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