Java example source code file (KeyImpl.java)

This example Java source code file (KeyImpl.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

asn1exception, classnotfoundexception, crypto, des, empty, encryptionkey, hexdumpencoder, illegalstateexception, ioexception, keyimpl, principalname, secretkey, serializable, string, this, util

The KeyImpl.java Java example source code

/*
 * Copyright (c) 2000, 2013, 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.auth.kerberos;

import java.io.*;
import java.util.Arrays;
import javax.crypto.SecretKey;
import javax.security.auth.Destroyable;
import javax.security.auth.DestroyFailedException;
import sun.misc.HexDumpEncoder;
import sun.security.krb5.Asn1Exception;
import sun.security.krb5.PrincipalName;
import sun.security.krb5.EncryptionKey;
import sun.security.krb5.EncryptedData;
import sun.security.krb5.KrbException;
import sun.security.krb5.KrbCryptoException;
import sun.security.util.DerValue;

/**
 * This class encapsulates a Kerberos encryption key. It is not associated
 * with a principal and may represent an ephemeral session key.
 *
 * @author Mayank Upadhyay
 * @since 1.4
 *
 * @serial include
 */
class KeyImpl implements SecretKey, Destroyable, Serializable {

    private static final long serialVersionUID = -7889313790214321193L;

    private transient byte[] keyBytes;
    private transient int keyType;
    private transient volatile boolean destroyed = false;


    /**
     * Constructs a KeyImpl from the given bytes.
     *
     * @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.
     */
    public KeyImpl(byte[] keyBytes,
                       int keyType) {
        this.keyBytes = keyBytes.clone();
        this.keyType = keyType;
    }

    /**
     * Constructs a KeyImpl from a password.
     *
     * @param principal the principal from which to derive the salt
     * @param password the password that should be used to compute the
     * key.
     * @param algorithm the name for the algorithm that this key wil be
     * used for. This parameter may be null in which case "DES" will be
     * assumed.
     */
    public KeyImpl(KerberosPrincipal principal,
                   char[] password,
                   String algorithm) {

        try {
            PrincipalName princ = new PrincipalName(principal.getName());
            EncryptionKey key =
                new EncryptionKey(password, princ.getSalt(), algorithm);
            this.keyBytes = key.getBytes();
            this.keyType = key.getEType();
        } catch (KrbException e) {
            throw new IllegalArgumentException(e.getMessage());
        }
    }

    /**
     * Returns the keyType for this key as defined in the Kerberos Spec.
     */
    public final int getKeyType() {
        if (destroyed)
            throw new IllegalStateException("This key is no longer valid");
        return keyType;
    }

    /*
     * Methods from java.security.Key
     */

    public final String getAlgorithm() {
        return getAlgorithmName(keyType);
    }

    private String getAlgorithmName(int eType) {
        if (destroyed)
            throw new IllegalStateException("This key is no longer valid");

        switch (eType) {
        case EncryptedData.ETYPE_DES_CBC_CRC:
        case EncryptedData.ETYPE_DES_CBC_MD5:
            return "DES";

        case EncryptedData.ETYPE_DES3_CBC_HMAC_SHA1_KD:
            return "DESede";

        case EncryptedData.ETYPE_ARCFOUR_HMAC:
            return "ArcFourHmac";

        case EncryptedData.ETYPE_AES128_CTS_HMAC_SHA1_96:
            return "AES128";

        case EncryptedData.ETYPE_AES256_CTS_HMAC_SHA1_96:
            return "AES256";

        case EncryptedData.ETYPE_NULL:
            return "NULL";

        default:
            throw new IllegalArgumentException(
                "Unsupported encryption type: " + eType);
        }
    }

    public final String getFormat() {
        if (destroyed)
            throw new IllegalStateException("This key is no longer valid");
        return "RAW";
    }

    public final byte[] getEncoded() {
        if (destroyed)
            throw new IllegalStateException("This key is no longer valid");
        return keyBytes.clone();
    }

    public void destroy() throws DestroyFailedException {
        if (!destroyed) {
            destroyed = true;
            Arrays.fill(keyBytes, (byte) 0);
        }
    }

    public boolean isDestroyed() {
        return destroyed;
    }

    /**
     * @serialData this {@code KeyImpl} is serialized by
     * writing out the ASN1 Encoded bytes of the encryption key.
     * The ASN1 encoding is defined in RFC4120 and as  follows:
     * EncryptionKey   ::= SEQUENCE {
     *          keytype    [0] Int32 -- actually encryption type --,
     *          keyvalue   [1] OCTET STRING
     * }
     */
    private void writeObject(ObjectOutputStream ois)
                throws IOException {
        if (destroyed) {
           throw new IOException("This key is no longer valid");
        }

        try {
           ois.writeObject((new EncryptionKey(keyType, keyBytes)).asn1Encode());
        } catch (Asn1Exception ae) {
           throw new IOException(ae.getMessage());
        }
    }

    private void readObject(ObjectInputStream ois)
                throws IOException, ClassNotFoundException {
        try {
            EncryptionKey encKey = new EncryptionKey(new
                                     DerValue((byte[])ois.readObject()));
            keyType = encKey.getEType();
            keyBytes = encKey.getBytes();
        } catch (Asn1Exception ae) {
            throw new IOException(ae.getMessage());
        }
    }

    public String toString() {
        HexDumpEncoder hd = new HexDumpEncoder();
        return "EncryptionKey: keyType=" + keyType
                          + " keyBytes (hex dump)="
                          + (keyBytes == null || keyBytes.length == 0 ?
                             " Empty Key" :
                             '\n' + hd.encodeBuffer(keyBytes)
                          + '\n');


    }

    public int hashCode() {
        int result = 17;
        if(isDestroyed()) {
            return result;
        }
        result = 37 * result + Arrays.hashCode(keyBytes);
        return 37 * result + keyType;
    }

    public boolean equals(Object other) {

        if (other == this)
            return true;

        if (! (other instanceof KeyImpl)) {
            return false;
        }

        KeyImpl otherKey = ((KeyImpl) other);
        if (isDestroyed() || otherKey.isDestroyed()) {
            return false;
        }

        if(keyType != otherKey.getKeyType() ||
                !Arrays.equals(keyBytes, otherKey.getEncoded())) {
            return false;
        }

        return true;
    }
}