/*
* @(#)KerberosKey.java 1.20 06/04/21
*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.security.auth.kerberos;
import java.util.Arrays;
import javax.crypto.SecretKey;
import javax.security.auth.Destroyable;
import javax.security.auth.DestroyFailedException;
/**
* This class encapsulates a long term secret key for a Kerberos
* principal.<p>
*
* All Kerberos JAAS login modules that obtain a principal's password and
* generate the secret key from it should use this class. Where available,
* the login module might even read this secret key directly from a
* Kerberos "keytab". Sometimes, such as when authenticating a server in
* the absence of user-to-user authentication, the login module will store
* an instance of this class in the private credential set of a
* {@link javax.security.auth.Subject Subject} during the commit phase of the
* authentication process.<p>
*
* It might be necessary for the application to be granted a
* {@link javax.security.auth.PrivateCredentialPermission
* PrivateCredentialPermission} if it needs to access the KerberosKey
* instance from a Subject. This permission is not needed when the
* application depends on the default JGSS Kerberos mechanism to access the
* KerberosKey. In that case, however, the application will need an
* appropriate
* {@link javax.security.auth.kerberos.ServicePermission ServicePermission}.
*
* @author Mayank Upadhyay
* @version 1.20, 04/21/06
* @since 1.4
*/
public class KerberosKey implements SecretKey, Destroyable {
private static final long serialVersionUID = -4625402278148246993L;
/**
* The principal that this secret key belongs to.
*
* @serial
*/
private KerberosPrincipal principal;
/**
* the version number of this secret key
*
* @serial
*/
private int versionNum;
/**
* <code>KeyImpl</code> is serialized by writing out the ASN1 Encoded bytes
* of the encryption key. The ASN1 encoding is defined in
* RFC1510 and as follows:
* <pre>
* EncryptionKey ::= SEQUENCE {
* keytype[0] INTEGER,
* keyvalue[1] OCTET STRING
* }
* </pre>
*
* @serial
*/
private KeyImpl key;
private transient boolean destroyed = false;
/**
* Constructs a KerberosKey from the given bytes when the key type and
* key version number are known. This can be used when reading the secret
* key information from a Kerberos "keytab".
*
* @param principal the principal that this secret key belongs to
* @param keyBytes the raw bytes for the secret key
* @param keyType the key type for the secret key as defined by the
* Kerberos protocol specification.
* @param versionNum the version number of this secret key
*/
public KerberosKey(KerberosPrincipal principal,
byte[] keyBytes,
int keyType,
int versionNum) {
this.principal = principal;
this.versionNum = versionNum;
key = new KeyImpl(keyBytes, keyType);
}
/**
* Constructs a KerberosKey from a principal's password.
*
* @param principal the principal that this password belongs to
* @param password the password that should be used to compute the key
* @param algorithm the name for the algorithm that this key will be
* used for. This parameter may be null in which case the default
* algorithm "DES" will be assumed.
* @throws IllegalArgumentException if the name of the
* algorithm passed is unsupported.
*/
public KerberosKey(KerberosPrincipal principal,
char[] password,
String algorithm) {
this.principal = principal;
// Pass principal in for salt
key = new KeyImpl(principal, password, algorithm);
}
/**
* Returns the principal that this key belongs to.
*
* @return the principal this key belongs to.
*/
public final KerberosPrincipal getPrincipal() {
if (destroyed)
throw new IllegalStateException("This key is no longer valid");
return principal;
}
/**
* Returns the key version number.
*
* @return the key version number.
*/
public final int getVersionNumber() {
if (destroyed)
throw new IllegalStateException("This key is no longer valid");
return versionNum;
}
/**
* Returns the key type for this long-term key.
*
* @return the key type.
*/
public final int getKeyType() {
if (destroyed)
throw new IllegalStateException("This key is no longer valid");
return key.getKeyType();
}
/*
* Methods from java.security.Key
*/
/**
* Returns the standard algorithm name for this key. For
* example, "DES" would indicate that this key is a DES key.
* See Appendix A in the <a href=
* "../../../../../technotes/guides/security/crypto/CryptoSpec.html#AppA">
* Java Cryptography Architecture API Specification & Reference
* </a>
* for information about standard algorithm names.
*
* @return the name of the algorithm associated with this key.
*/
public final String getAlgorithm() {
if (destroyed)
throw new IllegalStateException("This key is no longer valid");
return key.getAlgorithm();
}
/**
* Returns the name of the encoding format for this secret key.
*
* @return the String "RAW"
*/
public final String getFormat() {
if (destroyed)
throw new IllegalStateException("This key is no longer valid");
return key.getFormat();
}
/**
* Returns the key material of this secret key.
*
* @return the key material
*/
public final byte[] getEncoded() {
if (destroyed)
throw new IllegalStateException("This key is no longer valid");
return key.getEncoded();
}
/**
* Destroys this key. A call to any of its other methods after this
* will cause an IllegalStateException to be thrown.
*
* @throws DestroyFailedException if some error occurs while destorying
* this key.
*/
public void destroy() throws DestroyFailedException {
if (!destroyed) {
key.destroy();
principal = null;
destroyed = true;
}
}
/** Determines if this key has been destroyed.*/
public boolean isDestroyed() {
return destroyed;
}
public String toString() {
if (destroyed) {
return "Destroyed Principal";
}
return "Kerberos Principal " + principal.toString() +
"Key Version " + versionNum +
"key " + key.toString();
}
/**
* Returns a hashcode for this KerberosKey.
*
* @return a hashCode() for the <code>KerberosKey</code>
* @since 1.6
*/
public int hashCode() {
int result = 17;
if (isDestroyed()) {
return result;
}
result = 37 * result + Arrays.hashCode(getEncoded());
result = 37 * result + getKeyType();
if (principal != null) {
result = 37 * result + principal.hashCode();
}
return result * 37 + versionNum;
}
/**
* Compares the specified Object with this KerberosKey for equality.
* Returns true if the given object is also a
* <code>KerberosKey</code> and the two
* <code>KerberosKey</code> instances are equivalent.
*
* @param other the Object to compare to
* @return true if the specified object is equal to this KerberosKey,
* false otherwise. NOTE: Returns false if either of the KerberosKey
* objects has been destroyed.
* @since 1.6
*/
public boolean equals(Object other) {
if (other == this)
return true;
if (! (other instanceof KerberosKey)) {
return false;
}
KerberosKey otherKey = ((KerberosKey) other);
if (isDestroyed() || otherKey.isDestroyed()) {
return false;
}
if (versionNum != otherKey.getVersionNumber() ||
getKeyType() != otherKey.getKeyType() ||
!Arrays.equals(getEncoded(), otherKey.getEncoded())) {
return false;
}
if (principal == null) {
if (otherKey.getPrincipal() != null) {
return false;
}
} else {
if (!principal.equals(otherKey.getPrincipal())) {
return false;
}
}
return true;
}
}
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