comparison: gcrypt/idea.c
gcrypt/idea.c
- changeset 602
- 6b1bca241155
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| -1:000000000000 | 0:bcf51b2a9041 |
|---|---|
| 1 #include <config.h> | |
| 2 #include <stdio.h> | |
| 3 #include <stdlib.h> | |
| 4 #include <string.h> /* for memcmp() */ | |
| 5 #include <assert.h> | |
| 6 | |
| 7 #include "types.h" /* for byte and u32 typedefs */ | |
| 8 #include "g10lib.h" | |
| 9 #include "cipher.h" | |
| 10 | |
| 11 /* configuration stuff */ | |
| 12 #ifdef __alpha__ | |
| 13 #define SIZEOF_UNSIGNED_LONG 8 | |
| 14 #else | |
| 15 #define SIZEOF_UNSIGNED_LONG 4 | |
| 16 #endif | |
| 17 | |
| 18 #if defined(__mc68000__) || defined (__sparc__) || defined (__PPC__) \ | |
| 19 || (defined(__mips__) && (defined(MIPSEB) || defined (__MIPSEB__)) ) \ | |
| 20 || defined(__powerpc__) \ | |
| 21 || defined(__hpux__) /* should be replaced by the Macro for the PA */ | |
| 22 #define BIG_ENDIAN_HOST 1 | |
| 23 #else | |
| 24 #define LITTLE_ENDIAN_HOST 1 | |
| 25 #endif | |
| 26 | |
| 27 #ifndef DIM | |
| 28 #define DIM(v) (sizeof(v)/sizeof((v)[0])) | |
| 29 #define DIMof(type,member) DIM(((type *)0)->member) | |
| 30 #endif | |
| 31 | |
| 32 /* imports */ | |
| 33 void g10_log_fatal( const char *fmt, ... ); | |
| 34 | |
| 35 | |
| 36 /* local stuff */ | |
| 37 | |
| 38 #define FNCCAST_SETKEY(f) ((int(*)(void*, byte*, unsigned))(f)) | |
| 39 #define FNCCAST_CRYPT(f) ((void(*)(void*, byte*, byte*))(f)) | |
| 40 | |
| 41 #define IDEA_KEYSIZE 16 | |
| 42 #define IDEA_BLOCKSIZE 8 | |
| 43 #define IDEA_ROUNDS 8 | |
| 44 #define IDEA_KEYLEN (6*IDEA_ROUNDS+4) | |
| 45 | |
| 46 typedef struct { | |
| 47 u16 ek[IDEA_KEYLEN]; | |
| 48 u16 dk[IDEA_KEYLEN]; | |
| 49 int have_dk; | |
| 50 } IDEA_context; | |
| 51 | |
| 52 static u16 | |
| 53 mul_inv( u16 x ) | |
| 54 { | |
| 55 u16 t0, t1; | |
| 56 u16 q, y; | |
| 57 | |
| 58 if( x < 2 ) | |
| 59 return x; | |
| 60 t1 = 0x10001L / x; | |
| 61 y = 0x10001L % x; | |
| 62 if( y == 1 ) | |
| 63 return (1-t1) & 0xffff; | |
| 64 | |
| 65 t0 = 1; | |
| 66 do { | |
| 67 q = x / y; | |
| 68 x = x % y; | |
| 69 t0 += q * t1; | |
| 70 if( x == 1 ) | |
| 71 return t0; | |
| 72 q = y / x; | |
| 73 y = y % x; | |
| 74 t1 += q * t0; | |
| 75 } while( y != 1 ); | |
| 76 return (1-t1) & 0xffff; | |
| 77 } | |
| 78 | |
| 79 static void | |
| 80 cipher( byte *outbuf, const byte *inbuf, u16 *key ) | |
| 81 { | |
| 82 u16 x1, x2, x3,x4, s2, s3; | |
| 83 u16 *in, *out; | |
| 84 int r = IDEA_ROUNDS; | |
| 85 #define MUL(x,y) \ | |
| 86 do {u16 _t16; u32 _t32; \ | |
| 87 if( (_t16 = (y)) ) { \ | |
| 88 if( (x = (x)&0xffff) ) { \ | |
| 89 _t32 = (u32)x * _t16; \ | |
| 90 x = _t32 & 0xffff; \ | |
| 91 _t16 = _t32 >> 16; \ | |
| 92 x = ((x)-_t16) + (x<_t16?1:0); \ | |
| 93 } \ | |
| 94 else { \ | |
| 95 x = 1 - _t16; \ | |
| 96 } \ | |
| 97 } \ | |
| 98 else { \ | |
| 99 x = 1 - x; \ | |
| 100 } \ | |
| 101 } while(0) | |
| 102 | |
| 103 in = (u16*)inbuf; | |
| 104 x1 = *in++; | |
| 105 x2 = *in++; | |
| 106 x3 = *in++; | |
| 107 x4 = *in; | |
| 108 #ifdef LITTLE_ENDIAN_HOST | |
| 109 x1 = (x1>>8) | (x1<<8); | |
| 110 x2 = (x2>>8) | (x2<<8); | |
| 111 x3 = (x3>>8) | (x3<<8); | |
| 112 x4 = (x4>>8) | (x4<<8); | |
| 113 #endif | |
| 114 do { | |
| 115 MUL(x1, *key++); | |
| 116 x2 += *key++; | |
| 117 x3 += *key++; | |
| 118 MUL(x4, *key++ ); | |
| 119 | |
| 120 s3 = x3; | |
| 121 x3 ^= x1; | |
| 122 MUL(x3, *key++); | |
| 123 s2 = x2; | |
| 124 x2 ^=x4; | |
| 125 x2 += x3; | |
| 126 MUL(x2, *key++); | |
| 127 x3 += x2; | |
| 128 | |
| 129 x1 ^= x2; | |
| 130 x4 ^= x3; | |
| 131 | |
| 132 x2 ^= s3; | |
| 133 x3 ^= s2; | |
| 134 } while( --r ); | |
| 135 MUL(x1, *key++); | |
| 136 x3 += *key++; | |
| 137 x2 += *key++; | |
| 138 MUL(x4, *key); | |
| 139 | |
| 140 out = (u16*)outbuf; | |
| 141 #ifdef LITTLE_ENDIAN_HOST | |
| 142 *out++ = (x1>>8) | (x1<<8); | |
| 143 *out++ = (x3>>8) | (x3<<8); | |
| 144 *out++ = (x2>>8) | (x2<<8); | |
| 145 *out = (x4>>8) | (x4<<8); | |
| 146 #else | |
| 147 *out++ = x1; | |
| 148 *out++ = x3; | |
| 149 *out++ = x2; | |
| 150 *out = x4; | |
| 151 #endif | |
| 152 #undef MUL | |
| 153 } | |
| 154 | |
| 155 static void | |
| 156 expand_key( const byte *userkey, u16 *ek ) | |
| 157 { | |
| 158 int i,j; | |
| 159 | |
| 160 for(j=0; j < 8; j++ ) { | |
| 161 ek[j] = (*userkey << 8) + userkey[1]; | |
| 162 userkey += 2; | |
| 163 } | |
| 164 for(i=0; j < IDEA_KEYLEN; j++ ) { | |
| 165 i++; | |
| 166 ek[i+7] = ek[i&7] << 9 | ek[(i+1)&7] >> 7; | |
| 167 ek += i & 8; | |
| 168 i &= 7; | |
| 169 } | |
| 170 } | |
| 171 | |
| 172 static void | |
| 173 invert_key( u16 *ek, u16 dk[IDEA_KEYLEN] ) | |
| 174 { | |
| 175 int i; | |
| 176 u16 t1, t2, t3; | |
| 177 u16 temp[IDEA_KEYLEN]; | |
| 178 u16 *p = temp + IDEA_KEYLEN; | |
| 179 | |
| 180 t1 = mul_inv( *ek++ ); | |
| 181 t2 = -*ek++; | |
| 182 t3 = -*ek++; | |
| 183 *--p = mul_inv( *ek++ ); | |
| 184 *--p = t3; | |
| 185 *--p = t2; | |
| 186 *--p = t1; | |
| 187 | |
| 188 for(i=0; i < IDEA_ROUNDS-1; i++ ) { | |
| 189 t1 = *ek++; | |
| 190 *--p = *ek++; | |
| 191 *--p = t1; | |
| 192 | |
| 193 t1 = mul_inv( *ek++ ); | |
| 194 t2 = -*ek++; | |
| 195 t3 = -*ek++; | |
| 196 *--p = mul_inv( *ek++ ); | |
| 197 *--p = t2; | |
| 198 *--p = t3; | |
| 199 *--p = t1; | |
| 200 } | |
| 201 t1 = *ek++; | |
| 202 *--p = *ek++; | |
| 203 *--p = t1; | |
| 204 | |
| 205 t1 = mul_inv( *ek++ ); | |
| 206 t2 = -*ek++; | |
| 207 t3 = -*ek++; | |
| 208 *--p = mul_inv( *ek++ ); | |
| 209 *--p = t3; | |
| 210 *--p = t2; | |
| 211 *--p = t1; | |
| 212 memcpy(dk, temp, sizeof(temp) ); | |
| 213 memset(temp, 0, sizeof(temp) ); /* burn temp */ | |
| 214 } | |
| 215 | |
| 216 static int | |
| 217 do_idea_setkey( IDEA_context *c, const byte *key, unsigned int keylen ) | |
| 218 { | |
| 219 assert(keylen == 16); | |
| 220 c->have_dk = 0; | |
| 221 expand_key( key, c->ek ); | |
| 222 invert_key( c->ek, c->dk ); | |
| 223 return 0; | |
| 224 } | |
| 225 | |
| 226 static gcry_err_code_t | |
| 227 idea_setkey (void *context, const byte *key, unsigned int keylen) | |
| 228 { | |
| 229 IDEA_context *ctx = context; | |
| 230 int rc = do_idea_setkey (ctx, key, keylen); | |
| 231 _gcry_burn_stack (23+6*sizeof(void*)); | |
| 232 return rc; | |
| 233 } | |
| 234 | |
| 235 static void | |
| 236 do_idea_encrypt( IDEA_context *c, byte *outbuf, const byte *inbuf ) | |
| 237 { | |
| 238 cipher( outbuf, inbuf, c->ek ); | |
| 239 } | |
| 240 | |
| 241 static void | |
| 242 idea_encrypt (void *context, byte *out, const byte *in) | |
| 243 { | |
| 244 IDEA_context *ctx = context; | |
| 245 do_idea_encrypt (ctx, out, in); | |
| 246 _gcry_burn_stack (24+3*sizeof (void*)); | |
| 247 } | |
| 248 | |
| 249 static void | |
| 250 do_idea_decrypt( IDEA_context *c, byte *outbuf, const byte *inbuf ) | |
| 251 { | |
| 252 if( !c->have_dk ) { | |
| 253 c->have_dk = 1; | |
| 254 invert_key( c->ek, c->dk ); | |
| 255 } | |
| 256 cipher( outbuf, inbuf, c->dk ); | |
| 257 } | |
| 258 | |
| 259 static void | |
| 260 idea_decrypt (void *context, byte *out, const byte *in) | |
| 261 { | |
| 262 IDEA_context *ctx = context; | |
| 263 | |
| 264 do_idea_decrypt (ctx, out, in); | |
| 265 _gcry_burn_stack (24+3*sizeof (void*)); | |
| 266 } | |
| 267 | |
| 268 gcry_cipher_spec_t _gcry_cipher_spec_idea = | |
| 269 { | |
| 270 "IDEA", NULL, NULL, IDEA_BLOCKSIZE, 128, sizeof (IDEA_context), | |
| 271 idea_setkey, idea_encrypt, idea_decrypt, | |
| 272 }; |
