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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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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 * 2 along with this work; if not, write to the Free Software Foundation,
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package sun.security.provider.certpath;

import java.io.IOException;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.PublicKey;
import java.security.cert.X509Certificate;
import java.util.Arrays;
import javax.security.auth.x500.X500Principal;
import sun.security.util.HexDumpEncoder;
import sun.security.x509.*;
import sun.security.util.*;

This class corresponds to the CertId field in OCSP Request
and the OCSP Response. The ASN.1 definition for CertID is defined
in RFC 2560 as:
CertID          ::=     SEQUENCE {
     hashAlgorithm       AlgorithmIdentifier,
     issuerNameHash      OCTET STRING, -- Hash of Issuer's DN
     issuerKeyHash       OCTET STRING, -- Hash of Issuers public key
     serialNumber        CertificateSerialNumber
     }

Author:
     Ram Marti/**
 * This class corresponds to the CertId field in OCSP Request
 * and the OCSP Response. The ASN.1 definition for CertID is defined
 * in RFC 2560 as:
 * <pre>
 *
 * CertID          ::=     SEQUENCE {
 *      hashAlgorithm       AlgorithmIdentifier,
 *      issuerNameHash      OCTET STRING, -- Hash of Issuer's DN
 *      issuerKeyHash       OCTET STRING, -- Hash of Issuers public key
 *      serialNumber        CertificateSerialNumber
 *      }
 *
 * </pre>
 *
 * @author      Ram Marti
 */

public class CertId {

    private static final boolean debug = false;
    private static final AlgorithmId SHA1_ALGID
        = new AlgorithmId(AlgorithmId.SHA_oid);
    private final AlgorithmId hashAlgId;
    private final byte[] issuerNameHash;
    private final byte[] issuerKeyHash;
    private final SerialNumber certSerialNumber;
    private int myhash = -1; // hashcode for this CertId

    
Creates a CertId. The hash algorithm used is SHA-1.
/**
     * Creates a CertId. The hash algorithm used is SHA-1.
     */
    public CertId(X509Certificate issuerCert, SerialNumber serialNumber)
        throws IOException {

        this(issuerCert.getSubjectX500Principal(),
             issuerCert.getPublicKey(), serialNumber);
    }

    public CertId(X500Principal issuerName, PublicKey issuerKey,
                  SerialNumber serialNumber) throws IOException {

        // compute issuerNameHash
        MessageDigest md = null;
        try {
            md = MessageDigest.getInstance("SHA1");
        } catch (NoSuchAlgorithmException nsae) {
            throw new IOException("Unable to create CertId", nsae);
        }
        hashAlgId = SHA1_ALGID;
        md.update(issuerName.getEncoded());
        issuerNameHash = md.digest();

        // compute issuerKeyHash (remove the tag and length)
        byte[] pubKey = issuerKey.getEncoded();
        DerValue val = new DerValue(pubKey);
        DerValue[] seq = new DerValue[2];
        seq[0] = val.data.getDerValue(); // AlgorithmID
        seq[1] = val.data.getDerValue(); // Key
        byte[] keyBytes = seq[1].getBitString();
        md.update(keyBytes);
        issuerKeyHash = md.digest();
        certSerialNumber = serialNumber;

        if (debug) {
            HexDumpEncoder encoder = new HexDumpEncoder();
            System.out.println("Issuer Name is " + issuerName);
            System.out.println("issuerNameHash is " +
                encoder.encodeBuffer(issuerNameHash));
            System.out.println("issuerKeyHash is " +
                encoder.encodeBuffer(issuerKeyHash));
            System.out.println("SerialNumber is " + serialNumber.getNumber());
        }
    }

    
Creates a CertId from its ASN.1 DER encoding.
/**
     * Creates a CertId from its ASN.1 DER encoding.
     */
    public CertId(DerInputStream derIn) throws IOException {
        hashAlgId = AlgorithmId.parse(derIn.getDerValue());
        issuerNameHash = derIn.getOctetString();
        issuerKeyHash = derIn.getOctetString();
        certSerialNumber = new SerialNumber(derIn);
    }

    
Return the hash algorithm identifier.
/**
     * Return the hash algorithm identifier.
     */
    public AlgorithmId getHashAlgorithm() {
        return hashAlgId;
    }

    
Return the hash value for the issuer name.
/**
     * Return the hash value for the issuer name.
     */
    public byte[] getIssuerNameHash() {
        return issuerNameHash;
    }

    
Return the hash value for the issuer key.
/**
     * Return the hash value for the issuer key.
     */
    public byte[] getIssuerKeyHash() {
        return issuerKeyHash;
    }

    
Return the serial number.
/**
     * Return the serial number.
     */
    public BigInteger getSerialNumber() {
        return certSerialNumber.getNumber();
    }

    
Encode the CertId using ASN.1 DER.
The hash algorithm used is SHA-1.
/**
     * Encode the CertId using ASN.1 DER.
     * The hash algorithm used is SHA-1.
     */
    public void encode(DerOutputStream out) throws IOException {

        DerOutputStream tmp = new DerOutputStream();
        hashAlgId.encode(tmp);
        tmp.putOctetString(issuerNameHash);
        tmp.putOctetString(issuerKeyHash);
        certSerialNumber.encode(tmp);
        out.write(DerValue.tag_Sequence, tmp);

        if (debug) {
            HexDumpEncoder encoder = new HexDumpEncoder();
            System.out.println("Encoded certId is " +
                encoder.encode(out.toByteArray()));
        }
    }

   
Returns a hashcode value for this CertId.
Returns:
the hashcode value./**
     * Returns a hashcode value for this CertId.
     *
     * @return the hashcode value.
     */
    @Override public int hashCode() {
        if (myhash == -1) {
            myhash = hashAlgId.hashCode();
            for (int i = 0; i < issuerNameHash.length; i++) {
                myhash += issuerNameHash[i] * i;
            }
            for (int i = 0; i < issuerKeyHash.length; i++) {
                myhash += issuerKeyHash[i] * i;
            }
            myhash += certSerialNumber.getNumber().hashCode();
        }
        return myhash;
    }

    
Compares this CertId for equality with the specified
object. Two CertId objects are considered equal if their hash algorithms,
their issuer name and issuer key hash values and their serial numbers
are equal.
Params:
other – the object to test for equality with this object.
Returns:
true if the objects are considered equal, false otherwise./**
     * Compares this CertId for equality with the specified
     * object. Two CertId objects are considered equal if their hash algorithms,
     * their issuer name and issuer key hash values and their serial numbers
     * are equal.
     *
     * @param other the object to test for equality with this object.
     * @return true if the objects are considered equal, false otherwise.
     */
    @Override public boolean equals(Object other) {
        if (this == other) {
            return true;
        }
        if (other == null || (!(other instanceof CertId))) {
            return false;
        }

        CertId that = (CertId) other;
        if (hashAlgId.equals(that.getHashAlgorithm()) &&
            Arrays.equals(issuerNameHash, that.getIssuerNameHash()) &&
            Arrays.equals(issuerKeyHash, that.getIssuerKeyHash()) &&
            certSerialNumber.getNumber().equals(that.getSerialNumber())) {
            return true;
        } else {
            return false;
        }
    }

    
Create a string representation of the CertId.
/**
     * Create a string representation of the CertId.
     */
    @Override public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("CertId \n");
        sb.append("Algorithm: " + hashAlgId.toString() +"\n");
        sb.append("issuerNameHash \n");
        HexDumpEncoder encoder = new HexDumpEncoder();
        sb.append(encoder.encode(issuerNameHash));
        sb.append("\nissuerKeyHash: \n");
        sb.append(encoder.encode(issuerKeyHash));
        sb.append("\n" +  certSerialNumber.toString());
        return sb.toString();
    }
}