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