lib/silccrypt/cast.c

   1 /* Modified for SILC. -Pekka */
   2
   3 /* This is an independent implementation of the encryption algorithm:   */
   4 /*                                                                      */
   5 /*         CAST-256 by Carlisle Adams of Entrust Tecnhologies           */
   6 /*                                                                      */
   7 /* which is a candidate algorithm in the Advanced Encryption Standard   */
   8 /* programme of the US National Institute of Standards and Technology.  */
   9 /*                                                                      */
  10 /* Copyright in this implementation is held by Dr B R Gladman but I     */
  11 /* hereby give permission for its free direct or derivative use subject */
  12 /* to acknowledgment of its origin and compliance with any conditions   */
  13 /* that the originators of the algorithm place on its exploitation.     */
  14 /*                                                                      */
  15 /* Dr Brian Gladman (gladman@seven77.demon.co.uk) 14th January 1999     */
  16
  17 /* Timing data for CAST-256 (cast.c)
  18
  19 Core timing without I/O endian conversion:
  20
  21 128 bit key:
  22 Key Setup:    4333 cycles
  23 Encrypt:       633 cycles =    40.4 mbits/sec
  24 Decrypt:       634 cycles =    40.4 mbits/sec
  25 Mean:          634 cycles =    40.4 mbits/sec
  26
  27 192 bit key:
  28 Key Setup:    4342 cycles
  29 Encrypt:       633 cycles =    40.4 mbits/sec
  30 Decrypt:       633 cycles =    40.4 mbits/sec
  31 Mean:          633 cycles =    40.4 mbits/sec
  32
  33 256 bit key:
  34 Key Setup:    4325 cycles
  35 Encrypt:       639 cycles =    40.1 mbits/sec
  36 Decrypt:       638 cycles =    40.1 mbits/sec
  37 Mean:          639 cycles =    40.1 mbits/sec
  38
  39 Full timing with I/O endian conversion:
  40
  41 128 bit key:
  42 Key Setup:    4294 cycles
  43 Encrypt:       678 cycles =    37.8 mbits/sec
  44 Decrypt:       669 cycles =    38.3 mbits/sec
  45 Mean:          674 cycles =    38.0 mbits/sec
  46
  47 192 bit key:
  48 Key Setup:    4314 cycles
  49 Encrypt:       678 cycles =    37.8 mbits/sec
  50 Decrypt:       670 cycles =    38.2 mbits/sec
  51 Mean:          674 cycles =    38.0 mbits/sec
  52
  53 256 bit key:
  54 Key Setup:    4313 cycles
  55 Encrypt:       678 cycles =    37.8 mbits/sec
  56 Decrypt:       669 cycles =    38.3 mbits/sec
  57 Mean:          674 cycles =    38.0 mbits/sec
  58
  59 */
  60
  61 #include "silcincludes.h"
  62 #include "cast_internal.h"
  63 #include "cast.h"
  64
  65 #define io_swap
  66
  67 /*
  68  * SILC Crypto API for Cast-256
  69  */
  70
  71 /* Sets the key for the cipher. */
  72
  73 SILC_CIPHER_API_SET_KEY(cast)
  74 {
  75   SilcUInt32 k[8];
  76
  77   SILC_GET_WORD_KEY(key, k, keylen);
  78   cast_set_key((CastContext *)context, k, keylen);
  79
  80   return TRUE;
  81 }
  82
  83 /* Sets the string as a new key for the cipher. The string is first
  84    hashed and then used as a new key. */
  85
  86 SILC_CIPHER_API_SET_KEY_WITH_STRING(cast)
  87 {
  88   /*  unsigned char key[md5_hash_len];
  89   SilcMarsContext *ctx = (SilcMarsContext *)context;
  90
  91   make_md5_hash(string, &key);
  92   memcpy(&ctx->key, mars_set_key(&key, keylen), keylen);
  93   memset(&key, 'F', sizeoof(key));
  94   */
  95
  96   return 1;
  97 }
  98
  99 /* Returns the size of the cipher context. */
 100
 101 SILC_CIPHER_API_CONTEXT_LEN(cast)
 102 {
 103   return sizeof(CastContext);
 104 }
 105
 106 /* Encrypts with the cipher in CBC mode. Source and destination buffers
 107    maybe one and same. */
 108
 109 SILC_CIPHER_API_ENCRYPT_CBC(cast)
 110 {
 111   SilcUInt32 tiv[4];
 112   int i;
 113
 114   SILC_CBC_GET_IV(tiv, iv);
 115
 116   SILC_CBC_ENC_PRE(tiv, src);
 117   cast_encrypt((CastContext *)context, tiv, tiv);
 118   SILC_CBC_ENC_POST(tiv, dst, src);
 119
 120   for (i = 16; i < len; i += 16) {
 121     SILC_CBC_ENC_PRE(tiv, src);
 122     cast_encrypt((CastContext *)context, tiv, tiv);
 123     SILC_CBC_ENC_POST(tiv, dst, src);
 124   }
 125
 126   SILC_CBC_PUT_IV(tiv, iv);
 127
 128   return TRUE;
 129 }
 130
 131 /* Decrypts with the cipher in CBC mode. Source and destination buffers
 132    maybe one and same. */
 133
 134 SILC_CIPHER_API_DECRYPT_CBC(cast)
 135 {
 136   SilcUInt32 tmp[4], tmp2[4], tiv[4];
 137   int i;
 138
 139   SILC_CBC_GET_IV(tiv, iv);
 140
 141   SILC_CBC_DEC_PRE(tmp, src);
 142   cast_decrypt((CastContext *)context, tmp, tmp2);
 143   SILC_CBC_DEC_POST(tmp2, dst, src, tmp, tiv);
 144
 145   for (i = 16; i < len; i += 16) {
 146     SILC_CBC_DEC_PRE(tmp, src);
 147     cast_decrypt((CastContext *)context, tmp, tmp2);
 148     SILC_CBC_DEC_POST(tmp2, dst, src, tmp, tiv);
 149   }
 150
 151   SILC_CBC_PUT_IV(tiv, iv);
 152
 153   return TRUE;
 154 }
 155
 156 u4byte s_box[4][256] =
 157 { {
 158     0x30fb40d4, 0x9fa0ff0b, 0x6beccd2f, 0x3f258c7a, 0x1e213f2f, 0x9C004dd3,
 159     0x6003e540, 0xcf9fc949, 0xbfd4af27, 0x88bbbdb5, 0xe2034090, 0x98d09675,
 160     0x6e63a0e0, 0x15c361d2, 0xc2e7661d, 0x22d4ff8e, 0x28683b6f, 0xc07fd059,
 161     0xff2379c8, 0x775f50e2, 0x43c340d3, 0xdf2f8656, 0x887ca41a, 0xa2d2bd2d,
 162     0xa1c9e0d6, 0x346c4819, 0x61b76d87, 0x22540f2f, 0x2abe32e1, 0xaa54166b,
 163     0x22568e3a, 0xa2d341d0, 0x66db40c8, 0xa784392f, 0x004dff2f, 0x2db9d2de,
 164     0x97943fac, 0x4a97c1d8, 0x527644b7, 0xb5f437a7, 0xb82cbaef, 0xd751d159,
 165     0x6ff7f0ed, 0x5a097a1f, 0x827b68d0, 0x90ecf52e, 0x22b0c054, 0xbc8e5935,
 166     0x4b6d2f7f, 0x50bb64a2, 0xd2664910, 0xbee5812d, 0xb7332290, 0xe93b159f,
 167     0xb48ee411, 0x4bff345d, 0xfd45c240, 0xad31973f, 0xc4f6d02e, 0x55fc8165,
 168     0xd5b1caad, 0xa1ac2dae, 0xa2d4b76d, 0xc19b0C50, 0x882240f2, 0x0c6e4f38,
 169     0xa4e4bfd7, 0x4f5ba272, 0x564c1d2f, 0xc59c5319, 0xb949e354, 0xb04669fe,
 170     0xb1b6ab8a, 0xc71358dd, 0x6385c545, 0x110f935d, 0x57538ad5, 0x6a390493,
 171     0xe63d37e0, 0x2a54f6b3, 0x3a787d5f, 0x6276a0b5, 0x19a6fcdf, 0x7a42206a,
 172     0x29f9d4d5, 0xf61b1891, 0xbb72275e, 0xaa508167, 0x38901091, 0xc6b505eb,
 173     0x84c7cb8c, 0x2ad75a0f, 0x874a1427, 0xa2d1936b, 0x2ad286af, 0xaa56d291,
 174     0xd7894360, 0x425c750d, 0x93b39e26, 0x187184c9, 0x6c00b32d, 0x73e2bb14,
 175     0xa0bebc3c, 0x54623779, 0x64459eab, 0x3f328b82, 0x7718cf82, 0x59a2cea6,
 176     0x04ee002e, 0x89fe78e6, 0x3fab0950, 0x325ff6C2, 0x81383f05, 0x6963c5c8,
 177     0x76cb5ad6, 0xd49974c9, 0xca180dcf, 0x380782d5, 0xc7fa5cf6, 0x8ac31511,
 178     0x35e79e13, 0x47da91d0, 0xf40f9086, 0xa7e2419e, 0x31366241, 0x051ef495,
 179     0xaa573b04, 0x4a805d8d, 0x548300d0, 0x00322a3c, 0xbf64cddf, 0xba57a68e,
 180     0x75c6372b, 0x50afd341, 0xa7c13275, 0x915a0bf5, 0x6b54bfab, 0x2b0b1426,
 181     0xab4cc9d7, 0x449ccd82, 0xf7fbf265, 0xab85c5f3, 0x1b55db94, 0xaad4e324,
 182     0xcfa4bd3f, 0x2deaa3e2, 0x9e204d02, 0xc8bd25ac, 0xeadf55b3, 0xd5bd9e98,
 183     0xe31231b2, 0x2ad5ad6c, 0x954329de, 0xadbe4528, 0xd8710f69, 0xaa51c90f,
 184     0xaa786bf6, 0x22513f1e, 0xaa51a79b, 0x2ad344cc, 0x7b5a41f0, 0xd37cfbad,
 185     0x1b069505, 0x41ece491, 0xb4c332e6, 0x032268d4, 0xc9600acc, 0xce387e6d,
 186     0xbf6bb16c, 0x6a70fb78, 0x0d03d9c9, 0xd4df39de, 0xe01063da, 0x4736f464,
 187     0x5ad328d8, 0xb347cc96, 0x75bb0fc3, 0x98511bfb, 0x4ffbcc35, 0xb58bcf6a,
 188     0xe11f0abc, 0xbfc5fe4a, 0xa70aec10, 0xac39570a, 0x3f04442f, 0x6188b153,
 189     0xe0397a2e, 0x5727cb79, 0x9ceb418f, 0x1cacd68d, 0x2ad37c96, 0x0175cb9d,
 190     0xc69dff09, 0xc75b65f0, 0xd9db40d8, 0xec0e7779, 0x4744ead4, 0xb11c3274,
 191     0xdd24cb9e, 0x7e1c54bd, 0xf01144f9, 0xd2240eb1, 0x9675b3fd, 0xa3ac3755,
 192     0xd47c27af, 0x51c85f4d, 0x56907596, 0xa5bb15e6, 0x580304f0, 0xca042cf1,
 193     0x011a37ea, 0x8dbfaadb, 0x35ba3e4a, 0x3526ffa0, 0xc37b4d09, 0xbc306ed9,
 194     0x98a52666, 0x5648f725, 0xff5e569d, 0x0ced63d0, 0x7c63b2cf, 0x700b45e1,
 195     0xd5ea50f1, 0x85a92872, 0xaf1fbda7, 0xd4234870, 0xa7870bf3, 0x2d3b4d79,
 196     0x42e04198, 0x0cd0ede7, 0x26470db8, 0xf881814C, 0x474d6ad7, 0x7c0c5e5c,
 197     0xd1231959, 0x381b7298, 0xf5d2f4db, 0xab838653, 0x6e2f1e23, 0x83719c9e,
 198     0xbd91e046, 0x9a56456e, 0xdc39200c, 0x20c8c571, 0x962bda1c, 0xe1e696ff,
 199     0xb141ab08, 0x7cca89b9, 0x1a69e783, 0x02cc4843, 0xa2f7c579, 0x429ef47d,
 200     0x427b169c, 0x5ac9f049, 0xdd8f0f00, 0x5c8165bf
 201   },
 202   {
 203     0x1f201094, 0xef0ba75b, 0x69e3cf7e, 0x393f4380, 0xfe61cf7a, 0xeec5207a,
 204     0x55889c94, 0x72fc0651, 0xada7ef79, 0x4e1d7235, 0xd55a63ce, 0xde0436ba,
 205     0x99c430ef, 0x5f0c0794, 0x18dcdb7d, 0xa1d6eff3, 0xa0b52f7b, 0x59e83605,
 206     0xee15b094, 0xe9ffd909, 0xdc440086, 0xef944459, 0xba83ccb3, 0xe0c3cdfb,
 207     0xd1da4181, 0x3b092ab1, 0xf997f1c1, 0xa5e6cf7b, 0x01420ddb, 0xe4e7ef5b,
 208     0x25a1ff41, 0xe180f806, 0x1fc41080, 0x179bee7a, 0xd37ac6a9, 0xfe5830a4,
 209     0x98de8b7f, 0x77e83f4e, 0x79929269, 0x24fa9f7b, 0xe113c85b, 0xacc40083,
 210     0xd7503525, 0xf7ea615f, 0x62143154, 0x0d554b63, 0x5d681121, 0xc866c359,
 211     0x3d63cf73, 0xcee234c0, 0xd4d87e87, 0x5c672b21, 0x071f6181, 0x39f7627f,
 212     0x361e3084, 0xe4eb573b, 0x602f64a4, 0xd63acd9c, 0x1bbc4635, 0x9e81032d,
 213     0x2701f50c, 0x99847ab4, 0xa0e3df79, 0xba6cf38c, 0x10843094, 0x2537a95e,
 214     0xf46f6ffe, 0xa1ff3b1f, 0x208cfb6a, 0x8f458c74, 0xd9e0a227, 0x4ec73a34,
 215     0xfc884f69, 0x3e4de8df, 0xef0e0088, 0x3559648d, 0x8a45388c, 0x1d804366,
 216     0x721d9bfd, 0xa58684bb, 0xe8256333, 0x844e8212, 0x128d8098, 0xfed33fb4,
 217     0xce280ae1, 0x27e19ba5, 0xd5a6c252, 0xe49754bd, 0xc5d655dd, 0xeb667064,
 218     0x77840b4d, 0xa1b6a801, 0x84db26a9, 0xe0b56714, 0x21f043b7, 0xe5d05860,
 219     0x54f03084, 0x066ff472, 0xa31aa153, 0xdadc4755, 0xb5625dbf, 0x68561be6,
 220     0x83ca6b94, 0x2d6ed23b, 0xeccf01db, 0xa6d3d0ba, 0xb6803d5c, 0xaf77a709,
 221     0x33b4a34c, 0x397bc8d6, 0x5ee22b95, 0x5f0e5304, 0x81ed6f61, 0x20e74364,
 222     0xb45e1378, 0xde18639b, 0x881ca122, 0xb96726d1, 0x8049a7e8, 0x22b7da7b,
 223     0x5e552d25, 0x5272d237, 0x79d2951c, 0xc60d894c, 0x488cb402, 0x1ba4fe5b,
 224     0xa4b09f6b, 0x1ca815cf, 0xa20c3005, 0x8871df63, 0xb9de2fcb, 0x0cc6c9e9,
 225     0x0beeff53, 0xe3214517, 0xb4542835, 0x9f63293c, 0xee41e729, 0x6e1d2d7c,
 226     0x50045286, 0x1e6685f3, 0xf33401c6, 0x30a22c95, 0x31a70850, 0x60930f13,
 227     0x73f98417, 0xa1269859, 0xec645c44, 0x52c877a9, 0xcdff33a6, 0xa02b1741,
 228     0x7cbad9a2, 0x2180036f, 0x50d99c08, 0xcb3f4861, 0xc26bd765, 0x64a3f6ab,
 229     0x80342676, 0x25a75e7b, 0xe4e6d1fc, 0x20c710e6, 0xcdf0b680, 0x17844d3b,
 230     0x31eef84d, 0x7e0824e4, 0x2ccb49eb, 0x846a3bae, 0x8ff77888, 0xee5d60f6,
 231     0x7af75673, 0x2fdd5cdb, 0xa11631c1, 0x30f66f43, 0xb3faec54, 0x157fd7fa,
 232     0xef8579cc, 0xd152de58, 0xdb2ffd5e, 0x8f32ce19, 0x306af97a, 0x02f03ef8,
 233     0x99319ad5, 0xc242fa0f, 0xa7e3ebb0, 0xc68e4906, 0xb8da230c, 0x80823028,
 234     0xdcdef3c8, 0xd35fb171, 0x088a1bc8, 0xbec0c560, 0x61a3c9e8, 0xbca8f54d,
 235     0xc72feffa, 0x22822e99, 0x82c570b4, 0xd8d94e89, 0x8b1c34bc, 0x301e16e6,
 236     0x273be979, 0xb0ffeaa6, 0x61d9b8c6, 0x00b24869, 0xb7ffce3f, 0x08dc283b,
 237     0x43daf65a, 0xf7e19798, 0x7619b72f, 0x8f1c9ba4, 0xdc8637a0, 0x16a7d3b1,
 238     0x9fc393b7, 0xa7136eeb, 0xc6bcc63e, 0x1a513742, 0xef6828bc, 0x520365d6,
 239     0x2d6a77ab, 0x3527ed4b, 0x821fd216, 0x095c6e2e, 0xdb92f2fb, 0x5eea29cb,
 240     0x145892f5, 0x91584f7f, 0x5483697b, 0x2667a8cc, 0x85196048, 0x8c4bacea,
 241     0x833860d4, 0x0d23e0f9, 0x6c387e8a, 0x0ae6d249, 0xb284600c, 0xd835731d,
 242     0xdcb1c647, 0xac4c56ea, 0x3ebd81b3, 0x230eabb0, 0x6438bc87, 0xf0b5b1fa,
 243     0x8f5ea2b3, 0xfc184642, 0x0a036b7a, 0x4fb089bd, 0x649da589, 0xa345415e,
 244     0x5c038323, 0x3e5d3bb9, 0x43d79572, 0x7e6dd07c, 0x06dfdf1e, 0x6c6cc4ef,
 245     0x7160a539, 0x73bfbe70, 0x83877605, 0x4523ecf1
 246   },
 247   {
 248     0x8defc240, 0x25fa5d9f, 0xeb903dbf, 0xe810c907, 0x47607fff, 0x369fe44b,
 249     0x8c1fc644, 0xaececa90, 0xbeb1f9bf, 0xeefbcaea, 0xe8cf1950, 0x51df07ae,
 250     0x920e8806, 0xf0ad0548, 0xe13c8d83, 0x927010d5, 0x11107d9f, 0x07647db9,
 251     0xb2e3e4d4, 0x3d4f285e, 0xb9afa820, 0xfade82e0, 0xa067268b, 0x8272792e,
 252     0x553fb2c0, 0x489ae22b, 0xd4ef9794, 0x125e3fbc, 0x21fffcee, 0x825b1bfd,
 253     0x9255c5ed, 0x1257a240, 0x4e1a8302, 0xbae07fff, 0x528246e7, 0x8e57140e,
 254     0x3373f7bf, 0x8c9f8188, 0xa6fc4ee8, 0xc982b5a5, 0xa8c01db7, 0x579fc264,
 255     0x67094f31, 0xf2bd3f5f, 0x40fff7c1, 0x1fb78dfc, 0x8e6bd2c1, 0x437be59b,
 256     0x99b03dbf, 0xb5dbc64b, 0x638dc0e6, 0x55819d99, 0xa197c81c, 0x4a012d6e,
 257     0xc5884a28, 0xccc36f71, 0xb843c213, 0x6c0743f1, 0x8309893c, 0x0feddd5f,
 258     0x2f7fe850, 0xd7c07f7e, 0x02507fbf, 0x5afb9a04, 0xa747d2d0, 0x1651192e,
 259     0xaf70bf3e, 0x58c31380, 0x5f98302e, 0x727cc3c4, 0x0a0fb402, 0x0f7fef82,
 260     0x8c96fdad, 0x5d2c2aae, 0x8ee99a49, 0x50da88b8, 0x8427f4a0, 0x1eac5790,
 261     0x796fb449, 0x8252dc15, 0xefbd7d9b, 0xa672597d, 0xada840d8, 0x45f54504,
 262     0xfa5d7403, 0xe83ec305, 0x4f91751a, 0x925669c2, 0x23efe941, 0xa903f12e,
 263     0x60270df2, 0x0276e4b6, 0x94fd6574, 0x927985b2, 0x8276dbcb, 0x02778176,
 264     0xf8af918d, 0x4e48f79e, 0x8f616ddf, 0xe29d840e, 0x842f7d83, 0x340ce5c8,
 265     0x96bbb682, 0x93b4b148, 0xef303cab, 0x984faf28, 0x779faf9b, 0x92dc560d,
 266     0x224d1e20, 0x8437aa88, 0x7d29dc96, 0x2756d3dc, 0x8b907cee, 0xb51fd240,
 267     0xe7c07ce3, 0xe566b4a1, 0xc3e9615e, 0x3cf8209d, 0x6094d1e3, 0xcd9ca341,
 268     0x5c76460e, 0x00ea983b, 0xd4d67881, 0xfd47572c, 0xf76cedd9, 0xbda8229c,
 269     0x127dadaa, 0x438a074e, 0x1f97c090, 0x081bdb8a, 0x93a07ebe, 0xb938ca15,
 270     0x97b03cff, 0x3dc2c0f8, 0x8d1ab2ec, 0x64380e51, 0x68cc7bfb, 0xd90f2788,
 271     0x12490181, 0x5de5ffd4, 0xdd7ef86a, 0x76a2e214, 0xb9a40368, 0x925d958f,
 272     0x4b39fffa, 0xba39aee9, 0xa4ffd30b, 0xfaf7933b, 0x6d498623, 0x193cbcfa,
 273     0x27627545, 0x825cf47a, 0x61bd8ba0, 0xd11e42d1, 0xcead04f4, 0x127ea392,
 274     0x10428db7, 0x8272a972, 0x9270c4a8, 0x127de50b, 0x285ba1c8, 0x3c62f44f,
 275     0x35c0eaa5, 0xe805d231, 0x428929fb, 0xb4fcdf82, 0x4fb66a53, 0x0e7dc15b,
 276     0x1f081fab, 0x108618ae, 0xfcfd086d, 0xf9ff2889, 0x694bcc11, 0x236a5cae,
 277     0x12deca4d, 0x2c3f8cc5, 0xd2d02dfe, 0xf8ef5896, 0xe4cf52da, 0x95155b67,
 278     0x494a488c, 0xb9b6a80c, 0x5c8f82bc, 0x89d36b45, 0x3a609437, 0xec00c9a9,
 279     0x44715253, 0x0a874b49, 0xd773bc40, 0x7c34671c, 0x02717ef6, 0x4feb5536,
 280     0xa2d02fff, 0xd2bf60c4, 0xd43f03c0, 0x50b4ef6d, 0x07478cd1, 0x006e1888,
 281     0xa2e53f55, 0xb9e6d4bc, 0xa2048016, 0x97573833, 0xd7207d67, 0xde0f8f3d,
 282     0x72f87b33, 0xabcc4f33, 0x7688c55d, 0x7b00a6b0, 0x947b0001, 0x570075d2,
 283     0xf9bb88f8, 0x8942019e, 0x4264a5ff, 0x856302e0, 0x72dbd92b, 0xee971b69,
 284     0x6ea22fde, 0x5f08ae2b, 0xaf7a616d, 0xe5c98767, 0xcf1febd2, 0x61efc8c2,
 285     0xf1ac2571, 0xcc8239c2, 0x67214cb8, 0xb1e583d1, 0xb7dc3e62, 0x7f10bdce,
 286     0xf90a5c38, 0x0ff0443d, 0x606e6dc6, 0x60543a49, 0x5727c148, 0x2be98a1d,
 287     0x8ab41738, 0x20e1be24, 0xaf96da0f, 0x68458425, 0x99833be5, 0x600d457d,
 288     0x282f9350, 0x8334b362, 0xd91d1120, 0x2b6d8da0, 0x642b1e31, 0x9c305a00,
 289     0x52bce688, 0x1b03588a, 0xf7baefd5, 0x4142ed9c, 0xa4315c11, 0x83323ec5,
 290     0xdfef4636, 0xa133c501, 0xe9d3531c, 0xee353783
 291   },
 292   {
 293     0x9db30420, 0x1fb6e9de, 0xa7be7bef, 0xd273a298, 0x4a4f7bdb, 0x64ad8c57,
 294     0x85510443, 0xfa020ed1, 0x7e287aff, 0xe60fb663, 0x095f35a1, 0x79ebf120,
 295     0xfd059d43, 0x6497b7b1, 0xf3641f63, 0x241e4adf, 0x28147f5f, 0x4fa2b8cd,
 296     0xc9430040, 0x0cc32220, 0xfdd30b30, 0xc0a5374f, 0x1d2d00d9, 0x24147b15,
 297     0xee4d111a, 0x0fca5167, 0x71ff904c, 0x2d195ffe, 0x1a05645f, 0x0c13fefe,
 298     0x081b08ca, 0x05170121, 0x80530100, 0xe83e5efe, 0xac9af4f8, 0x7fe72701,
 299     0xd2b8ee5f, 0x06df4261, 0xbb9e9b8a, 0x7293ea25, 0xce84ffdf, 0xf5718801,
 300     0x3dd64b04, 0xa26f263b, 0x7ed48400, 0x547eebe6, 0x446d4ca0, 0x6cf3d6f5,
 301     0x2649abdf, 0xaea0c7f5, 0x36338cc1, 0x503f7e93, 0xd3772061, 0x11b638e1,
 302     0x72500e03, 0xf80eb2bb, 0xabe0502e, 0xec8d77de, 0x57971e81, 0xe14f6746,
 303     0xc9335400, 0x6920318f, 0x081dbb99, 0xffc304a5, 0x4d351805, 0x7f3d5ce3,
 304     0xa6c866c6, 0x5d5bcca9, 0xdaec6fea, 0x9f926f91, 0x9f46222f, 0x3991467d,
 305     0xa5bf6d8e, 0x1143c44f, 0x43958302, 0xd0214eeb, 0x022083b8, 0x3fb6180c,
 306     0x18f8931e, 0x281658e6, 0x26486e3e, 0x8bd78a70, 0x7477e4c1, 0xb506e07c,
 307     0xf32d0a25, 0x79098b02, 0xe4eabb81, 0x28123b23, 0x69dead38, 0x1574ca16,
 308     0xdf871b62, 0x211c40b7, 0xa51a9ef9, 0x0014377b, 0x041e8ac8, 0x09114003,
 309     0xbd59e4d2, 0xe3d156d5, 0x4fe876d5, 0x2f91a340, 0x557be8de, 0x00eae4a7,
 310     0x0ce5c2ec, 0x4db4bba6, 0xe756bdff, 0xdd3369ac, 0xec17b035, 0x06572327,
 311     0x99afc8b0, 0x56c8c391, 0x6b65811c, 0x5e146119, 0x6e85cb75, 0xbe07c002,
 312     0xc2325577, 0x893ff4ec, 0x5bbfc92d, 0xd0ec3b25, 0xb7801ab7, 0x8d6d3b24,
 313     0x20c763ef, 0xc366a5fc, 0x9c382880, 0x0ace3205, 0xaac9548a, 0xeca1d7c7,
 314     0x041afa32, 0x1d16625a, 0x6701902c, 0x9b757a54, 0x31d477f7, 0x9126b031,
 315     0x36cc6fdb, 0xc70b8b46, 0xd9e66a48, 0x56e55a79, 0x026a4ceb, 0x52437eff,
 316     0x2f8f76b4, 0x0df980a5, 0x8674cde3, 0xedda04eb, 0x17a9be04, 0x2c18f4df,
 317     0xb7747f9d, 0xab2af7b4, 0xefc34d20, 0x2e096b7c, 0x1741a254, 0xe5b6a035,
 318     0x213d42f6, 0x2c1c7c26, 0x61c2f50f, 0x6552daf9, 0xd2c231f8, 0x25130f69,
 319     0xd8167fa2, 0x0418f2c8, 0x001a96a6, 0x0d1526ab, 0x63315c21, 0x5e0a72ec,
 320     0x49bafefd, 0x187908d9, 0x8d0dbd86, 0x311170a7, 0x3e9b640c, 0xcc3e10d7,
 321     0xd5cad3b6, 0x0caec388, 0xf73001e1, 0x6c728aff, 0x71eae2a1, 0x1f9af36e,
 322     0xcfcbd12f, 0xc1de8417, 0xac07be6b, 0xcb44a1d8, 0x8b9b0f56, 0x013988c3,
 323     0xb1c52fca, 0xb4be31cd, 0xd8782806, 0x12a3a4e2, 0x6f7de532, 0x58fd7eb6,
 324     0xd01ee900, 0x24adffc2, 0xf4990fc5, 0x9711aac5, 0x001d7b95, 0x82e5e7d2,
 325     0x109873f6, 0x00613096, 0xc32d9521, 0xada121ff, 0x29908415, 0x7fbb977f,
 326     0xaf9eb3db, 0x29c9ed2a, 0x5ce2a465, 0xa730f32c, 0xd0aa3fe8, 0x8a5cc091,
 327     0xd49e2ce7, 0x0ce454a9, 0xd60acd86, 0x015f1919, 0x77079103, 0xdea03af6,
 328     0x78a8565e, 0xdee356df, 0x21f05cbe, 0x8b75e387, 0xb3c50651, 0xb8a5c3ef,
 329     0xd8eeb6d2, 0xe523be77, 0xc2154529, 0x2f69efdf, 0xafe67afb, 0xf470c4b2,
 330     0xf3e0eb5b, 0xd6cc9876, 0x39e4460c, 0x1fda8538, 0x1987832f, 0xca007367,
 331     0xa99144f8, 0x296b299e, 0x492fc295, 0x9266beab, 0xb5676e69, 0x9bd3ddda,
 332     0xdf7e052f, 0xdb25701c, 0x1b5e51ee, 0xf65324e6, 0x6afce36c, 0x0316cc04,
 333     0x8644213e, 0xb7dc59d0, 0x7965291f, 0xccd6fd43, 0x41823979, 0x932bcdf6,
 334     0xb657c34d, 0x4edfd282, 0x7ae5290c, 0x3cb9536b, 0x851e20fe, 0x9833557e,
 335     0x13ecf0b0, 0xd3ffb372, 0x3f85c5c1, 0x0aef7ed2
 336   }
 337 };
 338
 339 #define f1(y,x,kr,km)                           \
 340     t  = rotl(km + x, kr);                      \
 341     u  = s_box[0][byte(t,3)];                   \
 342     u ^= s_box[1][byte(t,2)];                   \
 343     u -= s_box[2][byte(t,1)];                   \
 344     u += s_box[3][byte(t,0)];                   \
 345     y ^= u;
 346
 347 #define f2(y,x,kr,km)                           \
 348     t  = rotl(km ^ x, kr);                      \
 349     u  = s_box[0][byte(t,3)];                   \
 350     u -= s_box[1][byte(t,2)];                   \
 351     u += s_box[2][byte(t,1)];                   \
 352     u ^= s_box[3][byte(t,0)];                   \
 353     y ^= u;
 354
 355 #define f3(y,x,kr,km)                           \
 356     t  = rotl(km - x, kr);                      \
 357     u  = s_box[0][byte(t,3)];                   \
 358     u += s_box[1][byte(t,2)];                   \
 359     u ^= s_box[2][byte(t,1)];                   \
 360     u -= s_box[3][byte(t,0)];                   \
 361     y ^= u;
 362
 363 #define f_rnd(x,n)                              \
 364     f1(x[2],x[3],l_key[n],    l_key[n + 4]);    \
 365     f2(x[1],x[2],l_key[n + 1],l_key[n + 5]);    \
 366     f3(x[0],x[1],l_key[n + 2],l_key[n + 6]);    \
 367     f1(x[3],x[0],l_key[n + 3],l_key[n + 7]);
 368
 369 #define i_rnd(x, n)                             \
 370     f1(x[3],x[0],l_key[n + 3],l_key[n + 7]);    \
 371     f3(x[0],x[1],l_key[n + 2],l_key[n + 6]);    \
 372     f2(x[1],x[2],l_key[n + 1],l_key[n + 5]);    \
 373     f1(x[2],x[3],l_key[n],    l_key[n + 4]);
 374
 375 #define k_rnd(k,tr,tm)                          \
 376     f1(k[6],k[7],tr[0],tm[0]);                  \
 377     f2(k[5],k[6],tr[1],tm[1]);                  \
 378     f3(k[4],k[5],tr[2],tm[2]);                  \
 379     f1(k[3],k[4],tr[3],tm[3]);                  \
 380     f2(k[2],k[3],tr[4],tm[4]);                  \
 381     f3(k[1],k[2],tr[5],tm[5]);                  \
 382     f1(k[0],k[1],tr[6],tm[6]);                  \
 383     f2(k[7],k[0],tr[7],tm[7]);
 384
 385 /* initialise the key schedule from the user supplied key   */
 386
 387 u4byte *cast_set_key(CastContext *ctx,
 388                      const u4byte in_key[], const u4byte key_len)
 389 {
 390     u4byte  i, j, t, u, cm, cr, lk[8], tm[8], tr[8];
 391     u4byte *l_key = ctx->l_key;
 392
 393     for(i = 0; i < key_len / 32; ++i)
 394
 395         lk[i] = io_swap(in_key[i]);
 396
 397     for(; i < 8; ++i)
 398
 399         lk[i] = 0;
 400
 401     cm = 0x5a827999; cr = 19;
 402
 403     for(i = 0; i < 96; i += 8)
 404     {
 405         for(j = 0; j < 8; ++j)
 406         {
 407             tm[j] = cm; cm += 0x6ed9eba1;
 408             tr[j] = cr; cr += 17;
 409         }
 410
 411         k_rnd(lk, tr, tm);
 412
 413         for(j = 0; j < 8; ++j)
 414         {
 415             tm[j] = cm; cm += 0x6ed9eba1;
 416             tr[j] = cr; cr += 17;
 417         }
 418
 419         k_rnd(lk, tr, tm);
 420
 421         l_key[i + 0] = lk[0]; l_key[i + 1] = lk[2];
 422         l_key[i + 2] = lk[4]; l_key[i + 3] = lk[6];
 423         l_key[i + 4] = lk[7]; l_key[i + 5] = lk[5];
 424         l_key[i + 6] = lk[3]; l_key[i + 7] = lk[1];
 425     }
 426
 427     return l_key;
 428 }
 429
 430 /* encrypt a block of text  */
 431
 432 void cast_encrypt(CastContext *ctx,
 433                   const u4byte in_blk[4], u4byte out_blk[])
 434 {
 435     u4byte  t, u, blk[4];
 436     u4byte *l_key = ctx->l_key;
 437
 438     blk[0] = io_swap(in_blk[0]); blk[1] = io_swap(in_blk[1]);
 439     blk[2] = io_swap(in_blk[2]); blk[3] = io_swap(in_blk[3]);
 440
 441     f_rnd(blk,  0); f_rnd(blk,  8);
 442     f_rnd(blk, 16); f_rnd(blk, 24);
 443     f_rnd(blk, 32); f_rnd(blk, 40);
 444     i_rnd(blk, 48); i_rnd(blk, 56);
 445     i_rnd(blk, 64); i_rnd(blk, 72);
 446     i_rnd(blk, 80); i_rnd(blk, 88);
 447
 448     out_blk[0] = io_swap(blk[0]); out_blk[1] = io_swap(blk[1]);
 449     out_blk[2] = io_swap(blk[2]); out_blk[3] = io_swap(blk[3]);
 450 }
 451
 452 /* decrypt a block of text  */
 453
 454 void cast_decrypt(CastContext *ctx,
 455                   const u4byte in_blk[4], u4byte out_blk[4])
 456 {
 457     u4byte  t, u, blk[4];
 458     u4byte *l_key = ctx->l_key;
 459
 460     blk[0] = io_swap(in_blk[0]); blk[1] = io_swap(in_blk[1]);
 461     blk[2] = io_swap(in_blk[2]); blk[3] = io_swap(in_blk[3]);
 462
 463     f_rnd(blk, 88); f_rnd(blk, 80);
 464     f_rnd(blk, 72); f_rnd(blk, 64);
 465     f_rnd(blk, 56); f_rnd(blk, 48);
 466     i_rnd(blk, 40); i_rnd(blk, 32);
 467     i_rnd(blk, 24); i_rnd(blk, 16);
 468     i_rnd(blk,  8); i_rnd(blk,  0);
 469
 470     out_blk[0] = io_swap(blk[0]); out_blk[1] = io_swap(blk[1]);
 471     out_blk[2] = io_swap(blk[2]); out_blk[3] = io_swap(blk[3]);
 472 }