apg-2.*: cast/cast.c

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Member "apg-2.2.3/cast/cast.c" (7 Aug 2003, 6832 Bytes) of package /linux/privat/old/apg-2.2.3.tar.gz:

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1 /* 2 * CAST-128 in C 3 * Written by Steve Reid <sreid@sea-to-sky.net> 4 * 100% Public Domain - no warranty 5 * Released 1997.10.11 6 */ 7 8 #include "cast.h" 9 #include "cast_sboxes.h" 10 11 /* Macros to access 8-bit bytes out of a 32-bit word */ 12 #define U8a(x) ( (u8) (x>>24) ) 13 #define U8b(x) ( (u8) ((x>>16)&255) ) 14 #define U8c(x) ( (u8) ((x>>8)&255) ) 15 #define U8d(x) ( (u8) ((x)&255) ) 16 17 /* Circular left shift */ 18 #define ROL(x, n) ( ((x)<<(n)) | ((x)>>(32-(n))) ) 19 20 /* CAST-128 uses three different round functions */ 21 #define F1(l, r, i) \ 22 t = ROL(key->xkey[i] + r, key->xkey[i+16]); \ 23 l ^= ((cast_sbox1[U8a(t)] ^ cast_sbox2[U8b(t)]) - \ 24 cast_sbox3[U8c(t)]) + cast_sbox4[U8d(t)]; 25 #define F2(l, r, i) \ 26 t = ROL(key->xkey[i] ^ r, key->xkey[i+16]); \ 27 l ^= ((cast_sbox1[U8a(t)] - cast_sbox2[U8b(t)]) + \ 28 cast_sbox3[U8c(t)]) ^ cast_sbox4[U8d(t)]; 29 #define F3(l, r, i) \ 30 t = ROL(key->xkey[i] - r, key->xkey[i+16]); \ 31 l ^= ((cast_sbox1[U8a(t)] + cast_sbox2[U8b(t)]) ^ \ 32 cast_sbox3[U8c(t)]) - cast_sbox4[U8d(t)]; 33 34 35 /***** Encryption Function *****/ 36 37 void cast_encrypt(cast_key* key, u8* inblock, u8* outblock) 38 { 39 u32 t, l, r; 40 41 /* Get inblock into l,r */ 42 l = ((u32)inblock[0] << 24) | ((u32)inblock[1] << 16) | 43 ((u32)inblock[2] << 8) | (u32)inblock[3]; 44 r = ((u32)inblock[4] << 24) | ((u32)inblock[5] << 16) | 45 ((u32)inblock[6] << 8) | (u32)inblock[7]; 46 /* Do the work */ 47 F1(l, r, 0); 48 F2(r, l, 1); 49 F3(l, r, 2); 50 F1(r, l, 3); 51 F2(l, r, 4); 52 F3(r, l, 5); 53 F1(l, r, 6); 54 F2(r, l, 7); 55 F3(l, r, 8); 56 F1(r, l, 9); 57 F2(l, r, 10); 58 F3(r, l, 11); 59 /* Only do full 16 rounds if key length > 80 bits */ 60 if (key->rounds > 12) { 61 F1(l, r, 12); 62 F2(r, l, 13); 63 F3(l, r, 14); 64 F1(r, l, 15); 65 } 66 /* Put l,r into outblock */ 67 outblock[0] = U8a(r); 68 outblock[1] = U8b(r); 69 outblock[2] = U8c(r); 70 outblock[3] = U8d(r); 71 outblock[4] = U8a(l); 72 outblock[5] = U8b(l); 73 outblock[6] = U8c(l); 74 outblock[7] = U8d(l); 75 /* Wipe clean */ 76 t = l = r = 0; 77 } 78 79 80 /***** Decryption Function *****/ 81 82 void cast_decrypt(cast_key* key, u8* inblock, u8* outblock) 83 { 84 u32 t, l, r; 85 86 /* Get inblock into l,r */ 87 r = ((u32)inblock[0] << 24) | ((u32)inblock[1] << 16) | 88 ((u32)inblock[2] << 8) | (u32)inblock[3]; 89 l = ((u32)inblock[4] << 24) | ((u32)inblock[5] << 16) | 90 ((u32)inblock[6] << 8) | (u32)inblock[7]; 91 /* Do the work */ 92 /* Only do full 16 rounds if key length > 80 bits */ 93 if (key->rounds > 12) { 94 F1(r, l, 15); 95 F3(l, r, 14); 96 F2(r, l, 13); 97 F1(l, r, 12); 98 } 99 F3(r, l, 11); 100 F2(l, r, 10); 101 F1(r, l, 9); 102 F3(l, r, 8); 103 F2(r, l, 7); 104 F1(l, r, 6); 105 F3(r, l, 5); 106 F2(l, r, 4); 107 F1(r, l, 3); 108 F3(l, r, 2); 109 F2(r, l, 1); 110 F1(l, r, 0); 111 /* Put l,r into outblock */ 112 outblock[0] = U8a(l); 113 outblock[1] = U8b(l); 114 outblock[2] = U8c(l); 115 outblock[3] = U8d(l); 116 outblock[4] = U8a(r); 117 outblock[5] = U8b(r); 118 outblock[6] = U8c(r); 119 outblock[7] = U8d(r); 120 /* Wipe clean */ 121 t = l = r = 0; 122 } 123 124 125 /***** Key Schedual *****/ 126 127 void cast_setkey(cast_key* key, u8* rawkey, int keybytes) 128 { 129 u32 t[4], z[4], x[4]; 130 int i; 131 132 /* Set number of rounds to 12 or 16, depending on key length */ 133 key->rounds = (keybytes <= 10 ? 12 : 16); 134 135 /* Copy key to workspace x */ 136 for (i = 0; i < 4; i++) { 137 x[i] = 0; 138 if ((i*4+0) < keybytes) x[i] = (u32)rawkey[i*4+0] << 24; 139 if ((i*4+1) < keybytes) x[i] |= (u32)rawkey[i*4+1] << 16; 140 if ((i*4+2) < keybytes) x[i] |= (u32)rawkey[i*4+2] << 8; 141 if ((i*4+3) < keybytes) x[i] |= (u32)rawkey[i*4+3]; 142 } 143 /* Generate 32 subkeys, four at a time */ 144 for (i = 0; i < 32; i+=4) { 145 switch (i & 4) { 146 case 0: 147 t[0] = z[0] = x[0] ^ cast_sbox5[U8b(x[3])] ^ 148 cast_sbox6[U8d(x[3])] ^ cast_sbox7[U8a(x[3])] ^ 149 cast_sbox8[U8c(x[3])] ^ cast_sbox7[U8a(x[2])]; 150 t[1] = z[1] = x[2] ^ cast_sbox5[U8a(z[0])] ^ 151 cast_sbox6[U8c(z[0])] ^ cast_sbox7[U8b(z[0])] ^ 152 cast_sbox8[U8d(z[0])] ^ cast_sbox8[U8c(x[2])]; 153 t[2] = z[2] = x[3] ^ cast_sbox5[U8d(z[1])] ^ 154 cast_sbox6[U8c(z[1])] ^ cast_sbox7[U8b(z[1])] ^ 155 cast_sbox8[U8a(z[1])] ^ cast_sbox5[U8b(x[2])]; 156 t[3] = z[3] = x[1] ^ cast_sbox5[U8c(z[2])] ^ 157 cast_sbox6[U8b(z[2])] ^ cast_sbox7[U8d(z[2])] ^ 158 cast_sbox8[U8a(z[2])] ^ cast_sbox6[U8d(x[2])]; 159 break; 160 case 4: 161 t[0] = x[0] = z[2] ^ cast_sbox5[U8b(z[1])] ^ 162 cast_sbox6[U8d(z[1])] ^ cast_sbox7[U8a(z[1])] ^ 163 cast_sbox8[U8c(z[1])] ^ cast_sbox7[U8a(z[0])]; 164 t[1] = x[1] = z[0] ^ cast_sbox5[U8a(x[0])] ^ 165 cast_sbox6[U8c(x[0])] ^ cast_sbox7[U8b(x[0])] ^ 166 cast_sbox8[U8d(x[0])] ^ cast_sbox8[U8c(z[0])]; 167 t[2] = x[2] = z[1] ^ cast_sbox5[U8d(x[1])] ^ 168 cast_sbox6[U8c(x[1])] ^ cast_sbox7[U8b(x[1])] ^ 169 cast_sbox8[U8a(x[1])] ^ cast_sbox5[U8b(z[0])]; 170 t[3] = x[3] = z[3] ^ cast_sbox5[U8c(x[2])] ^ 171 cast_sbox6[U8b(x[2])] ^ cast_sbox7[U8d(x[2])] ^ 172 cast_sbox8[U8a(x[2])] ^ cast_sbox6[U8d(z[0])]; 173 break; 174 } 175 switch (i & 12) { 176 case 0: 177 case 12: 178 key->xkey[i+0] = cast_sbox5[U8a(t[2])] ^ cast_sbox6[U8b(t[2])] ^ 179 cast_sbox7[U8d(t[1])] ^ cast_sbox8[U8c(t[1])]; 180 key->xkey[i+1] = cast_sbox5[U8c(t[2])] ^ cast_sbox6[U8d(t[2])] ^ 181 cast_sbox7[U8b(t[1])] ^ cast_sbox8[U8a(t[1])]; 182 key->xkey[i+2] = cast_sbox5[U8a(t[3])] ^ cast_sbox6[U8b(t[3])] ^ 183 cast_sbox7[U8d(t[0])] ^ cast_sbox8[U8c(t[0])]; 184 key->xkey[i+3] = cast_sbox5[U8c(t[3])] ^ cast_sbox6[U8d(t[3])] ^ 185 cast_sbox7[U8b(t[0])] ^ cast_sbox8[U8a(t[0])]; 186 break; 187 case 4: 188 case 8: 189 key->xkey[i+0] = cast_sbox5[U8d(t[0])] ^ cast_sbox6[U8c(t[0])] ^ 190 cast_sbox7[U8a(t[3])] ^ cast_sbox8[U8b(t[3])]; 191 key->xkey[i+1] = cast_sbox5[U8b(t[0])] ^ cast_sbox6[U8a(t[0])] ^ 192 cast_sbox7[U8c(t[3])] ^ cast_sbox8[U8d(t[3])]; 193 key->xkey[i+2] = cast_sbox5[U8d(t[1])] ^ cast_sbox6[U8c(t[1])] ^ 194 cast_sbox7[U8a(t[2])] ^ cast_sbox8[U8b(t[2])]; 195 key->xkey[i+3] = cast_sbox5[U8b(t[1])] ^ cast_sbox6[U8a(t[1])] ^ 196 cast_sbox7[U8c(t[2])] ^ cast_sbox8[U8d(t[2])]; 197 break; 198 } 199 switch (i & 12) { 200 case 0: 201 key->xkey[i+0] ^= cast_sbox5[U8c(z[0])]; 202 key->xkey[i+1] ^= cast_sbox6[U8c(z[1])]; 203 key->xkey[i+2] ^= cast_sbox7[U8b(z[2])]; 204 key->xkey[i+3] ^= cast_sbox8[U8a(z[3])]; 205 break; 206 case 4: 207 key->xkey[i+0] ^= cast_sbox5[U8a(x[2])]; 208 key->xkey[i+1] ^= cast_sbox6[U8b(x[3])]; 209 key->xkey[i+2] ^= cast_sbox7[U8d(x[0])]; 210 key->xkey[i+3] ^= cast_sbox8[U8d(x[1])]; 211 break; 212 case 8: 213 key->xkey[i+0] ^= cast_sbox5[U8b(z[2])]; 214 key->xkey[i+1] ^= cast_sbox6[U8a(z[3])]; 215 key->xkey[i+2] ^= cast_sbox7[U8c(z[0])]; 216 key->xkey[i+3] ^= cast_sbox8[U8c(z[1])]; 217 break; 218 case 12: 219 key->xkey[i+0] ^= cast_sbox5[U8d(x[0])]; 220 key->xkey[i+1] ^= cast_sbox6[U8d(x[1])]; 221 key->xkey[i+2] ^= cast_sbox7[U8a(x[2])]; 222 key->xkey[i+3] ^= cast_sbox8[U8b(x[3])]; 223 break; 224 } 225 if (i >= 16) { 226 key->xkey[i+0] &= 31; 227 key->xkey[i+1] &= 31; 228 key->xkey[i+2] &= 31; 229 key->xkey[i+3] &= 31; 230 } 231 } 232 /* Wipe clean */ 233 for (i = 0; i < 4; i++) { 234 t[i] = x[i] = z[i] = 0; 235 } 236 } 237 238 /* Made in Canada */ 239