1 /* 2 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package javax.crypto.spec; 27 28 import java.security.InvalidKeyException; 29 30 /** 31 * This class specifies a DES key. 32 * 33 * @author Jan Luehe 34 * 35 * @since 1.4 36 */ 37 public class DESKeySpec implements java.security.spec.KeySpec { 38 39 /** 40 * The constant which defines the length of a DES key in bytes. 41 */ 42 public static final int DES_KEY_LEN = 8; 43 44 private byte[] key; 45 46 /* 47 * Weak/semi-weak keys copied from FIPS 74. 48 * 49 * "...The first 6 keys have duals different than themselves, hence 50 * each is both a key and a dual giving 12 keys with duals. The last 51 * four keys equal their duals, and are called self-dual keys..." 52 * 53 * 1. E001E001F101F101 01E001E001F101F1 54 * 2. FE1FFE1FFEOEFEOE 1FFE1FFEOEFEOEFE 55 * 3. E01FE01FF10EF10E 1FE01FEOOEF10EF1 56 * 4. 01FE01FE01FE01FE FE01FE01FE01FE01 57 * 5. 011F011F010E010E 1F011F010E010E01 58 * 6. E0FEE0FEF1FEF1FE FEE0FEE0FEF1FEF1 59 * 7. 0101010101010101 0101010101010101 60 * 8. FEFEFEFEFEFEFEFE FEFEFEFEFEFEFEFE 61 * 9. E0E0E0E0F1F1F1F1 E0E0E0E0F1F1F1F1 62 * 10. 1F1F1F1F0E0E0E0E 1F1F1F1F0E0E0E0E 63 */ 64 private static final byte[][] WEAK_KEYS = { 65 66 { (byte)0x01, (byte)0x01, (byte)0x01, (byte)0x01, (byte)0x01, 67 (byte)0x01, (byte)0x01, (byte)0x01 }, 68 69 { (byte)0xFE, (byte)0xFE, (byte)0xFE, (byte)0xFE, (byte)0xFE, 70 (byte)0xFE, (byte)0xFE, (byte)0xFE }, 71 72 { (byte)0x1F, (byte)0x1F, (byte)0x1F, (byte)0x1F, (byte)0x0E, 73 (byte)0x0E, (byte)0x0E, (byte)0x0E }, 74 75 { (byte)0xE0, (byte)0xE0, (byte)0xE0, (byte)0xE0, (byte)0xF1, 76 (byte)0xF1, (byte)0xF1, (byte)0xF1 }, 77 78 { (byte)0x01, (byte)0xFE, (byte)0x01, (byte)0xFE, (byte)0x01, 79 (byte)0xFE, (byte)0x01, (byte)0xFE }, 80 81 { (byte)0x1F, (byte)0xE0, (byte)0x1F, (byte)0xE0, (byte)0x0E, 82 (byte)0xF1, (byte)0x0E, (byte)0xF1 }, 83 84 { (byte)0x01, (byte)0xE0, (byte)0x01, (byte)0xE0, (byte)0x01, 85 (byte)0xF1, (byte)0x01, (byte)0xF1 }, 86 87 { (byte)0x1F, (byte)0xFE, (byte)0x1F, (byte)0xFE, (byte)0x0E, 88 (byte)0xFE, (byte)0x0E, (byte)0xFE }, 89 90 { (byte)0x01, (byte)0x1F, (byte)0x01, (byte)0x1F, (byte)0x01, 91 (byte)0x0E, (byte)0x01, (byte)0x0E }, 92 93 { (byte)0xE0, (byte)0xFE, (byte)0xE0, (byte)0xFE, (byte)0xF1, 94 (byte)0xFE, (byte)0xF1, (byte)0xFE }, 95 96 { (byte)0xFE, (byte)0x01, (byte)0xFE, (byte)0x01, (byte)0xFE, 97 (byte)0x01, (byte)0xFE, (byte)0x01 }, 98 99 { (byte)0xE0, (byte)0x1F, (byte)0xE0, (byte)0x1F, (byte)0xF1, 100 (byte)0x0E, (byte)0xF1, (byte)0x0E }, 101 102 { (byte)0xE0, (byte)0x01, (byte)0xE0, (byte)0x01, (byte)0xF1, 103 (byte)0x01, (byte)0xF1, (byte)0x01 }, 104 105 { (byte)0xFE, (byte)0x1F, (byte)0xFE, (byte)0x1F, (byte)0xFE, 106 (byte)0x0E, (byte)0xFE, (byte)0x0E }, 107 108 { (byte)0x1F, (byte)0x01, (byte)0x1F, (byte)0x01, (byte)0x0E, 109 (byte)0x01, (byte)0x0E, (byte)0x01 }, 110 111 { (byte)0xFE, (byte)0xE0, (byte)0xFE, (byte)0xE0, (byte)0xFE, 112 (byte)0xF1, (byte)0xFE, (byte)0xF1 } 113 }; 114 115 /** 116 * Creates a DESKeySpec object using the first 8 bytes in 117 * <code>key</code> as the key material for the DES key. 118 * 119 * <p> The bytes that constitute the DES key are those between 120 * <code>key[0]</code> and <code>key[7]</code> inclusive. 121 * 122 * @param key the buffer with the DES key material. The first 8 bytes 123 * of the buffer are copied to protect against subsequent modification. 124 * 125 * @exception NullPointerException if the given key material is 126 * <code>null</code> 127 * @exception InvalidKeyException if the given key material is shorter 128 * than 8 bytes. 129 */ DESKeySpec(byte[] key)130 public DESKeySpec(byte[] key) throws InvalidKeyException { 131 this(key, 0); 132 } 133 134 /** 135 * Creates a DESKeySpec object using the first 8 bytes in 136 * <code>key</code>, beginning at <code>offset</code> inclusive, 137 * as the key material for the DES key. 138 * 139 * <p> The bytes that constitute the DES key are those between 140 * <code>key[offset]</code> and <code>key[offset+7]</code> inclusive. 141 * 142 * @param key the buffer with the DES key material. The first 8 bytes 143 * of the buffer beginning at <code>offset</code> inclusive are copied 144 * to protect against subsequent modification. 145 * @param offset the offset in <code>key</code>, where the DES key 146 * material starts. 147 * 148 * @exception NullPointerException if the given key material is 149 * <code>null</code> 150 * @exception InvalidKeyException if the given key material, starting at 151 * <code>offset</code> inclusive, is shorter than 8 bytes. 152 */ DESKeySpec(byte[] key, int offset)153 public DESKeySpec(byte[] key, int offset) throws InvalidKeyException { 154 if (key.length - offset < DES_KEY_LEN) { 155 throw new InvalidKeyException("Wrong key size"); 156 } 157 this.key = new byte[DES_KEY_LEN]; 158 System.arraycopy(key, offset, this.key, 0, DES_KEY_LEN); 159 } 160 161 /** 162 * Returns the DES key material. 163 * 164 * @return the DES key material. Returns a new array 165 * each time this method is called. 166 */ getKey()167 public byte[] getKey() { 168 return this.key.clone(); 169 } 170 171 /** 172 * Checks if the given DES key material, starting at <code>offset</code> 173 * inclusive, is parity-adjusted. 174 * 175 * @param key the buffer with the DES key material. 176 * @param offset the offset in <code>key</code>, where the DES key 177 * material starts. 178 * 179 * @return true if the given DES key material is parity-adjusted, false 180 * otherwise. 181 * 182 * @exception InvalidKeyException if the given key material is 183 * <code>null</code>, or starting at <code>offset</code> inclusive, is 184 * shorter than 8 bytes. 185 */ isParityAdjusted(byte[] key, int offset)186 public static boolean isParityAdjusted(byte[] key, int offset) 187 throws InvalidKeyException { 188 if (key == null) { 189 throw new InvalidKeyException("null key"); 190 } 191 if (key.length - offset < DES_KEY_LEN) { 192 throw new InvalidKeyException("Wrong key size"); 193 } 194 195 for (int i = 0; i < DES_KEY_LEN; i++) { 196 int k = Integer.bitCount(key[offset++] & 0xff); 197 if ((k & 1) == 0) { 198 return false; 199 } 200 } 201 202 return true; 203 } 204 205 /** 206 * Checks if the given DES key material is weak or semi-weak. 207 * 208 * @param key the buffer with the DES key material. 209 * @param offset the offset in <code>key</code>, where the DES key 210 * material starts. 211 * 212 * @return true if the given DES key material is weak or semi-weak, false 213 * otherwise. 214 * 215 * @exception InvalidKeyException if the given key material is 216 * <code>null</code>, or starting at <code>offset</code> inclusive, is 217 * shorter than 8 bytes. 218 */ isWeak(byte[] key, int offset)219 public static boolean isWeak(byte[] key, int offset) 220 throws InvalidKeyException { 221 if (key == null) { 222 throw new InvalidKeyException("null key"); 223 } 224 if (key.length - offset < DES_KEY_LEN) { 225 throw new InvalidKeyException("Wrong key size"); 226 } 227 for (int i = 0; i < WEAK_KEYS.length; i++) { 228 boolean found = true; 229 for (int j = 0; j < DES_KEY_LEN && found == true; j++) { 230 if (WEAK_KEYS[i][j] != key[j+offset]) { 231 found = false; 232 } 233 } 234 if (found == true) { 235 return found; 236 } 237 } 238 return false; 239 } 240 } 241