1 /* 2 * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org> 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining 5 * a copy of this software and associated documentation files (the 6 * "Software"), to deal in the Software without restriction, including 7 * without limitation the rights to use, copy, modify, merge, publish, 8 * distribute, sublicense, and/or sell copies of the Software, and to 9 * permit persons to whom the Software is furnished to do so, subject to 10 * the following conditions: 11 * 12 * The above copyright notice and this permission notice shall be 13 * included in all copies or substantial portions of the Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 22 * SOFTWARE. 23 */ 24 25 #include "inner.h" 26 27 /* see inner.h */ 28 void 29 br_aes_ct_bitslice_Sbox(uint32_t *q) 30 { 31 /* 32 * This S-box implementation is a straightforward translation of 33 * the circuit described by Boyar and Peralta in "A new 34 * combinational logic minimization technique with applications 35 * to cryptology" (https://eprint.iacr.org/2009/191.pdf). 36 * 37 * Note that variables x* (input) and s* (output) are numbered 38 * in "reverse" order (x0 is the high bit, x7 is the low bit). 39 */ 40 41 uint32_t x0, x1, x2, x3, x4, x5, x6, x7; 42 uint32_t y1, y2, y3, y4, y5, y6, y7, y8, y9; 43 uint32_t y10, y11, y12, y13, y14, y15, y16, y17, y18, y19; 44 uint32_t y20, y21; 45 uint32_t z0, z1, z2, z3, z4, z5, z6, z7, z8, z9; 46 uint32_t z10, z11, z12, z13, z14, z15, z16, z17; 47 uint32_t t0, t1, t2, t3, t4, t5, t6, t7, t8, t9; 48 uint32_t t10, t11, t12, t13, t14, t15, t16, t17, t18, t19; 49 uint32_t t20, t21, t22, t23, t24, t25, t26, t27, t28, t29; 50 uint32_t t30, t31, t32, t33, t34, t35, t36, t37, t38, t39; 51 uint32_t t40, t41, t42, t43, t44, t45, t46, t47, t48, t49; 52 uint32_t t50, t51, t52, t53, t54, t55, t56, t57, t58, t59; 53 uint32_t t60, t61, t62, t63, t64, t65, t66, t67; 54 uint32_t s0, s1, s2, s3, s4, s5, s6, s7; 55 56 x0 = q[7]; 57 x1 = q[6]; 58 x2 = q[5]; 59 x3 = q[4]; 60 x4 = q[3]; 61 x5 = q[2]; 62 x6 = q[1]; 63 x7 = q[0]; 64 65 /* 66 * Top linear transformation. 67 */ 68 y14 = x3 ^ x5; 69 y13 = x0 ^ x6; 70 y9 = x0 ^ x3; 71 y8 = x0 ^ x5; 72 t0 = x1 ^ x2; 73 y1 = t0 ^ x7; 74 y4 = y1 ^ x3; 75 y12 = y13 ^ y14; 76 y2 = y1 ^ x0; 77 y5 = y1 ^ x6; 78 y3 = y5 ^ y8; 79 t1 = x4 ^ y12; 80 y15 = t1 ^ x5; 81 y20 = t1 ^ x1; 82 y6 = y15 ^ x7; 83 y10 = y15 ^ t0; 84 y11 = y20 ^ y9; 85 y7 = x7 ^ y11; 86 y17 = y10 ^ y11; 87 y19 = y10 ^ y8; 88 y16 = t0 ^ y11; 89 y21 = y13 ^ y16; 90 y18 = x0 ^ y16; 91 92 /* 93 * Non-linear section. 94 */ 95 t2 = y12 & y15; 96 t3 = y3 & y6; 97 t4 = t3 ^ t2; 98 t5 = y4 & x7; 99 t6 = t5 ^ t2; 100 t7 = y13 & y16; 101 t8 = y5 & y1; 102 t9 = t8 ^ t7; 103 t10 = y2 & y7; 104 t11 = t10 ^ t7; 105 t12 = y9 & y11; 106 t13 = y14 & y17; 107 t14 = t13 ^ t12; 108 t15 = y8 & y10; 109 t16 = t15 ^ t12; 110 t17 = t4 ^ t14; 111 t18 = t6 ^ t16; 112 t19 = t9 ^ t14; 113 t20 = t11 ^ t16; 114 t21 = t17 ^ y20; 115 t22 = t18 ^ y19; 116 t23 = t19 ^ y21; 117 t24 = t20 ^ y18; 118 119 t25 = t21 ^ t22; 120 t26 = t21 & t23; 121 t27 = t24 ^ t26; 122 t28 = t25 & t27; 123 t29 = t28 ^ t22; 124 t30 = t23 ^ t24; 125 t31 = t22 ^ t26; 126 t32 = t31 & t30; 127 t33 = t32 ^ t24; 128 t34 = t23 ^ t33; 129 t35 = t27 ^ t33; 130 t36 = t24 & t35; 131 t37 = t36 ^ t34; 132 t38 = t27 ^ t36; 133 t39 = t29 & t38; 134 t40 = t25 ^ t39; 135 136 t41 = t40 ^ t37; 137 t42 = t29 ^ t33; 138 t43 = t29 ^ t40; 139 t44 = t33 ^ t37; 140 t45 = t42 ^ t41; 141 z0 = t44 & y15; 142 z1 = t37 & y6; 143 z2 = t33 & x7; 144 z3 = t43 & y16; 145 z4 = t40 & y1; 146 z5 = t29 & y7; 147 z6 = t42 & y11; 148 z7 = t45 & y17; 149 z8 = t41 & y10; 150 z9 = t44 & y12; 151 z10 = t37 & y3; 152 z11 = t33 & y4; 153 z12 = t43 & y13; 154 z13 = t40 & y5; 155 z14 = t29 & y2; 156 z15 = t42 & y9; 157 z16 = t45 & y14; 158 z17 = t41 & y8; 159 160 /* 161 * Bottom linear transformation. 162 */ 163 t46 = z15 ^ z16; 164 t47 = z10 ^ z11; 165 t48 = z5 ^ z13; 166 t49 = z9 ^ z10; 167 t50 = z2 ^ z12; 168 t51 = z2 ^ z5; 169 t52 = z7 ^ z8; 170 t53 = z0 ^ z3; 171 t54 = z6 ^ z7; 172 t55 = z16 ^ z17; 173 t56 = z12 ^ t48; 174 t57 = t50 ^ t53; 175 t58 = z4 ^ t46; 176 t59 = z3 ^ t54; 177 t60 = t46 ^ t57; 178 t61 = z14 ^ t57; 179 t62 = t52 ^ t58; 180 t63 = t49 ^ t58; 181 t64 = z4 ^ t59; 182 t65 = t61 ^ t62; 183 t66 = z1 ^ t63; 184 s0 = t59 ^ t63; 185 s6 = t56 ^ ~t62; 186 s7 = t48 ^ ~t60; 187 t67 = t64 ^ t65; 188 s3 = t53 ^ t66; 189 s4 = t51 ^ t66; 190 s5 = t47 ^ t65; 191 s1 = t64 ^ ~s3; 192 s2 = t55 ^ ~t67; 193 194 q[7] = s0; 195 q[6] = s1; 196 q[5] = s2; 197 q[4] = s3; 198 q[3] = s4; 199 q[2] = s5; 200 q[1] = s6; 201 q[0] = s7; 202 } 203 204 /* see inner.h */ 205 void 206 br_aes_ct_ortho(uint32_t *q) 207 { 208 #define SWAPN(cl, ch, s, x, y) do { \ 209 uint32_t a, b; \ 210 a = (x); \ 211 b = (y); \ 212 (x) = (a & (uint32_t)cl) | ((b & (uint32_t)cl) << (s)); \ 213 (y) = ((a & (uint32_t)ch) >> (s)) | (b & (uint32_t)ch); \ 214 } while (0) 215 216 #define SWAP2(x, y) SWAPN(0x55555555, 0xAAAAAAAA, 1, x, y) 217 #define SWAP4(x, y) SWAPN(0x33333333, 0xCCCCCCCC, 2, x, y) 218 #define SWAP8(x, y) SWAPN(0x0F0F0F0F, 0xF0F0F0F0, 4, x, y) 219 220 SWAP2(q[0], q[1]); 221 SWAP2(q[2], q[3]); 222 SWAP2(q[4], q[5]); 223 SWAP2(q[6], q[7]); 224 225 SWAP4(q[0], q[2]); 226 SWAP4(q[1], q[3]); 227 SWAP4(q[4], q[6]); 228 SWAP4(q[5], q[7]); 229 230 SWAP8(q[0], q[4]); 231 SWAP8(q[1], q[5]); 232 SWAP8(q[2], q[6]); 233 SWAP8(q[3], q[7]); 234 } 235 236 static const unsigned char Rcon[] = { 237 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1B, 0x36 238 }; 239 240 static uint32_t 241 sub_word(uint32_t x) 242 { 243 uint32_t q[8]; 244 int i; 245 246 for (i = 0; i < 8; i ++) { 247 q[i] = x; 248 } 249 br_aes_ct_ortho(q); 250 br_aes_ct_bitslice_Sbox(q); 251 br_aes_ct_ortho(q); 252 return q[0]; 253 } 254 255 /* see inner.h */ 256 unsigned 257 br_aes_ct_keysched(uint32_t *comp_skey, const void *key, size_t key_len) 258 { 259 unsigned num_rounds; 260 int i, j, k, nk, nkf; 261 uint32_t tmp; 262 uint32_t skey[120]; 263 264 switch (key_len) { 265 case 16: 266 num_rounds = 10; 267 break; 268 case 24: 269 num_rounds = 12; 270 break; 271 case 32: 272 num_rounds = 14; 273 break; 274 default: 275 /* abort(); */ 276 return 0; 277 } 278 nk = (int)(key_len >> 2); 279 nkf = (int)((num_rounds + 1) << 2); 280 tmp = 0; 281 for (i = 0; i < nk; i ++) { 282 tmp = br_dec32le((const unsigned char *)key + (i << 2)); 283 skey[(i << 1) + 0] = tmp; 284 skey[(i << 1) + 1] = tmp; 285 } 286 for (i = nk, j = 0, k = 0; i < nkf; i ++) { 287 if (j == 0) { 288 tmp = (tmp << 24) | (tmp >> 8); 289 tmp = sub_word(tmp) ^ Rcon[k]; 290 } else if (nk > 6 && j == 4) { 291 tmp = sub_word(tmp); 292 } 293 tmp ^= skey[(i - nk) << 1]; 294 skey[(i << 1) + 0] = tmp; 295 skey[(i << 1) + 1] = tmp; 296 if (++ j == nk) { 297 j = 0; 298 k ++; 299 } 300 } 301 for (i = 0; i < nkf; i += 4) { 302 br_aes_ct_ortho(skey + (i << 1)); 303 } 304 for (i = 0, j = 0; i < nkf; i ++, j += 2) { 305 comp_skey[i] = (skey[j + 0] & 0x55555555) 306 | (skey[j + 1] & 0xAAAAAAAA); 307 } 308 return num_rounds; 309 } 310 311 /* see inner.h */ 312 void 313 br_aes_ct_skey_expand(uint32_t *skey, 314 unsigned num_rounds, const uint32_t *comp_skey) 315 { 316 unsigned u, v, n; 317 318 n = (num_rounds + 1) << 2; 319 for (u = 0, v = 0; u < n; u ++, v += 2) { 320 uint32_t x, y; 321 322 x = y = comp_skey[u]; 323 x &= 0x55555555; 324 skey[v + 0] = x | (x << 1); 325 y &= 0xAAAAAAAA; 326 skey[v + 1] = y | (y >> 1); 327 } 328 } 329