/* * Copyright (c) 1997, 2006, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * 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). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */  package javax.security.cert; import java.security.PublicKey;import java.security.NoSuchAlgorithmException;import java.security.NoSuchProviderException;import java.security.InvalidKeyException;import java.security.SignatureException; /** * <p>Abstract class for managing a variety of identity certificates. * An identity certificate is a guarantee by a principal that * a public key is that of another principal.  (A principal represents * an entity such as an individual user, a group, or a corporation.) *<p> * This class is an abstraction for certificates that have different * formats but important common uses.  For example, different types of * certificates, such as X.509 and PGP, share general certificate * functionality (like encoding and verifying) and * some types of information (like a public key). * <p> * X.509, PGP, and SDSI certificates can all be implemented by * subclassing the Certificate class, even though they contain different * sets of information, and they store and retrieve the information in * different ways. * * <p><em>Note: The classes in the package <code>javax.security.cert</code> * exist for compatibility with earlier versions of the * Java Secure Sockets Extension (JSSE). New applications should instead * use the standard Java SE certificate classes located in * <code>java.security.cert</code>.</em></p> * * @since 1.4 * @see X509Certificate * * @author Hemma Prafullchandra */public abstract class Certificate {     /**     * Compares this certificate for equality with the specified     * object. If the <code>other</code> object is an     * <code>instanceof</code> <code>Certificate</code>, then     * its encoded form is retrieved and compared with the     * encoded form of this certificate.     *     * @param other the object to test for equality with this certificate.     * @return true if the encoded forms of the two certificates     *         match, false otherwise.     */    public boolean equals(Object other) {        if (this == other)            return true;        if (!(other instanceof Certificate))            return false;        try {            byte[] thisCert = this.getEncoded();            byte[] otherCert = ((Certificate)other).getEncoded();             if (thisCert.length != otherCert.length)                return false;            for (int i = 0; i < thisCert.length; i++)                 if (thisCert[i] != otherCert[i])                     return false;            return true;        } catch (CertificateException e) {            return false;        }    }     /**     * Returns a hashcode value for this certificate from its     * encoded form.     *     * @return the hashcode value.     */    public int hashCode() {        int     retval = 0;        try {            byte[] certData = this.getEncoded();            for (int i = 1; i < certData.length; i++) {                 retval += certData[i] * i;            }            return (retval);        } catch (CertificateException e) {            return (retval);        }    }     /**     * Returns the encoded form of this certificate. It is     * assumed that each certificate type would have only a single     * form of encoding; for example, X.509 certificates would     * be encoded as ASN.1 DER.     *     * @return encoded form of this certificate     * @exception CertificateEncodingException on internal certificate     *            encoding failure     */    public abstract byte[] getEncoded() throws CertificateEncodingException;     /**     * Verifies that this certificate was signed using the     * private key that corresponds to the specified public key.     *     * @param key the PublicKey used to carry out the verification.     *     * @exception NoSuchAlgorithmException on unsupported signature     * algorithms.     * @exception InvalidKeyException on incorrect key.     * @exception NoSuchProviderException if there's no default provider.     * @exception SignatureException on signature errors.     * @exception CertificateException on encoding errors.     */    public abstract void verify(PublicKey key)        throws CertificateException, NoSuchAlgorithmException,        InvalidKeyException, NoSuchProviderException,        SignatureException;     /**     * Verifies that this certificate was signed using the     * private key that corresponds to the specified public key.     * This method uses the signature verification engine     * supplied by the specified provider.     *     * @param key the PublicKey used to carry out the verification.     * @param sigProvider the name of the signature provider.     * @exception NoSuchAlgorithmException on unsupported signature algorithms.     * @exception InvalidKeyException on incorrect key.     * @exception NoSuchProviderException on incorrect provider.     * @exception SignatureException on signature errors.     * @exception CertificateException on encoding errors.     */    public abstract void verify(PublicKey key, String sigProvider)        throws CertificateException, NoSuchAlgorithmException,        InvalidKeyException, NoSuchProviderException,        SignatureException;     /**     * Returns a string representation of this certificate.     *     * @return a string representation of this certificate.     */    public abstract String toString();     /**     * Gets the public key from this certificate.     *     * @return the public key.     */    public abstract PublicKey getPublicKey();}