| /* |
| * Copyright (c) 1997, 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 com.sun.crypto.provider; |
| |
| import java.security.SecureRandom; |
| import java.security.InvalidParameterException; |
| import java.security.InvalidAlgorithmParameterException; |
| import java.security.InvalidKeyException; |
| import java.security.spec.AlgorithmParameterSpec; |
| import javax.crypto.KeyGeneratorSpi; |
| import javax.crypto.SecretKey; |
| import javax.crypto.spec.DESKeySpec; |
| |
| /** |
| * This class generates a DES key. |
| * |
| * @author Jan Luehe |
| * |
| */ |
| |
| public final class DESKeyGenerator extends KeyGeneratorSpi { |
| |
| private SecureRandom random = null; |
| |
| /** |
| * Empty constructor |
| */ |
| public DESKeyGenerator() { |
| } |
| |
| /** |
| * Initializes this key generator. |
| * |
| * @param random the source of randomness for this generator |
| */ |
| protected void engineInit(SecureRandom random) { |
| this.random = random; |
| } |
| |
| /** |
| * Initializes this key generator with the specified parameter |
| * set and a user-provided source of randomness. |
| * |
| * @param params the key generation parameters |
| * @param random the source of randomness for this key generator |
| * |
| * @exception InvalidAlgorithmParameterException if <code>params</code> is |
| * inappropriate for this key generator |
| */ |
| protected void engineInit(AlgorithmParameterSpec params, |
| SecureRandom random) |
| throws InvalidAlgorithmParameterException { |
| throw new InvalidAlgorithmParameterException |
| ("DES key generation does not take any parameters"); |
| } |
| |
| /** |
| * Initializes this key generator for a certain keysize, using the given |
| * source of randomness. |
| * |
| * @param keysize the keysize. This is an algorithm-specific |
| * metric specified in number of bits. |
| * @param random the source of randomness for this key generator |
| */ |
| protected void engineInit(int keysize, SecureRandom random) { |
| if (keysize != 56) { |
| throw new InvalidParameterException("Wrong keysize: must " |
| + "be equal to 56"); |
| } |
| this.engineInit(random); |
| } |
| |
| /** |
| * Generates the DES key. |
| * |
| * @return the new DES key |
| */ |
| protected SecretKey engineGenerateKey() { |
| DESKey desKey = null; |
| |
| if (this.random == null) { |
| this.random = SunJCE.getRandom(); |
| } |
| |
| try { |
| byte[] key = new byte[DESKeySpec.DES_KEY_LEN]; |
| do { |
| this.random.nextBytes(key); |
| setParityBit(key, 0); |
| } while (DESKeySpec.isWeak(key, 0)); |
| desKey = new DESKey(key); |
| } catch (InvalidKeyException e) { |
| // this is never thrown |
| } |
| |
| return desKey; |
| } |
| |
| /* |
| * Does parity adjustment, using bit in position 8 as the parity bit, |
| * for 8 key bytes, starting at <code>offset</code>. |
| * |
| * The 8 parity bits of a DES key are only used for sanity-checking |
| * of the key, to see if the key could actually be a key. If you check |
| * the parity of the quantity, and it winds up not having the correct |
| * parity, then you'll know something went wrong. |
| * |
| * A key that is not parity adjusted (e.g. e4e4e4e4e4e4e4e4) produces the |
| * same output as a key that is parity adjusted (e.g. e5e5e5e5e5e5e5e5), |
| * because it is the 56 bits of the DES key that are cryptographically |
| * significant/"effective" -- the other 8 bits are just used for parity |
| * checking. |
| */ |
| static void setParityBit(byte[] key, int offset) { |
| if (key == null) |
| return; |
| |
| for (int i = 0; i < DESKeySpec.DES_KEY_LEN; i++) { |
| int b = key[offset] & 0xfe; |
| b |= (Integer.bitCount(b) & 1) ^ 1; |
| key[offset++] = (byte)b; |
| } |
| } |
| } |