                       output, outputOffset);
    }

    Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation. The data is encrypted or decrypted,
depending on how this cipher was initialized.
All input.remaining() bytes starting at input.position() are processed. If an AEAD mode such as GCM/CCM is being used, the authentication tag is appended in the case of encryption, or verified in the case of decryption. The result is stored in the output buffer. Upon return, the input buffer's position will be equal to its limit; its limit will not have changed. The output buffer's position will have advanced by n, where n is the value returned by this method; the output buffer's limit will not have changed. 
If output.remaining() bytes are insufficient to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use getOutputSize to determine how big the output buffer should be. 
Upon finishing, this method resets this cipher object to the state it was in when previously initialized via a call to init. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call to init) more data. 
Note: if any exception is thrown, this cipher object may need to
be reset before it can be used again.
Note: this method should be copy-safe, which means the input and output buffers can reference the same byte array and no unprocessed input data is overwritten when the result is copied into the output buffer. 
Params: input – the input ByteBuffer
output – the output ByteBuffer
Throws: IllegalStateException – if this cipher is in a wrong state
(e.g., has not been initialized)
IllegalArgumentException – if input and output are the
  same object
ReadOnlyBufferException – if the output buffer is read-only
IllegalBlockSizeException – if this cipher is a block cipher,
no padding has been requested (only in encryption mode), and the total
input length of the data processed by this cipher is not a multiple of
block size; or if this encryption algorithm is unable to
process the input data provided.
ShortBufferException – if there is insufficient space in the
output buffer
BadPaddingException – if this cipher is in decryption mode,
and (un)padding has been requested, but the decrypted data is not
bounded by the appropriate padding bytes
AEADBadTagException – if this cipher is decrypting in an
AEAD mode (such as GCM/CCM), and the received authentication tag
does not match the calculated value
Returns: the number of bytes stored in output
Since: 1.5/**
     * Encrypts or decrypts data in a single-part operation, or finishes a
     * multiple-part operation. The data is encrypted or decrypted,
     * depending on how this cipher was initialized.
     *
     * <p>All {@code input.remaining()} bytes starting at
     * {@code input.position()} are processed.
     * If an AEAD mode such as GCM/CCM is being used, the authentication
     * tag is appended in the case of encryption, or verified in the
     * case of decryption.
     * The result is stored in the output buffer.
     * Upon return, the input buffer's position will be equal
     * to its limit; its limit will not have changed. The output buffer's
     * position will have advanced by n, where n is the value returned
     * by this method; the output buffer's limit will not have changed.
     *
     * <p>If {@code output.remaining()} bytes are insufficient to
     * hold the result, a {@code ShortBufferException} is thrown.
     * In this case, repeat this call with a larger output buffer. Use
     * {@link #getOutputSize(int) getOutputSize} to determine how big
     * the output buffer should be.
     *
     * <p>Upon finishing, this method resets this cipher object to the state
     * it was in when previously initialized via a call to {@code init}.
     * That is, the object is reset and available to encrypt or decrypt
     * (depending on the operation mode that was specified in the call to
     * {@code init}) more data.
     *
     * <p>Note: if any exception is thrown, this cipher object may need to
     * be reset before it can be used again.
     *
     * <p>Note: this method should be copy-safe, which means the
     * {@code input} and {@code output} buffers can reference
     * the same byte array and no unprocessed input data is overwritten
     * when the result is copied into the output buffer.
     *
     * @param input the input ByteBuffer
     * @param output the output ByteBuffer
     *
     * @return the number of bytes stored in {@code output}
     *
     * @exception IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized)
     * @exception IllegalArgumentException if input and output are the
     *   same object
     * @exception ReadOnlyBufferException if the output buffer is read-only
     * @exception IllegalBlockSizeException if this cipher is a block cipher,
     * no padding has been requested (only in encryption mode), and the total
     * input length of the data processed by this cipher is not a multiple of
     * block size; or if this encryption algorithm is unable to
     * process the input data provided.
     * @exception ShortBufferException if there is insufficient space in the
     * output buffer
     * @exception BadPaddingException if this cipher is in decryption mode,
     * and (un)padding has been requested, but the decrypted data is not
     * bounded by the appropriate padding bytes
     * @exception AEADBadTagException if this cipher is decrypting in an
     * AEAD mode (such as GCM/CCM), and the received authentication tag
     * does not match the calculated value
     *
     * @since 1.5
     */
    public final int doFinal(ByteBuffer input, ByteBuffer output)
            throws ShortBufferException, IllegalBlockSizeException,
            BadPaddingException {
        checkCipherState();

        if ((input == null) || (output == null)) {
            throw new IllegalArgumentException("Buffers must not be null");
        }
        if (input == output) {
            throw new IllegalArgumentException("Input and output buffers must "
                + "not be the same object, consider using buffer.duplicate()");
        }
        if (output.isReadOnly()) {
            throw new ReadOnlyBufferException();
        }

        chooseFirstProvider();
        return spi.engineDoFinal(input, output);
    }

    Wrap a key.
Params: key – the key to be wrapped.
Throws: IllegalStateException – if this cipher is in a wrong
state (e.g., has not been initialized).
IllegalBlockSizeException – if this cipher is a block
cipher, no padding has been requested, and the length of the
encoding of the key to be wrapped is not a
multiple of the block size.
InvalidKeyException – if it is impossible or unsafe to
wrap the key with this cipher (e.g., a hardware protected key is
being passed to a software-only cipher).
UnsupportedOperationException – if the corresponding method in the CipherSpi is not supported.
Returns: the wrapped key./**
     * Wrap a key.
     *
     * @param key the key to be wrapped.
     *
     * @return the wrapped key.
     *
     * @exception IllegalStateException if this cipher is in a wrong
     * state (e.g., has not been initialized).
     *
     * @exception IllegalBlockSizeException if this cipher is a block
     * cipher, no padding has been requested, and the length of the
     * encoding of the key to be wrapped is not a
     * multiple of the block size.
     *
     * @exception InvalidKeyException if it is impossible or unsafe to
     * wrap the key with this cipher (e.g., a hardware protected key is
     * being passed to a software-only cipher).
     *
     * @throws UnsupportedOperationException if the corresponding method in the
     * {@code CipherSpi} is not supported.
     */
    public final byte[] wrap(Key key)
            throws IllegalBlockSizeException, InvalidKeyException {
        if (!(this instanceof NullCipher)) {
            if (!initialized) {
                throw new IllegalStateException("Cipher not initialized");
            }
            if (opmode != Cipher.WRAP_MODE) {
                throw new IllegalStateException("Cipher not initialized " +
                                                "for wrapping keys");
            }
        }

        chooseFirstProvider();
        return spi.engineWrap(key);
    }

    Unwrap a previously wrapped key.
Params: wrappedKey – the key to be unwrapped.
wrappedKeyAlgorithm – the algorithm associated with the wrapped
key.
wrappedKeyType – the type of the wrapped key. This must be one of SECRET_KEY, PRIVATE_KEY, or PUBLIC_KEY.
Throws: IllegalStateException – if this cipher is in a wrong state
(e.g., has not been initialized).
NoSuchAlgorithmException – if no installed providers can create keys of type wrappedKeyType for the wrappedKeyAlgorithm.
InvalidKeyException – if wrappedKey does not represent a wrapped key of type wrappedKeyType for the wrappedKeyAlgorithm.
UnsupportedOperationException – if the corresponding method in the CipherSpi is not supported.
Returns: the unwrapped key./**
     * Unwrap a previously wrapped key.
     *
     * @param wrappedKey the key to be unwrapped.
     *
     * @param wrappedKeyAlgorithm the algorithm associated with the wrapped
     * key.
     *
     * @param wrappedKeyType the type of the wrapped key. This must be one of
     * {@code SECRET_KEY}, {@code PRIVATE_KEY}, or
     * {@code PUBLIC_KEY}.
     *
     * @return the unwrapped key.
     *
     * @exception IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized).
     *
     * @exception NoSuchAlgorithmException if no installed providers
     * can create keys of type {@code wrappedKeyType} for the
     * {@code wrappedKeyAlgorithm}.
     *
     * @exception InvalidKeyException if {@code wrappedKey} does not
     * represent a wrapped key of type {@code wrappedKeyType} for
     * the {@code wrappedKeyAlgorithm}.
     *
     * @throws UnsupportedOperationException if the corresponding method in the
     * {@code CipherSpi} is not supported.
     */
    public final Key unwrap(byte[] wrappedKey,
                            String wrappedKeyAlgorithm,
                            int wrappedKeyType)
            throws InvalidKeyException, NoSuchAlgorithmException {

        if (!(this instanceof NullCipher)) {
            if (!initialized) {
                throw new IllegalStateException("Cipher not initialized");
            }
            if (opmode != Cipher.UNWRAP_MODE) {
                throw new IllegalStateException("Cipher not initialized " +
                                                "for unwrapping keys");
            }
        }
        if ((wrappedKeyType != SECRET_KEY) &&
            (wrappedKeyType != PRIVATE_KEY) &&
            (wrappedKeyType != PUBLIC_KEY)) {
            throw new InvalidParameterException("Invalid key type");
        }

        chooseFirstProvider();
        return spi.engineUnwrap(wrappedKey,
                                      wrappedKeyAlgorithm,
                                      wrappedKeyType);
    }

    private AlgorithmParameterSpec getAlgorithmParameterSpec(
                                      AlgorithmParameters params)
            throws InvalidParameterSpecException {
        if (params == null) {
            return null;
        }

        String alg = params.getAlgorithm().toUpperCase(Locale.ENGLISH);

        if (alg.equalsIgnoreCase("RC2")) {
            return params.getParameterSpec(RC2ParameterSpec.class);
        }

        if (alg.equalsIgnoreCase("RC5")) {
            return params.getParameterSpec(RC5ParameterSpec.class);
        }

        if (alg.startsWith("PBE")) {
            return params.getParameterSpec(PBEParameterSpec.class);
        }

        if (alg.startsWith("DES")) {
            return params.getParameterSpec(IvParameterSpec.class);
        }
        return null;
    }

    private static CryptoPermission getConfiguredPermission(
            String transformation) throws NullPointerException,
            NoSuchAlgorithmException {
        if (transformation == null) throw new NullPointerException();
        String[] parts = tokenizeTransformation(transformation);
        return JceSecurityManager.INSTANCE.getCryptoPermission(parts[0]);
    }

    Returns the maximum key length for the specified transformation
according to the installed JCE jurisdiction policy files. If
JCE unlimited strength jurisdiction policy files are installed,
Integer.MAX_VALUE will be returned.
For more information on the default key sizes and the JCE jurisdiction
policy files, please see the Cryptographic defaults and limitations in
the {@extLink security_guide_jdk_providers JDK Providers Documentation}.
Params: transformation – the cipher transformation.
Throws: NullPointerException – if transformation is null.
NoSuchAlgorithmException – if transformation is not a valid transformation, i.e. in the form of "algorithm" or "algorithm/mode/padding".
Returns: the maximum key length in bits or Integer.MAX_VALUE.
Since: 1.5/**
     * Returns the maximum key length for the specified transformation
     * according to the installed JCE jurisdiction policy files. If
     * JCE unlimited strength jurisdiction policy files are installed,
     * Integer.MAX_VALUE will be returned.
     * For more information on the default key sizes and the JCE jurisdiction
     * policy files, please see the Cryptographic defaults and limitations in
     * the {@extLink security_guide_jdk_providers JDK Providers Documentation}.
     *
     * @param transformation the cipher transformation.
     * @return the maximum key length in bits or Integer.MAX_VALUE.
     * @exception NullPointerException if {@code transformation} is null.
     * @exception NoSuchAlgorithmException if {@code transformation}
     * is not a valid transformation, i.e. in the form of "algorithm" or
     * "algorithm/mode/padding".
     * @since 1.5
     */
    public static final int getMaxAllowedKeyLength(String transformation)
            throws NoSuchAlgorithmException {
        CryptoPermission cp = getConfiguredPermission(transformation);
        return cp.getMaxKeySize();
    }

    Returns an AlgorithmParameterSpec object which contains
the maximum cipher parameter value according to the
jurisdiction policy file. If JCE unlimited strength jurisdiction
policy files are installed or there is no maximum limit on the
parameters for the specified transformation in the policy file,
null will be returned.
Params: transformation – the cipher transformation.
Throws: NullPointerException – if transformation is null.
NoSuchAlgorithmException – if transformation is not a valid transformation, i.e. in the form of "algorithm" or "algorithm/mode/padding".
Returns: an AlgorithmParameterSpec which holds the maximum
value or null.
Since: 1.5/**
     * Returns an AlgorithmParameterSpec object which contains
     * the maximum cipher parameter value according to the
     * jurisdiction policy file. If JCE unlimited strength jurisdiction
     * policy files are installed or there is no maximum limit on the
     * parameters for the specified transformation in the policy file,
     * null will be returned.
     *
     * @param transformation the cipher transformation.
     * @return an AlgorithmParameterSpec which holds the maximum
     * value or null.
     * @exception NullPointerException if {@code transformation}
     * is null.
     * @exception NoSuchAlgorithmException if {@code transformation}
     * is not a valid transformation, i.e. in the form of "algorithm" or
     * "algorithm/mode/padding".
     * @since 1.5
     */
    public static final AlgorithmParameterSpec getMaxAllowedParameterSpec(
            String transformation) throws NoSuchAlgorithmException {
        CryptoPermission cp = getConfiguredPermission(transformation);
        return cp.getAlgorithmParameterSpec();
    }

    Continues a multi-part update of the Additional Authentication
Data (AAD).
 Calls to this method provide AAD to the cipher when operating in modes such as AEAD (GCM/CCM). If this cipher is operating in either GCM or CCM mode, all AAD must be supplied before beginning operations on the ciphertext (via the update and doFinal methods). 
Params: src – the buffer containing the Additional Authentication Data
Throws: IllegalArgumentException – if the src byte array is null
IllegalStateException – if this cipher is in a wrong state (e.g., has not been initialized), does not accept AAD, or if operating in either GCM or CCM mode and one of the update methods has already been called for the active encryption/decryption operation
UnsupportedOperationException – if the corresponding method in the CipherSpi has not been overridden by an implementation
Since: 1.7/**
     * Continues a multi-part update of the Additional Authentication
     * Data (AAD).
     * <p>
     * Calls to this method provide AAD to the cipher when operating in
     * modes such as AEAD (GCM/CCM).  If this cipher is operating in
     * either GCM or CCM mode, all AAD must be supplied before beginning
     * operations on the ciphertext (via the {@code update} and
     * {@code doFinal} methods).
     *
     * @param src the buffer containing the Additional Authentication Data
     *
     * @throws IllegalArgumentException if the {@code src}
     * byte array is null
     * @throws IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized), does not accept AAD, or if
     * operating in either GCM or CCM mode and one of the {@code update}
     * methods has already been called for the active
     * encryption/decryption operation
     * @throws UnsupportedOperationException if the corresponding method
     * in the {@code CipherSpi} has not been overridden by an
     * implementation
     *
     * @since 1.7
     */
    public final void updateAAD(byte[] src) {
        if (src == null) {
            throw new IllegalArgumentException("src buffer is null");
        }

        updateAAD(src, 0, src.length);
    }

    Continues a multi-part update of the Additional Authentication
Data (AAD), using a subset of the provided buffer.
 Calls to this method provide AAD to the cipher when operating in modes such as AEAD (GCM/CCM). If this cipher is operating in either GCM or CCM mode, all AAD must be supplied before beginning operations on the ciphertext (via the update and doFinal methods). 
Params: src – the buffer containing the AAD
offset – the offset in src where the AAD input starts
len – the number of AAD bytes
Throws: IllegalArgumentException – if the src byte array is null, or the offset or length is less than 0, or the sum of the offset and len is greater than the length of the src byte array
IllegalStateException – if this cipher is in a wrong state (e.g., has not been initialized), does not accept AAD, or if operating in either GCM or CCM mode and one of the update methods has already been called for the active encryption/decryption operation
UnsupportedOperationException – if the corresponding method in the CipherSpi has not been overridden by an implementation
Since: 1.7/**
     * Continues a multi-part update of the Additional Authentication
     * Data (AAD), using a subset of the provided buffer.
     * <p>
     * Calls to this method provide AAD to the cipher when operating in
     * modes such as AEAD (GCM/CCM).  If this cipher is operating in
     * either GCM or CCM mode, all AAD must be supplied before beginning
     * operations on the ciphertext (via the {@code update}
     * and {@code doFinal} methods).
     *
     * @param src the buffer containing the AAD
     * @param offset the offset in {@code src} where the AAD input starts
     * @param len the number of AAD bytes
     *
     * @throws IllegalArgumentException if the {@code src}
     * byte array is null, or the {@code offset} or {@code length}
     * is less than 0, or the sum of the {@code offset} and
     * {@code len} is greater than the length of the
     * {@code src} byte array
     * @throws IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized), does not accept AAD, or if
     * operating in either GCM or CCM mode and one of the {@code update}
     * methods has already been called for the active
     * encryption/decryption operation
     * @throws UnsupportedOperationException if the corresponding method
     * in the {@code CipherSpi} has not been overridden by an
     * implementation
     *
     * @since 1.7
     */
    public final void updateAAD(byte[] src, int offset, int len) {
        checkCipherState();

        // Input sanity check
        if ((src == null) || (offset < 0) || (len < 0)
                || len > (src.length - offset)) {
            throw new IllegalArgumentException("Bad arguments");
        }

        chooseFirstProvider();
        if (len == 0) {
            return;
        }
        spi.engineUpdateAAD(src, offset, len);
    }

    Continues a multi-part update of the Additional Authentication
Data (AAD).
 Calls to this method provide AAD to the cipher when operating in modes such as AEAD (GCM/CCM). If this cipher is operating in either GCM or CCM mode, all AAD must be supplied before beginning operations on the ciphertext (via the update and doFinal methods). 
 All src.remaining() bytes starting at src.position() are processed. Upon return, the input buffer's position will be equal to its limit; its limit will not have changed. 
Params: src – the buffer containing the AAD
Throws: IllegalArgumentException – if the src ByteBuffer is null
IllegalStateException – if this cipher is in a wrong state (e.g., has not been initialized), does not accept AAD, or if operating in either GCM or CCM mode and one of the update methods has already been called for the active encryption/decryption operation
UnsupportedOperationException – if the corresponding method in the CipherSpi has not been overridden by an implementation
Since: 1.7/**
     * Continues a multi-part update of the Additional Authentication
     * Data (AAD).
     * <p>
     * Calls to this method provide AAD to the cipher when operating in
     * modes such as AEAD (GCM/CCM).  If this cipher is operating in
     * either GCM or CCM mode, all AAD must be supplied before beginning
     * operations on the ciphertext (via the {@code update}
     * and {@code doFinal} methods).
     * <p>
     * All {@code src.remaining()} bytes starting at
     * {@code src.position()} are processed.
     * Upon return, the input buffer's position will be equal
     * to its limit; its limit will not have changed.
     *
     * @param src the buffer containing the AAD
     *
     * @throws IllegalArgumentException if the {@code src ByteBuffer}
     * is null
     * @throws IllegalStateException if this cipher is in a wrong state
     * (e.g., has not been initialized), does not accept AAD, or if
     * operating in either GCM or CCM mode and one of the {@code update}
     * methods has already been called for the active
     * encryption/decryption operation
     * @throws UnsupportedOperationException if the corresponding method
     * in the {@code CipherSpi} has not been overridden by an
     * implementation
     *
     * @since 1.7
     */
    public final void updateAAD(ByteBuffer src) {
        checkCipherState();

        // Input sanity check
        if (src == null) {
            throw new IllegalArgumentException("src ByteBuffer is null");
        }

        chooseFirstProvider();
        if (src.remaining() == 0) {
            return;
        }
        spi.engineUpdateAAD(src);
    }
}
Params:	transformation – the name of the transformation, e.g., AES/CBC/PKCS5Padding. See the Cipher section in the Java Security Standard Algorithm Names Specification for information about standard transformation names.
Throws:	NoSuchAlgorithmException – if `transformation` is `null`, empty, in an invalid format, or if no `Provider` supports a `CipherSpi` implementation for the specified algorithm NoSuchPaddingException – if `transformation` contains a padding scheme that is not available
See Also:	Provider
Implementation Note:	The JDK Reference Implementation additionally uses the `jdk.security.provider.preferred` `Security` property to determine the preferred provider order for the specified algorithm. This may be different than the order of providers returned by `Security.getProviders()`.
Returns:	a cipher that implements the requested transformation
Params:	inputLen – the input length (in bytes)
Throws:	IllegalStateException – if this cipher is in a wrong state (e.g., has not yet been initialized)
Returns:	the required output buffer size (in bytes)
Params:	input – the input buffer
Throws:	IllegalStateException – if this cipher is in a wrong state (e.g., has not been initialized)
Returns:	the new buffer with the result, or null if the underlying cipher is a block cipher and the input data is too short to result in a new block.
Params:	input – the input buffer inputOffset – the offset in `input` where the input starts inputLen – the input length
Throws:	IllegalStateException – if this cipher is in a wrong state (e.g., has not been initialized)
Returns:	the new buffer with the result, or null if the underlying cipher is a block cipher and the input data is too short to result in a new block.
Params:	input – the input ByteBuffer output – the output ByteByffer
Throws:	IllegalStateException – if this cipher is in a wrong state (e.g., has not been initialized) IllegalArgumentException – if input and output are the same object ReadOnlyBufferException – if the output buffer is read-only ShortBufferException – if there is insufficient space in the output buffer
Returns:	the number of bytes stored in `output`
Since:	1.5
Params:	output – the buffer for the result outputOffset – the offset in `output` where the result is stored
Throws:	IllegalStateException – if this cipher is in a wrong state (e.g., has not been initialized) IllegalBlockSizeException – if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided. ShortBufferException – if the given output buffer is too small to hold the result BadPaddingException – if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes AEADBadTagException – if this cipher is decrypting in an AEAD mode (such as GCM/CCM), and the received authentication tag does not match the calculated value
Returns:	the number of bytes stored in `output`
Params:	key – the key to be wrapped.
Throws:	IllegalStateException – if this cipher is in a wrong state (e.g., has not been initialized). IllegalBlockSizeException – if this cipher is a block cipher, no padding has been requested, and the length of the encoding of the key to be wrapped is not a multiple of the block size. InvalidKeyException – if it is impossible or unsafe to wrap the key with this cipher (e.g., a hardware protected key is being passed to a software-only cipher). UnsupportedOperationException – if the corresponding method in the `CipherSpi` is not supported.
Returns:	the wrapped key.
Params:	wrappedKey – the key to be unwrapped. wrappedKeyAlgorithm – the algorithm associated with the wrapped key. wrappedKeyType – the type of the wrapped key. This must be one of `SECRET_KEY`, `PRIVATE_KEY`, or `PUBLIC_KEY`.
Throws:	IllegalStateException – if this cipher is in a wrong state (e.g., has not been initialized). NoSuchAlgorithmException – if no installed providers can create keys of type `wrappedKeyType` for the `wrappedKeyAlgorithm`. InvalidKeyException – if `wrappedKey` does not represent a wrapped key of type `wrappedKeyType` for the `wrappedKeyAlgorithm`. UnsupportedOperationException – if the corresponding method in the `CipherSpi` is not supported.
Returns:	the unwrapped key.
Params:	transformation – the cipher transformation.
Throws:	NullPointerException – if `transformation` is null. NoSuchAlgorithmException – if `transformation` is not a valid transformation, i.e. in the form of "algorithm" or "algorithm/mode/padding".
Returns:	the maximum key length in bits or Integer.MAX_VALUE.
Since:	1.5
Params:	src – the buffer containing the Additional Authentication Data
Throws:	IllegalArgumentException – if the `src` byte array is null IllegalStateException – if this cipher is in a wrong state (e.g., has not been initialized), does not accept AAD, or if operating in either GCM or CCM mode and one of the `update` methods has already been called for the active encryption/decryption operation UnsupportedOperationException – if the corresponding method in the `CipherSpi` has not been overridden by an implementation
Since:	1.7
Params:	src – the buffer containing the AAD offset – the offset in `src` where the AAD input starts len – the number of AAD bytes
Throws:	IllegalArgumentException – if the `src` byte array is null, or the `offset` or `length` is less than 0, or the sum of the `offset` and `len` is greater than the length of the `src` byte array IllegalStateException – if this cipher is in a wrong state (e.g., has not been initialized), does not accept AAD, or if operating in either GCM or CCM mode and one of the `update` methods has already been called for the active encryption/decryption operation UnsupportedOperationException – if the corresponding method in the `CipherSpi` has not been overridden by an implementation
Since:	1.7
Params:	src – the buffer containing the AAD
Throws:	IllegalArgumentException – if the `src ByteBuffer` is null IllegalStateException – if this cipher is in a wrong state (e.g., has not been initialized), does not accept AAD, or if operating in either GCM or CCM mode and one of the `update` methods has already been called for the active encryption/decryption operation UnsupportedOperationException – if the corresponding method in the `CipherSpi` has not been overridden by an implementation
Since:	1.7
/

java/ 11/ java.base/javax/crypto/Cipher.java
