1 package org.bouncycastle.crypto.engines; 2 3 import org.bouncycastle.crypto.BlockCipher; 4 import org.bouncycastle.crypto.CipherParameters; 5 import org.bouncycastle.crypto.DataLengthException; 6 import org.bouncycastle.crypto.OutputLengthException; 7 import org.bouncycastle.crypto.params.KeyParameter; 8 import org.bouncycastle.crypto.params.RC2Parameters; 9 10 /** 11 * an implementation of RC2 as described in RFC 2268 12 * "A Description of the RC2(r) Encryption Algorithm" R. Rivest. 13 */ 14 public class RC2Engine 15 implements BlockCipher 16 { 17 // 18 // the values we use for key expansion (based on the digits of PI) 19 // 20 private static byte[] piTable = 21 { 22 (byte)0xd9, (byte)0x78, (byte)0xf9, (byte)0xc4, (byte)0x19, (byte)0xdd, (byte)0xb5, (byte)0xed, 23 (byte)0x28, (byte)0xe9, (byte)0xfd, (byte)0x79, (byte)0x4a, (byte)0xa0, (byte)0xd8, (byte)0x9d, 24 (byte)0xc6, (byte)0x7e, (byte)0x37, (byte)0x83, (byte)0x2b, (byte)0x76, (byte)0x53, (byte)0x8e, 25 (byte)0x62, (byte)0x4c, (byte)0x64, (byte)0x88, (byte)0x44, (byte)0x8b, (byte)0xfb, (byte)0xa2, 26 (byte)0x17, (byte)0x9a, (byte)0x59, (byte)0xf5, (byte)0x87, (byte)0xb3, (byte)0x4f, (byte)0x13, 27 (byte)0x61, (byte)0x45, (byte)0x6d, (byte)0x8d, (byte)0x9, (byte)0x81, (byte)0x7d, (byte)0x32, 28 (byte)0xbd, (byte)0x8f, (byte)0x40, (byte)0xeb, (byte)0x86, (byte)0xb7, (byte)0x7b, (byte)0xb, 29 (byte)0xf0, (byte)0x95, (byte)0x21, (byte)0x22, (byte)0x5c, (byte)0x6b, (byte)0x4e, (byte)0x82, 30 (byte)0x54, (byte)0xd6, (byte)0x65, (byte)0x93, (byte)0xce, (byte)0x60, (byte)0xb2, (byte)0x1c, 31 (byte)0x73, (byte)0x56, (byte)0xc0, (byte)0x14, (byte)0xa7, (byte)0x8c, (byte)0xf1, (byte)0xdc, 32 (byte)0x12, (byte)0x75, (byte)0xca, (byte)0x1f, (byte)0x3b, (byte)0xbe, (byte)0xe4, (byte)0xd1, 33 (byte)0x42, (byte)0x3d, (byte)0xd4, (byte)0x30, (byte)0xa3, (byte)0x3c, (byte)0xb6, (byte)0x26, 34 (byte)0x6f, (byte)0xbf, (byte)0xe, (byte)0xda, (byte)0x46, (byte)0x69, (byte)0x7, (byte)0x57, 35 (byte)0x27, (byte)0xf2, (byte)0x1d, (byte)0x9b, (byte)0xbc, (byte)0x94, (byte)0x43, (byte)0x3, 36 (byte)0xf8, (byte)0x11, (byte)0xc7, (byte)0xf6, (byte)0x90, (byte)0xef, (byte)0x3e, (byte)0xe7, 37 (byte)0x6, (byte)0xc3, (byte)0xd5, (byte)0x2f, (byte)0xc8, (byte)0x66, (byte)0x1e, (byte)0xd7, 38 (byte)0x8, (byte)0xe8, (byte)0xea, (byte)0xde, (byte)0x80, (byte)0x52, (byte)0xee, (byte)0xf7, 39 (byte)0x84, (byte)0xaa, (byte)0x72, (byte)0xac, (byte)0x35, (byte)0x4d, (byte)0x6a, (byte)0x2a, 40 (byte)0x96, (byte)0x1a, (byte)0xd2, (byte)0x71, (byte)0x5a, (byte)0x15, (byte)0x49, (byte)0x74, 41 (byte)0x4b, (byte)0x9f, (byte)0xd0, (byte)0x5e, (byte)0x4, (byte)0x18, (byte)0xa4, (byte)0xec, 42 (byte)0xc2, (byte)0xe0, (byte)0x41, (byte)0x6e, (byte)0xf, (byte)0x51, (byte)0xcb, (byte)0xcc, 43 (byte)0x24, (byte)0x91, (byte)0xaf, (byte)0x50, (byte)0xa1, (byte)0xf4, (byte)0x70, (byte)0x39, 44 (byte)0x99, (byte)0x7c, (byte)0x3a, (byte)0x85, (byte)0x23, (byte)0xb8, (byte)0xb4, (byte)0x7a, 45 (byte)0xfc, (byte)0x2, (byte)0x36, (byte)0x5b, (byte)0x25, (byte)0x55, (byte)0x97, (byte)0x31, 46 (byte)0x2d, (byte)0x5d, (byte)0xfa, (byte)0x98, (byte)0xe3, (byte)0x8a, (byte)0x92, (byte)0xae, 47 (byte)0x5, (byte)0xdf, (byte)0x29, (byte)0x10, (byte)0x67, (byte)0x6c, (byte)0xba, (byte)0xc9, 48 (byte)0xd3, (byte)0x0, (byte)0xe6, (byte)0xcf, (byte)0xe1, (byte)0x9e, (byte)0xa8, (byte)0x2c, 49 (byte)0x63, (byte)0x16, (byte)0x1, (byte)0x3f, (byte)0x58, (byte)0xe2, (byte)0x89, (byte)0xa9, 50 (byte)0xd, (byte)0x38, (byte)0x34, (byte)0x1b, (byte)0xab, (byte)0x33, (byte)0xff, (byte)0xb0, 51 (byte)0xbb, (byte)0x48, (byte)0xc, (byte)0x5f, (byte)0xb9, (byte)0xb1, (byte)0xcd, (byte)0x2e, 52 (byte)0xc5, (byte)0xf3, (byte)0xdb, (byte)0x47, (byte)0xe5, (byte)0xa5, (byte)0x9c, (byte)0x77, 53 (byte)0xa, (byte)0xa6, (byte)0x20, (byte)0x68, (byte)0xfe, (byte)0x7f, (byte)0xc1, (byte)0xad 54 }; 55 56 private static final int BLOCK_SIZE = 8; 57 58 private int[] workingKey; 59 private boolean encrypting; 60 61 private int[] generateWorkingKey( 62 byte[] key, 63 int bits) 64 { 65 int x; 66 int[] xKey = new int[128]; 67 68 for (int i = 0; i != key.length; i++) 69 { 70 xKey[i] = key[i] & 0xff; 71 } 72 73 // Phase 1: Expand input key to 128 bytes 74 int len = key.length; 75 76 if (len < 128) 77 { 78 int index = 0; 79 80 x = xKey[len - 1]; 81 82 do 83 { 84 x = piTable[(x + xKey[index++]) & 255] & 0xff; 85 xKey[len++] = x; 86 } 87 while (len < 128); 88 } 89 90 // Phase 2 - reduce effective key size to "bits" 91 len = (bits + 7) >> 3; 92 x = piTable[xKey[128 - len] & (255 >> (7 & -bits))] & 0xff; 93 xKey[128 - len] = x; 94 95 for (int i = 128 - len - 1; i >= 0; i--) 96 { 97 x = piTable[x ^ xKey[i + len]] & 0xff; 98 xKey[i] = x; 99 } 100 101 // Phase 3 - copy to newKey in little-endian order 102 int[] newKey = new int[64]; 103 104 for (int i = 0; i != newKey.length; i++) 105 { 106 newKey[i] = (xKey[2 * i] + (xKey[2 * i + 1] << 8)); 107 } 108 109 return newKey; 110 } 111 112 /** 113 * initialise a RC2 cipher. 114 * 115 * @param encrypting whether or not we are for encryption. 116 * @param params the parameters required to set up the cipher. 117 * @exception IllegalArgumentException if the params argument is 118 * inappropriate. 119 */ 120 public void init( 121 boolean encrypting, 122 CipherParameters params) 123 { 124 this.encrypting = encrypting; 125 126 if (params instanceof RC2Parameters) 127 { 128 RC2Parameters param = (RC2Parameters)params; 129 130 workingKey = generateWorkingKey(param.getKey(), 131 param.getEffectiveKeyBits()); 132 } 133 else if (params instanceof KeyParameter) 134 { 135 byte[] key = ((KeyParameter)params).getKey(); 136 137 workingKey = generateWorkingKey(key, key.length * 8); 138 } 139 else 140 { 141 throw new IllegalArgumentException("invalid parameter passed to RC2 init - " + params.getClass().getName()); 142 } 143 144 } 145 146 public void reset() 147 { 148 } 149 150 public String getAlgorithmName() 151 { 152 return "RC2"; 153 } 154 155 public int getBlockSize() 156 { 157 return BLOCK_SIZE; 158 } 159 160 public final int processBlock( 161 byte[] in, 162 int inOff, 163 byte[] out, 164 int outOff) 165 { 166 if (workingKey == null) 167 { 168 throw new IllegalStateException("RC2 engine not initialised"); 169 } 170 171 if ((inOff + BLOCK_SIZE) > in.length) 172 { 173 throw new DataLengthException("input buffer too short"); 174 } 175 176 if ((outOff + BLOCK_SIZE) > out.length) 177 { 178 throw new OutputLengthException("output buffer too short"); 179 } 180 181 if (encrypting) 182 { 183 encryptBlock(in, inOff, out, outOff); 184 } 185 else 186 { 187 decryptBlock(in, inOff, out, outOff); 188 } 189 190 return BLOCK_SIZE; 191 } 192 193 /** 194 * return the result rotating the 16 bit number in x left by y 195 */ 196 private int rotateWordLeft( 197 int x, 198 int y) 199 { 200 x &= 0xffff; 201 return (x << y) | (x >> (16 - y)); 202 } 203 204 private void encryptBlock( 205 byte[] in, 206 int inOff, 207 byte[] out, 208 int outOff) 209 { 210 int x76, x54, x32, x10; 211 212 x76 = ((in[inOff + 7] & 0xff) << 8) + (in[inOff + 6] & 0xff); 213 x54 = ((in[inOff + 5] & 0xff) << 8) + (in[inOff + 4] & 0xff); 214 x32 = ((in[inOff + 3] & 0xff) << 8) + (in[inOff + 2] & 0xff); 215 x10 = ((in[inOff + 1] & 0xff) << 8) + (in[inOff + 0] & 0xff); 216 217 for (int i = 0; i <= 16; i += 4) 218 { 219 x10 = rotateWordLeft(x10 + (x32 & ~x76) + (x54 & x76) + workingKey[i ], 1); 220 x32 = rotateWordLeft(x32 + (x54 & ~x10) + (x76 & x10) + workingKey[i+1], 2); 221 x54 = rotateWordLeft(x54 + (x76 & ~x32) + (x10 & x32) + workingKey[i+2], 3); 222 x76 = rotateWordLeft(x76 + (x10 & ~x54) + (x32 & x54) + workingKey[i+3], 5); 223 } 224 225 x10 += workingKey[x76 & 63]; 226 x32 += workingKey[x10 & 63]; 227 x54 += workingKey[x32 & 63]; 228 x76 += workingKey[x54 & 63]; 229 230 for (int i = 20; i <= 40; i += 4) 231 { 232 x10 = rotateWordLeft(x10 + (x32 & ~x76) + (x54 & x76) + workingKey[i ], 1); 233 x32 = rotateWordLeft(x32 + (x54 & ~x10) + (x76 & x10) + workingKey[i+1], 2); 234 x54 = rotateWordLeft(x54 + (x76 & ~x32) + (x10 & x32) + workingKey[i+2], 3); 235 x76 = rotateWordLeft(x76 + (x10 & ~x54) + (x32 & x54) + workingKey[i+3], 5); 236 } 237 238 x10 += workingKey[x76 & 63]; 239 x32 += workingKey[x10 & 63]; 240 x54 += workingKey[x32 & 63]; 241 x76 += workingKey[x54 & 63]; 242 243 for (int i = 44; i < 64; i += 4) 244 { 245 x10 = rotateWordLeft(x10 + (x32 & ~x76) + (x54 & x76) + workingKey[i ], 1); 246 x32 = rotateWordLeft(x32 + (x54 & ~x10) + (x76 & x10) + workingKey[i+1], 2); 247 x54 = rotateWordLeft(x54 + (x76 & ~x32) + (x10 & x32) + workingKey[i+2], 3); 248 x76 = rotateWordLeft(x76 + (x10 & ~x54) + (x32 & x54) + workingKey[i+3], 5); 249 } 250 251 out[outOff + 0] = (byte)x10; 252 out[outOff + 1] = (byte)(x10 >> 8); 253 out[outOff + 2] = (byte)x32; 254 out[outOff + 3] = (byte)(x32 >> 8); 255 out[outOff + 4] = (byte)x54; 256 out[outOff + 5] = (byte)(x54 >> 8); 257 out[outOff + 6] = (byte)x76; 258 out[outOff + 7] = (byte)(x76 >> 8); 259 } 260 261 private void decryptBlock( 262 byte[] in, 263 int inOff, 264 byte[] out, 265 int outOff) 266 { 267 int x76, x54, x32, x10; 268 269 x76 = ((in[inOff + 7] & 0xff) << 8) + (in[inOff + 6] & 0xff); 270 x54 = ((in[inOff + 5] & 0xff) << 8) + (in[inOff + 4] & 0xff); 271 x32 = ((in[inOff + 3] & 0xff) << 8) + (in[inOff + 2] & 0xff); 272 x10 = ((in[inOff + 1] & 0xff) << 8) + (in[inOff + 0] & 0xff); 273 274 for (int i = 60; i >= 44; i -= 4) 275 { 276 x76 = rotateWordLeft(x76, 11) - ((x10 & ~x54) + (x32 & x54) + workingKey[i+3]); 277 x54 = rotateWordLeft(x54, 13) - ((x76 & ~x32) + (x10 & x32) + workingKey[i+2]); 278 x32 = rotateWordLeft(x32, 14) - ((x54 & ~x10) + (x76 & x10) + workingKey[i+1]); 279 x10 = rotateWordLeft(x10, 15) - ((x32 & ~x76) + (x54 & x76) + workingKey[i ]); 280 } 281 282 x76 -= workingKey[x54 & 63]; 283 x54 -= workingKey[x32 & 63]; 284 x32 -= workingKey[x10 & 63]; 285 x10 -= workingKey[x76 & 63]; 286 287 for (int i = 40; i >= 20; i -= 4) 288 { 289 x76 = rotateWordLeft(x76, 11) - ((x10 & ~x54) + (x32 & x54) + workingKey[i+3]); 290 x54 = rotateWordLeft(x54, 13) - ((x76 & ~x32) + (x10 & x32) + workingKey[i+2]); 291 x32 = rotateWordLeft(x32, 14) - ((x54 & ~x10) + (x76 & x10) + workingKey[i+1]); 292 x10 = rotateWordLeft(x10, 15) - ((x32 & ~x76) + (x54 & x76) + workingKey[i ]); 293 } 294 295 x76 -= workingKey[x54 & 63]; 296 x54 -= workingKey[x32 & 63]; 297 x32 -= workingKey[x10 & 63]; 298 x10 -= workingKey[x76 & 63]; 299 300 for (int i = 16; i >= 0; i -= 4) 301 { 302 x76 = rotateWordLeft(x76, 11) - ((x10 & ~x54) + (x32 & x54) + workingKey[i+3]); 303 x54 = rotateWordLeft(x54, 13) - ((x76 & ~x32) + (x10 & x32) + workingKey[i+2]); 304 x32 = rotateWordLeft(x32, 14) - ((x54 & ~x10) + (x76 & x10) + workingKey[i+1]); 305 x10 = rotateWordLeft(x10, 15) - ((x32 & ~x76) + (x54 & x76) + workingKey[i ]); 306 } 307 308 out[outOff + 0] = (byte)x10; 309 out[outOff + 1] = (byte)(x10 >> 8); 310 out[outOff + 2] = (byte)x32; 311 out[outOff + 3] = (byte)(x32 >> 8); 312 out[outOff + 4] = (byte)x54; 313 out[outOff + 5] = (byte)(x54 >> 8); 314 out[outOff + 6] = (byte)x76; 315 out[outOff + 7] = (byte)(x76 >> 8); 316 } 317 } 318
