1/* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18package javax.crypto.spec; 19 20import java.security.InvalidKeyException; 21import java.security.spec.KeySpec; 22 23/** 24 * The key specification for a triple-DES (DES-EDE) key. 25 */ 26public class DESedeKeySpec implements KeySpec { 27 28 /** 29 * The length of a DES-EDE key in bytes. 30 */ 31 public static final int DES_EDE_KEY_LEN = 24; 32 33 private final byte[] key; 34 35 /** 36 * Creates a new <code>DESedeKeySpec</code> instance from the first 24 ( 37 * {@link #DES_EDE_KEY_LEN}) bytes of the specified key data. 38 * 39 * @param key 40 * the key data. 41 * @throws InvalidKeyException 42 * if the length of the key data is less than 24. 43 * @throws NullPointerException 44 * if the key data is null. 45 */ 46 public DESedeKeySpec(byte[] key) throws InvalidKeyException { 47 if (key == null) { 48 throw new NullPointerException("key == null"); 49 } 50 if (key.length < DES_EDE_KEY_LEN) { 51 throw new InvalidKeyException(); 52 } 53 this.key = new byte[DES_EDE_KEY_LEN]; 54 System.arraycopy(key, 0, this.key, 0, DES_EDE_KEY_LEN); 55 } 56 57 /** 58 * Creates a new <code>DESedeKeySpec</code> instance from the first 24 ( 59 * {@link #DES_EDE_KEY_LEN} ) bytes of the specified key data starting at 60 * <code>offset</code>. 61 * 62 * @param key 63 * the key data 64 * @param offset 65 * the offset to start at. 66 * @throws InvalidKeyException 67 * if the length of the key data starting at offset is less than 68 * 24. 69 * @throws NullPointerException 70 * if the key data is null. 71 */ 72 public DESedeKeySpec(byte[] key, int offset) throws InvalidKeyException { 73 if (key == null) { 74 throw new NullPointerException("key == null"); 75 } 76 if (key.length - offset < DES_EDE_KEY_LEN) { 77 throw new InvalidKeyException(); 78 } 79 this.key = new byte[DES_EDE_KEY_LEN]; 80 System.arraycopy(key, offset, this.key, 0, DES_EDE_KEY_LEN); 81 } 82 83 /** 84 * Returns a copy of the key. 85 * 86 * @return a copy of the key. 87 */ 88 public byte[] getKey() { 89 byte[] result = new byte [DES_EDE_KEY_LEN]; 90 System.arraycopy(this.key, 0, result, 0, DES_EDE_KEY_LEN); 91 return result; 92 } 93 94 /** 95 * Returns whether the specified key data starting at <code>offset</code> is 96 * <i>parity-adjusted</i>. 97 * 98 * @param key 99 * the key data. 100 * @param offset 101 * the offset to start checking at. 102 * @return {@code true} if the specified key data is parity-adjusted, 103 * {@code false} otherwise. 104 * @throws InvalidKeyException 105 * if the length of the key data starting at offset is less than 106 * 24. 107 */ 108 public static boolean isParityAdjusted(byte[] key, int offset) throws InvalidKeyException { 109 if (key.length - offset < DES_EDE_KEY_LEN) { 110 throw new InvalidKeyException(); 111 } 112 for (int i=offset; i<DES_EDE_KEY_LEN+offset; i++) { 113 int b = key[i]; 114 if ((((b & 1) + ((b & 2) >> 1) + ((b & 4) >> 2) 115 + ((b & 8) >> 3) + ((b & 16) >> 4) + ((b & 32) >> 5) 116 + ((b & 64) >> 6)) & 1) == ((b & 128) >> 7)) { 117 return false; 118 } 119 } 120 return true; 121 } 122} 123