/*
 * =============================================================================
 * 
 *   Copyright (c) 2007-2010, The JASYPT team (http://www.jasypt.org)
 * 
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 * 
 *       http://www.apache.org/licenses/LICENSE-2.0
 * 
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 * 
 * =============================================================================
 */
package org.jasypt.util.password;

import java.security.Provider;

import org.jasypt.digest.StandardByteDigester;
import org.jasypt.digest.StandardStringDigester;
import org.jasypt.digest.config.DigesterConfig;


Utility class for easily performing password digesting and checking.

 This class internally holds a StandardStringDigester which can be configured by the user by optionally choosing the algorithm to be used, the output format (BASE64 or hexadecimal) the mechanism of encryption (plain digests vs. use of random salt and iteration count (default)) and even use a DigesterConfig object for more advanced configuration. 

The results obtained when encoding with this class are encoded in
BASE64 form.


The required steps to use it are:

  
Create an instance (using new).
  
Configure if needed with the setX() methods.
  
Perform the desired encryptPassword(String) or 
      checkPassword(String, String) 
      operations.
 
 


This class is thread-safe

Author:
Daniel Fernández
Since:
1.2/**
 * <p>
 * Utility class for easily performing password digesting and checking.
 * </p>
 * <p>
 * This class internally holds a {@link StandardStringDigester}
 * which can be configured by the user by optionally choosing the algorithm 
 * to be used, the output format (BASE64 or hexadecimal) the mechanism of 
 * encryption (plain digests vs. use of random salt
 * and iteration count (default)) and even use a {@link DigesterConfig} object for
 * more advanced configuration.
 * </p>
 * <p>
 * The results obtained when encoding with this class are encoded in
 * BASE64 form.
 * </p>
 * <p>
 * The required steps to use it are:
 * <ol>
 *   <li>Create an instance (using <tt>new</tt>).</li>
 *   <li>Configure if needed with the <tt>setX()</tt> methods.</li>
 *   <li>Perform the desired <tt>{@link #encryptPassword(String)}</tt> or 
 *       <tt>{@link #checkPassword(String, String)}</tt> 
 *       operations.</li> 
 * </ol> 
 * </p>
 * <p>
 * This class is <i>thread-safe</i>
 * </p>
 * 
 * @since 1.2
 * 
 * @author Daniel Fern&aacute;ndez
 * 
 */
public final class ConfigurablePasswordEncryptor implements PasswordEncryptor {

    // The internal digester used
    private final StandardStringDigester digester;
    
    
    
Creates a new instance of ConfigurablePasswordEncryptor
/**
     * Creates a new instance of <tt>ConfigurablePasswordEncryptor</tt>
     *
     */
    public ConfigurablePasswordEncryptor() {
        super();
        this.digester = new StandardStringDigester();
    }


    
Lets the user configure this encryptor with a DigesterConfig object, like if he/she were using a StandardStringDigester object directly. 
Params:
config – the DigesterConfig object to be set for configuration.
See Also:
StandardStringDigester.setConfig(DigesterConfig)/**
     * Lets the user configure this encryptor with a {@link DigesterConfig}
     * object, like if he/she were using a {@link StandardStringDigester} object
     * directly.
     * 
     * @param config the DigesterConfig object to be set for configuration.
     * @see StandardStringDigester#setConfig(DigesterConfig)
     */
    public void setConfig(final DigesterConfig config) {
        this.digester.setConfig(config);
    }


    

Sets the algorithm to be used for digesting, like MD5 
or SHA-1.


This algorithm has to be supported by your security infrastructure, and
it should be allowed as an algorithm for creating
java.security.MessageDigest instances.

 If you are specifying a security provider with setProvider(Provider) or setProviderName(String), this algorithm should be supported by your specified provider. 

If you are not specifying a provider, you will be able to use those
algorithms provided by the default security provider of your JVM vendor.
For valid names in the Sun JVM, see Java 
        Cryptography Architecture API Specification & 
        Reference.

Params:
algorithm – the name of the algorithm to be used.
See Also:
StandardStringDigester.setAlgorithm(String)/**
     * <p>
     * Sets the algorithm to be used for digesting, like <tt>MD5</tt> 
     * or <tt>SHA-1</tt>.
     * </p>
     * <p>
     * This algorithm has to be supported by your security infrastructure, and
     * it should be allowed as an algorithm for creating
     * java.security.MessageDigest instances.
     * </p>
     * <p>
     * If you are specifying a security provider with {@link #setProvider(Provider)} or
     * {@link #setProviderName(String)}, this algorithm should be
     * supported by your specified provider.
     * </p>
     * <p>
     * If you are not specifying a provider, you will be able to use those
     * algorithms provided by the default security provider of your JVM vendor.
     * For valid names in the Sun JVM, see <a target="_blank" 
     *         href="http://java.sun.com/j2se/1.5.0/docs/guide/security/CryptoSpec.html#AppA">Java 
     *         Cryptography Architecture API Specification & 
     *         Reference</a>.
     * </p>
     * 
     * @param algorithm the name of the algorithm to be used.
     * @see StandardStringDigester#setAlgorithm(String)
     */
    public void setAlgorithm(final String algorithm) {
        this.digester.setAlgorithm(algorithm);
    }
    
    
    

Sets the name of the security provider to be asked for the
digest algorithm. This security provider has to be registered beforehand
at the JVM security framework. 

 The provider can also be set with the setProvider(Provider) method, in which case it will not be necessary neither registering the provider beforehand, nor calling this setProviderName(String) method to specify a provider name. 
 Note that a call to setProvider(Provider) overrides any value set by this method. 

If no provider name / provider is explicitly set, the default JVM
provider will be used.

Params:
providerName – the name of the security provider to be asked
                    for the digest algorithm.
Throws:
AlreadyInitializedException – if it has already been initialized, this is, if encryptPassword(String) or checkPassword(String, String) have been called at least once.
Since:
1.3/**
     * <p>
     * Sets the name of the security provider to be asked for the
     * digest algorithm. This security provider has to be registered beforehand
     * at the JVM security framework. 
     * </p>
     * <p>
     * The provider can also be set with the {@link #setProvider(Provider)}
     * method, in which case it will not be necessary neither registering
     * the provider beforehand,
     * nor calling this {@link #setProviderName(String)} method to specify
     * a provider name.
     * </p>
     * <p>
     * Note that a call to {@link #setProvider(Provider)} overrides any value 
     * set by this method.
     * </p>
     * <p>
     * If no provider name / provider is explicitly set, the default JVM
     * provider will be used.
     * </p>
     * 
     * @since 1.3
     * 
     * @param providerName the name of the security provider to be asked
     *                     for the digest algorithm.
     * @throws AlreadyInitializedException if it has already been initialized,
     *         this is, if {@link #encryptPassword(String)} or
     *         {@link #checkPassword(String, String)} have been called at least
     *         once.
     */
    public void setProviderName(final String providerName) {
        this.digester.setProviderName(providerName);
    }
    
    
    

Sets the security provider to be asked for the digest algorithm.
The provider does not have to be registered at the security 
infrastructure beforehand, and its being used here will not result in
it being registered.

 If this method is called, calling setProviderName(String) becomes unnecessary. 

If no provider name / provider is explicitly set, the default JVM
provider will be used.

Params:
provider – the provider to be asked for the chosen algorithm
Throws:
AlreadyInitializedException – if it has already been initialized, this is, if encryptPassword(String) or checkPassword(String, String) have been called at least once.
Since:
1.3/**
     * <p>
     * Sets the security provider to be asked for the digest algorithm.
     * The provider does not have to be registered at the security 
     * infrastructure beforehand, and its being used here will not result in
     * it being registered.
     * </p>
     * <p>
     * If this method is called, calling {@link #setProviderName(String)}
     * becomes unnecessary.
     * </p>
     * <p>
     * If no provider name / provider is explicitly set, the default JVM
     * provider will be used.
     * </p>
     * 
     * @since 1.3
     * 
     * @param provider the provider to be asked for the chosen algorithm
     * @throws AlreadyInitializedException if it has already been initialized,
     *         this is, if {@link #encryptPassword(String)} or
     *         {@link #checkPassword(String, String)} have been called at least
     *         once.
     */
    public void setProvider(final Provider provider) {
        this.digester.setProvider(provider);
    }
    

    
Lets the user specify if he/she wants a plain digest used as an encryption mechanism (no salt or iterations, as with MessageDigest), or rather use the jasypt's usual stronger mechanism for password encryption (based on the use of a salt and the iteration of the hash function). 
Params:
plainDigest – true for using plain digests, false for the strong
       salt and iteration count based mechanism./**
     * Lets the user specify if he/she wants a plain digest used as an
     * encryption mechanism (no salt or iterations, as with 
     * {@link java.security.MessageDigest}), or rather use the
     * jasypt's usual stronger mechanism for password encryption (based
     * on the use of a salt and the iteration of the hash function).
     * 
     * @param plainDigest true for using plain digests, false for the strong
     *        salt and iteration count based mechanism.
     */
    public void setPlainDigest(final boolean plainDigest) {
        if (plainDigest) {
            this.digester.setIterations(1);
            this.digester.setSaltSizeBytes(0);
        } else {
            this.digester.setIterations(StandardByteDigester.DEFAULT_ITERATIONS);
            this.digester.setSaltSizeBytes(StandardByteDigester.DEFAULT_SALT_SIZE_BYTES);
        }
    }

    
    

Sets the the form in which String output
will be encoded. Available encoding types are:


  
base64 (default)
  
hexadecimal

Params:
stringOutputType – the string output type.
Since:
1.3/**
     * <p>
     * Sets the the form in which String output
     * will be encoded. Available encoding types are:
     * </p>
     * <ul>
     *   <li><tt><b>base64</b></tt> (default)</li>
     *   <li><tt><b>hexadecimal</b></tt></li>
     * </ul>
     * @since 1.3
     * 
     * @param stringOutputType the string output type.
     */
    public void setStringOutputType(final String stringOutputType) {
        this.digester.setStringOutputType(stringOutputType);
    }
    
    
    
Encrypts (digests) a password.
Params:
password – the password to be encrypted.
See Also:
StandardStringDigester.digest(String)
Returns:
the resulting digest./**
     * Encrypts (digests) a password.
     * 
     * @param password the password to be encrypted.
     * @return the resulting digest.
     * @see StandardStringDigester#digest(String)
     */
    public String encryptPassword(final String password) {
        return this.digester.digest(password);
    }

    
    
Checks an unencrypted (plain) password against an encrypted one
(a digest) to see if they match.
Params:
plainPassword – the plain password to check.
encryptedPassword – the digest against which to check the password.
See Also:
StandardStringDigester.matches(String, String)
Returns:
true if passwords match, false if not./**
     * Checks an unencrypted (plain) password against an encrypted one
     * (a digest) to see if they match.
     * 
     * @param plainPassword the plain password to check.
     * @param encryptedPassword the digest against which to check the password.
     * @return true if passwords match, false if not.
     * @see StandardStringDigester#matches(String, String)
     */
    public boolean checkPassword(final String plainPassword, 
            final String encryptedPassword) {
        return this.digester.matches(plainPassword, encryptedPassword);
    }
    
}