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