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package javax.security.cert;

import java.security.PublicKey;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.InvalidKeyException;
import java.security.SignatureException;


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.)


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).


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.

Note: The classes in the package javax.security.cert
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
java.security.cert.


Author:Hemma Prafullchandra
See Also:
Since:1.4
/**
 * <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 other object is an
instanceof Certificate, then
its encoded form is retrieved and compared with the
encoded form of this certificate.

Params:
  • other – the object to test for equality with this certificate.
Returns:true if the encoded forms of the two certificates
        match, false otherwise.
/**
     * 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.

Returns:the hashcode value.
/**
     * 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.

Throws:
Returns:encoded form of this certificate
/**
     * 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.

Params:
  • key – the PublicKey used to carry out the verification.
Throws:
/**
     * 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.

Params:
  • key – the PublicKey used to carry out the verification.
  • sigProvider – the name of the signature provider.
Throws:
/**
     * 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.

Returns:a string representation of this certificate.
/**
     * 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.

Returns:the public key.
/**
     * Gets the public key from this certificate.
     *
     * @return the public key.
     */
    public abstract PublicKey getPublicKey();
}