Class Certificate

public abstract class Certificate
extends Object
implements Serializable

Abstract class for managing a variety of identity certificates. An identity certificate is a binding of a principal to a public key which is vouched for by 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.

Constructors

Certificate

protected Certificate(String type)

Creates a certificate of the specified type.

Parameters:

type - the standard name of the certificate type. See the CertificateFactory section in the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard certificate types.

Methods

getType

public final String getType()

Returns the type of this certificate.

Returns:

the type of this certificate.

equals

public boolean equals(Object other)

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.

Overrides:

equals in class Object

Parameters:

other - the object to test for equality with this certificate.

Returns:

true iff the encoded forms of the two certificates match, false otherwise.

See Also:

Object.hashCode(), HashMap

hashCode

public int hashCode()

Returns a hashcode value for this certificate from its encoded form.

Overrides:

hashCode in class Object

Returns:

the hashcode value.

See Also:

Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

getEncoded

public abstract byte[] getEncoded()
                           throws CertificateEncodingException

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.

Returns:

the encoded form of this certificate

Throws:

CertificateEncodingException - if an encoding error occurs.

verify

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.

Parameters:

key - the PublicKey used to carry out the verification.

Throws:

NoSuchAlgorithmException - on unsupported signature algorithms.

InvalidKeyException - on incorrect key.

NoSuchProviderException - if there's no default provider.

SignatureException - on signature errors.

CertificateException - on encoding errors.

verify

public abstract void verify(PublicKey key,
                            String sigProvider)
                     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.

Parameters:

key - the PublicKey used to carry out the verification.

sigProvider - the name of the signature provider.

Throws:

NoSuchAlgorithmException - on unsupported signature algorithms.

InvalidKeyException - on incorrect key.

NoSuchProviderException - on incorrect provider.

SignatureException - on signature errors.

CertificateException - on encoding errors.

verify

public void verify(PublicKey key,
                   Provider sigProvider)
            throws CertificateException,
                   NoSuchAlgorithmException,
                   InvalidKeyException,
                   SignatureException

Parameters:

key - the PublicKey used to carry out the verification.

sigProvider - the signature provider.

Throws:

NoSuchAlgorithmException - on unsupported signature algorithms.

InvalidKeyException - on incorrect key.

SignatureException - on signature errors.

CertificateException - on encoding errors.

UnsupportedOperationException - if the method is not supported

Since:

1.8

toString

public abstract String toString()

Returns a string representation of this certificate.

Overrides:

toString in class Object

Returns:

a string representation of this certificate.

getPublicKey

public abstract PublicKey getPublicKey()

Gets the public key from this certificate.

Returns:

the public key.

writeReplace

protected Object writeReplace()
                       throws ObjectStreamException

Replace the Certificate to be serialized.

Returns:

the alternate Certificate object to be serialized

Throws:

ObjectStreamException - if a new object representing this Certificate could not be created

Since:

1.3