Tristan Matthews | 0a329cc | 2013-07-17 13:20:14 -0400 | [diff] [blame] | 1 | /* |
| 2 | * aes_tables.c |
| 3 | * |
| 4 | * generate tables for the AES cipher |
| 5 | * |
| 6 | * David A. McGrew |
| 7 | * Cisco Systems, Inc. |
| 8 | */ |
| 9 | /* |
| 10 | * |
| 11 | * Copyright(c) 2001-2006 Cisco Systems, Inc. |
| 12 | * All rights reserved. |
| 13 | * |
| 14 | * Redistribution and use in source and binary forms, with or without |
| 15 | * modification, are permitted provided that the following conditions |
| 16 | * are met: |
| 17 | * |
| 18 | * Redistributions of source code must retain the above copyright |
| 19 | * notice, this list of conditions and the following disclaimer. |
| 20 | * |
| 21 | * Redistributions in binary form must reproduce the above |
| 22 | * copyright notice, this list of conditions and the following |
| 23 | * disclaimer in the documentation and/or other materials provided |
| 24 | * with the distribution. |
| 25 | * |
| 26 | * Neither the name of the Cisco Systems, Inc. nor the names of its |
| 27 | * contributors may be used to endorse or promote products derived |
| 28 | * from this software without specific prior written permission. |
| 29 | * |
| 30 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 31 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 32 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| 33 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| 34 | * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, |
| 35 | * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| 36 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| 37 | * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 38 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| 39 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 40 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
| 41 | * OF THE POSSIBILITY OF SUCH DAMAGE. |
| 42 | * |
| 43 | */ |
| 44 | |
| 45 | #include <stdio.h> |
| 46 | #include "gf2_8.h" |
| 47 | #include "crypto_math.h" |
| 48 | |
| 49 | |
| 50 | unsigned char aes_sbox[256]; |
| 51 | |
| 52 | unsigned char aes_inv_sbox[256]; |
| 53 | |
| 54 | uint32_t T0[256], T1[256], T2[256], T3[256], T4[256]; |
| 55 | |
| 56 | |
| 57 | #define AES_INVERSE_TEST 0 /* set to 1 to test forward/backwards aes */ |
| 58 | |
| 59 | /* functions for precomputing AES values */ |
| 60 | |
| 61 | /* |
| 62 | * A[] is the 8 x 8 binary matrix (represented as an array of columns, |
| 63 | * where each column is an octet) which defines the affine |
| 64 | * transformation used in the AES substitution table (Section |
| 65 | * 4.2.1 of the spec). |
| 66 | */ |
| 67 | |
| 68 | uint8_t A[8] = { 31, 62, 124, 248, 241, 227, 199, 143 }; |
| 69 | |
| 70 | /* |
| 71 | * b is the 8 bit vector (represented as an octet) used in the affine |
| 72 | * transform described above. |
| 73 | */ |
| 74 | |
| 75 | uint8_t b = 99; |
| 76 | |
| 77 | |
| 78 | void |
| 79 | aes_init_sbox(void) { |
| 80 | unsigned int i; |
| 81 | uint8_t x; |
| 82 | |
| 83 | for (i=0; i < 256; i++) { |
| 84 | x = gf2_8_compute_inverse((gf2_8)i); |
| 85 | x = A_times_x_plus_b(A, x, b); |
| 86 | aes_sbox[i] = x; |
| 87 | aes_inv_sbox[x] = i; |
| 88 | } |
| 89 | } |
| 90 | |
| 91 | void |
| 92 | aes_compute_tables(void) { |
| 93 | int i; |
| 94 | uint32_t x1, x2, x3; |
| 95 | v32_t tmp; |
| 96 | |
| 97 | /* initialize substitution table */ |
| 98 | aes_init_sbox(); |
| 99 | |
| 100 | /* combine sbox with linear operations to form 8-bit to 32-bit tables */ |
| 101 | for (i=0; i < 256; i++) { |
| 102 | x1 = aes_sbox[i]; |
| 103 | x2 = gf2_8_shift(x1); |
| 104 | x3 = x2 ^ x1; |
| 105 | |
| 106 | tmp.v8[0] = x2; |
| 107 | tmp.v8[1] = x1; |
| 108 | tmp.v8[2] = x1; |
| 109 | tmp.v8[3] = x3; |
| 110 | T0[i] = tmp.value; |
| 111 | |
| 112 | tmp.v8[0] = x3; |
| 113 | tmp.v8[1] = x2; |
| 114 | tmp.v8[2] = x1; |
| 115 | tmp.v8[3] = x1; |
| 116 | T1[i] = tmp.value; |
| 117 | |
| 118 | tmp.v8[0] = x1; |
| 119 | tmp.v8[1] = x3; |
| 120 | tmp.v8[2] = x2; |
| 121 | tmp.v8[3] = x1; |
| 122 | T2[i] = tmp.value; |
| 123 | |
| 124 | tmp.v8[0] = x1; |
| 125 | tmp.v8[1] = x1; |
| 126 | tmp.v8[2] = x3; |
| 127 | tmp.v8[3] = x2; |
| 128 | T3[i] = tmp.value; |
| 129 | |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | |
| 134 | /* |
| 135 | * the tables U0, U1, U2, U3 implement the aes operations invSubBytes, |
| 136 | * invMixColumns, and invShiftRows |
| 137 | */ |
| 138 | |
| 139 | uint32_t U0[256], U1[256], U2[256], U3[256], U4[256]; |
| 140 | |
| 141 | extern uint8_t aes_inv_sbox[256]; |
| 142 | |
| 143 | void |
| 144 | aes_compute_inv_tables(void) { |
| 145 | int i; |
| 146 | uint8_t x, xe, x9, xd, xb; |
| 147 | v32_t tmp; |
| 148 | |
| 149 | /* combine sbox with linear operations to form 8-bit to 32-bit tables */ |
| 150 | for (i=0; i < 256; i++) { |
| 151 | x = aes_inv_sbox[i]; |
| 152 | |
| 153 | xe = gf2_8_multiply(0x0e, x); |
| 154 | x9 = gf2_8_multiply(0x09, x); |
| 155 | xd = gf2_8_multiply(0x0d, x); |
| 156 | xb = gf2_8_multiply(0x0b, x); |
| 157 | |
| 158 | tmp.v8[0] = xe; |
| 159 | tmp.v8[1] = x9; |
| 160 | tmp.v8[2] = xd; |
| 161 | tmp.v8[3] = xb; |
| 162 | U0[i] = tmp.value; |
| 163 | |
| 164 | tmp.v8[0] = xb; |
| 165 | tmp.v8[1] = xe; |
| 166 | tmp.v8[2] = x9; |
| 167 | tmp.v8[3] = xd; |
| 168 | U1[i] = tmp.value; |
| 169 | |
| 170 | tmp.v8[0] = xd; |
| 171 | tmp.v8[1] = xb; |
| 172 | tmp.v8[2] = xe; |
| 173 | tmp.v8[3] = x9; |
| 174 | U2[i] = tmp.value; |
| 175 | |
| 176 | tmp.v8[0] = x9; |
| 177 | tmp.v8[1] = xd; |
| 178 | tmp.v8[2] = xb; |
| 179 | tmp.v8[3] = xe; |
| 180 | U3[i] = tmp.value; |
| 181 | |
| 182 | tmp.v8[0] = tmp.v8[1] = tmp.v8[2] = tmp.v8[3] = x; |
| 183 | U4[i] = tmp.value; |
| 184 | } |
| 185 | } |
| 186 | |
| 187 | |
| 188 | /* |
| 189 | * aes_test_inverse() returns err_status_ok if aes |
| 190 | * encryption and decryption are true inverses of each other, and |
| 191 | * returns err_status_algo_fail otherwise |
| 192 | */ |
| 193 | |
| 194 | #include "err.h" |
| 195 | |
| 196 | err_status_t |
| 197 | aes_test_inverse(void); |
| 198 | |
| 199 | #define TABLES_32BIT 1 |
| 200 | |
| 201 | int |
| 202 | main(void) { |
| 203 | int i; |
| 204 | |
| 205 | aes_init_sbox(); |
| 206 | aes_compute_inv_tables(); |
| 207 | |
| 208 | #if TABLES_32BIT |
| 209 | printf("uint32_t U0 = {"); |
| 210 | for (i=0; i < 256; i++) { |
| 211 | if ((i % 4) == 0) |
| 212 | printf("\n"); |
| 213 | printf("0x%0x, ", U0[i]); |
| 214 | } |
| 215 | printf("\n}\n"); |
| 216 | |
| 217 | printf("uint32_t U1 = {"); |
| 218 | for (i=0; i < 256; i++) { |
| 219 | if ((i % 4) == 0) |
| 220 | printf("\n"); |
| 221 | printf("0x%x, ", U1[i]); |
| 222 | } |
| 223 | printf("\n}\n"); |
| 224 | |
| 225 | printf("uint32_t U2 = {"); |
| 226 | for (i=0; i < 256; i++) { |
| 227 | if ((i % 4) == 0) |
| 228 | printf("\n"); |
| 229 | printf("0x%x, ", U2[i]); |
| 230 | } |
| 231 | printf("\n}\n"); |
| 232 | |
| 233 | printf("uint32_t U3 = {"); |
| 234 | for (i=0; i < 256; i++) { |
| 235 | if ((i % 4) == 0) |
| 236 | printf("\n"); |
| 237 | printf("0x%x, ", U3[i]); |
| 238 | } |
| 239 | printf("\n}\n"); |
| 240 | |
| 241 | printf("uint32_t U4 = {"); |
| 242 | for (i=0; i < 256; i++) { |
| 243 | if ((i % 4) == 0) |
| 244 | printf("\n"); |
| 245 | printf("0x%x, ", U4[i]); |
| 246 | } |
| 247 | printf("\n}\n"); |
| 248 | |
| 249 | #else |
| 250 | |
| 251 | printf("uint32_t U0 = {"); |
| 252 | for (i=0; i < 256; i++) { |
| 253 | if ((i % 4) == 0) |
| 254 | printf("\n"); |
| 255 | printf("0x%lx, ", U0[i]); |
| 256 | } |
| 257 | printf("\n}\n"); |
| 258 | |
| 259 | printf("uint32_t U1 = {"); |
| 260 | for (i=0; i < 256; i++) { |
| 261 | if ((i % 4) == 0) |
| 262 | printf("\n"); |
| 263 | printf("0x%lx, ", U1[i]); |
| 264 | } |
| 265 | printf("\n}\n"); |
| 266 | |
| 267 | printf("uint32_t U2 = {"); |
| 268 | for (i=0; i < 256; i++) { |
| 269 | if ((i % 4) == 0) |
| 270 | printf("\n"); |
| 271 | printf("0x%lx, ", U2[i]); |
| 272 | } |
| 273 | printf("\n}\n"); |
| 274 | |
| 275 | printf("uint32_t U3 = {"); |
| 276 | for (i=0; i < 256; i++) { |
| 277 | if ((i % 4) == 0) |
| 278 | printf("\n"); |
| 279 | printf("0x%lx, ", U3[i]); |
| 280 | } |
| 281 | printf("\n}\n"); |
| 282 | |
| 283 | printf("uint32_t U4 = {"); |
| 284 | for (i=0; i < 256; i++) { |
| 285 | if ((i % 4) == 0) |
| 286 | printf("\n"); |
| 287 | printf("0x%lx, ", U4[i]); |
| 288 | } |
| 289 | printf("\n}\n"); |
| 290 | |
| 291 | |
| 292 | #endif /* TABLES_32BIT */ |
| 293 | |
| 294 | |
| 295 | #if AES_INVERSE_TEST |
| 296 | /* |
| 297 | * test that aes_encrypt and aes_decrypt are actually |
| 298 | * inverses of each other |
| 299 | */ |
| 300 | |
| 301 | printf("aes inverse test: "); |
| 302 | if (aes_test_inverse() == err_status_ok) |
| 303 | printf("passed\n"); |
| 304 | else { |
| 305 | printf("failed\n"); |
| 306 | exit(1); |
| 307 | } |
| 308 | #endif |
| 309 | |
| 310 | return 0; |
| 311 | } |
| 312 | |
| 313 | #if AES_INVERSE_TEST |
| 314 | |
| 315 | err_status_t |
| 316 | aes_test_inverse(void) { |
| 317 | v128_t x, y; |
| 318 | aes_expanded_key_t expanded_key, decrypt_key; |
| 319 | uint8_t plaintext[16] = { |
| 320 | 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, |
| 321 | 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff |
| 322 | }; |
| 323 | uint8_t key[16] = { |
| 324 | 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, |
| 325 | 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f |
| 326 | }; |
| 327 | v128_t k; |
| 328 | v128_set_to_zero(&x); |
| 329 | |
| 330 | v128_copy_octet_string(&k, key); |
| 331 | v128_copy_octet_string(&x, plaintext); |
| 332 | aes_expand_encryption_key(k, expanded_key); |
| 333 | aes_expand_decryption_key(k, decrypt_key); |
| 334 | aes_encrypt(&x, expanded_key); |
| 335 | aes_decrypt(&x, decrypt_key); |
| 336 | |
| 337 | /* compare to expected value then report */ |
| 338 | v128_copy_octet_string(&y, plaintext); |
| 339 | |
| 340 | if (v128_is_eq(&x, &y)) |
| 341 | return err_status_ok; |
| 342 | return err_status_algo_fail; |
| 343 | |
| 344 | } |
| 345 | |
| 346 | #endif |