| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * The SHA3 algorithm family |
| 4 | * |
| 5 | * (c) 2017 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of secnet. |
| 11 | * See README for full list of copyright holders. |
| 12 | * |
| 13 | * secnet is free software; you can redistribute it and/or modify it |
| 14 | * under the terms of the GNU General Public License as published by |
| 15 | * the Free Software Foundation; either version d of the License, or |
| 16 | * (at your option) any later version. |
| 17 | * |
| 18 | * secnet is distributed in the hope that it will be useful, but |
| 19 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 21 | * General Public License for more details. |
| 22 | * |
| 23 | * You should have received a copy of the GNU General Public License |
| 24 | * version 3 along with secnet; if not, see |
| 25 | * https://www.gnu.org/licenses/gpl.html. |
| 26 | * |
| 27 | * This file was originally part of Catacomb, but has been automatically |
| 28 | * modified for incorporation into secnet: see `import-catacomb-crypto' |
| 29 | * for details. |
| 30 | * |
| 31 | * Catacomb is free software; you can redistribute it and/or modify |
| 32 | * it under the terms of the GNU Library General Public License as |
| 33 | * published by the Free Software Foundation; either version 2 of the |
| 34 | * License, or (at your option) any later version. |
| 35 | * |
| 36 | * Catacomb is distributed in the hope that it will be useful, |
| 37 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 38 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 39 | * GNU Library General Public License for more details. |
| 40 | * |
| 41 | * You should have received a copy of the GNU Library General Public |
| 42 | * License along with Catacomb; if not, write to the Free |
| 43 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 44 | * MA 02111-1307, USA. |
| 45 | */ |
| 46 | |
| 47 | /*----- Header files ------------------------------------------------------*/ |
| 48 | |
| 49 | #include <assert.h> |
| 50 | #include <stdarg.h> |
| 51 | #include <string.h> |
| 52 | |
| 53 | #include "sha3.h" |
| 54 | |
| 55 | /*----- General utilities -------------------------------------------------*/ |
| 56 | |
| 57 | static void absorb(sha3_ctx *ctx, const octet *p, unsigned r) |
| 58 | { |
| 59 | kludge64 t[25]; |
| 60 | unsigned i; |
| 61 | |
| 62 | /* memdump("absorb", p, 8*r, 0); */ |
| 63 | for (i = 0; i < r; i++) { LOAD64_L_(t[i], p); p += 8; } |
| 64 | keccak1600_mix(&ctx->s, t, r); |
| 65 | } |
| 66 | |
| 67 | static void step(sha3_ctx *ctx) { keccak1600_p(&ctx->s, &ctx->s, 24); } |
| 68 | |
| 69 | static void pad(sha3_ctx *ctx, unsigned lo, unsigned hi) |
| 70 | { |
| 71 | size_t spare = ctx->r - ctx->n; |
| 72 | |
| 73 | if (spare == 1) |
| 74 | ctx->buf[ctx->n] = lo | hi; |
| 75 | else { |
| 76 | ctx->buf[ctx->n] = lo; |
| 77 | ctx->buf[ctx->r - 1] = hi; |
| 78 | memset(ctx->buf + ctx->n + 1, 0, spare - 2); |
| 79 | } |
| 80 | absorb(ctx, ctx->buf, ctx->r/8); |
| 81 | } |
| 82 | |
| 83 | static void squeeze(sha3_ctx *ctx, octet *p, unsigned r) |
| 84 | { |
| 85 | kludge64 t[25]; |
| 86 | unsigned i; |
| 87 | |
| 88 | keccak1600_extract(&ctx->s, t, r); |
| 89 | for (i = 0; i < r; i++) { STORE64_L_(p, t[i]); p += 8; } |
| 90 | /* memdump("squeeze", p - 8*r, 8*r, 0); */ |
| 91 | } |
| 92 | |
| 93 | enum { |
| 94 | OP_CSHAKE = 0x04, |
| 95 | OP_SHA3 = 0x06, |
| 96 | OP_SHAKE = 0x1f |
| 97 | }; |
| 98 | |
| 99 | enum { ST_ABSORB, ST_SQUEEZE, ST_DEAD }; |
| 100 | |
| 101 | /*----- The SHA3 algorithms -----------------------------------------------*/ |
| 102 | |
| 103 | /* --- @sha3_{224,256,384,512}_init@ --- * |
| 104 | * |
| 105 | * Arguments: @sha3_ctx *ctx@ = pointer to context block to initialize |
| 106 | * |
| 107 | * Returns: --- |
| 108 | * |
| 109 | * Use: Initializes a SHA3 hashing context for use. |
| 110 | */ |
| 111 | |
| 112 | static void init_sha3(sha3_ctx *ctx, unsigned w) |
| 113 | { |
| 114 | keccak1600_init(&ctx->s); |
| 115 | ctx->w = w/8; ctx->r = (1600 - 2*w)/8; ctx->n = 0; |
| 116 | } |
| 117 | |
| 118 | void sha3_224_init(sha3_ctx *ctx) { init_sha3(ctx, 224); } |
| 119 | void sha3_256_init(sha3_ctx *ctx) { init_sha3(ctx, 256); } |
| 120 | void sha3_384_init(sha3_ctx *ctx) { init_sha3(ctx, 384); } |
| 121 | void sha3_512_init(sha3_ctx *ctx) { init_sha3(ctx, 512); } |
| 122 | |
| 123 | /* --- @sha3_hash@ --- * |
| 124 | * |
| 125 | * Arguments: @sha3_ctx *ctx@ = pointer to context bock |
| 126 | * @const void *p@ = pointer to data to hash |
| 127 | * @size_t sz@ = size of buffer to hash |
| 128 | * |
| 129 | * Returns: --- |
| 130 | * |
| 131 | * Use: Hashes a buffer of data. The buffer may be of any size and |
| 132 | * alignment. |
| 133 | */ |
| 134 | |
| 135 | void sha3_hash(sha3_ctx *ctx, const void *p, size_t sz) |
| 136 | { |
| 137 | const octet *q = p; |
| 138 | size_t spare = ctx->r - ctx->n; |
| 139 | |
| 140 | if (sz < spare) { |
| 141 | memcpy(ctx->buf + ctx->n, q, sz); |
| 142 | ctx->n += sz; |
| 143 | return; |
| 144 | } |
| 145 | if (ctx->n) { |
| 146 | memcpy(ctx->buf + ctx->n, q, spare); |
| 147 | absorb(ctx, ctx->buf, ctx->r/8); |
| 148 | step(ctx); |
| 149 | q += spare; sz -= spare; |
| 150 | } |
| 151 | while (sz >= ctx->r) { |
| 152 | absorb(ctx, q, ctx->r/8); |
| 153 | step(ctx); |
| 154 | q += ctx->r; sz -= ctx->r; |
| 155 | } |
| 156 | if (sz) memcpy(ctx->buf, q, sz); |
| 157 | ctx->n = sz; |
| 158 | } |
| 159 | |
| 160 | /* --- @sha3_done@ --- * |
| 161 | * |
| 162 | * Arguments: @sha3_ctx *ctx@ = pointer to context block |
| 163 | * @void *hash@ = pointer to output buffer |
| 164 | * |
| 165 | * Returns: --- |
| 166 | * |
| 167 | * Use: Returns the hash of the data read so far. |
| 168 | */ |
| 169 | |
| 170 | void sha3_done(sha3_ctx *ctx, void *hash) |
| 171 | { |
| 172 | pad(ctx, OP_SHA3, 0x80); |
| 173 | step(ctx); |
| 174 | |
| 175 | if (ctx->w%8 == 0) |
| 176 | squeeze(ctx, hash, ctx->w/8); |
| 177 | else { |
| 178 | squeeze(ctx, ctx->buf, (ctx->w + 7)/8); |
| 179 | memcpy(hash, ctx->buf, ctx->w); |
| 180 | } |
| 181 | } |
| 182 | |
| 183 | /*----- The cSHAKE XOF algorithm ------------------------------------------*/ |
| 184 | |
| 185 | static void leftenc_sz(shake_ctx *ctx, size_t n) |
| 186 | { |
| 187 | kludge64 t; |
| 188 | octet b[9]; |
| 189 | unsigned i; |
| 190 | |
| 191 | SET64(t, ((n&~(size_t)MASK32) >> 16) >> 16, n&MASK32); |
| 192 | STORE64_B_(b + 1, t); |
| 193 | for (i = 1; i < 8 && !b[i]; i++); |
| 194 | i--; b[i] = 8 - i; |
| 195 | shake_hash(ctx, b + i, 9 - i); |
| 196 | } |
| 197 | |
| 198 | static void stringenc(shake_ctx *ctx, const void *p, size_t sz) |
| 199 | { leftenc_sz(ctx, 8*sz); if (sz) shake_hash(ctx, p, sz); } |
| 200 | |
| 201 | static void bytepad_before(shake_ctx *ctx) |
| 202 | { leftenc_sz(ctx, ctx->h.r); } |
| 203 | |
| 204 | static void bytepad_after(shake_ctx *ctx) |
| 205 | { |
| 206 | unsigned pad; |
| 207 | |
| 208 | if (ctx->h.n%8) { |
| 209 | pad = 8 - ctx->h.n%8; |
| 210 | memset(ctx->h.buf + ctx->h.n, 0, pad); |
| 211 | ctx->h.n += pad; |
| 212 | } |
| 213 | if (ctx->h.n) { |
| 214 | absorb(&ctx->h, ctx->h.buf, ctx->h.n/8); |
| 215 | step(&ctx->h); ctx->h.n = 0; |
| 216 | } |
| 217 | } |
| 218 | |
| 219 | /* --- @cshake{128,256}_init@ --- * |
| 220 | * |
| 221 | * Arguments: @shake_ctx *ctx@ = pointer to context to initialize |
| 222 | * @const void *func@ = NIST-allocated function name |
| 223 | * @size_t fsz@ = length of function name |
| 224 | * @const void *perso@ = user personalization string |
| 225 | * @size_t psz@ = length of personalization string |
| 226 | * |
| 227 | * Returns: --- |
| 228 | * |
| 229 | * Use: Initializes a cSHAKE context. The context is initially in |
| 230 | * the `absorbing' state: feed it data with @shake_hash@. |
| 231 | */ |
| 232 | |
| 233 | static void init_shake(shake_ctx *ctx, unsigned c0, |
| 234 | const void *func, size_t fsz, |
| 235 | const void *perso, size_t psz) |
| 236 | { |
| 237 | keccak1600_init(&ctx->h.s); ctx->st = ST_ABSORB; |
| 238 | ctx->h.r = (1600 - 2*c0)/8; ctx->h.w = 0; ctx->h.n = 0; |
| 239 | if (!fsz && !psz) |
| 240 | ctx->op = OP_SHAKE; |
| 241 | else { |
| 242 | bytepad_before(ctx); |
| 243 | stringenc(ctx, func, fsz); |
| 244 | stringenc(ctx, perso, psz); |
| 245 | bytepad_after(ctx); |
| 246 | ctx->op = OP_CSHAKE; |
| 247 | } |
| 248 | } |
| 249 | |
| 250 | void cshake128_init(shake_ctx *ctx, |
| 251 | const void *func, size_t fsz, |
| 252 | const void *perso, size_t psz) |
| 253 | { init_shake(ctx, 128, func, fsz, perso, psz); } |
| 254 | |
| 255 | void cshake256_init(shake_ctx *ctx, |
| 256 | const void *func, size_t fsz, |
| 257 | const void *perso, size_t psz) |
| 258 | { init_shake(ctx, 256, func, fsz, perso, psz); } |
| 259 | |
| 260 | /* --- @shake{128,256}_init@ --- * |
| 261 | * |
| 262 | * Arguments: @sha3_ctx *ctx@ = pointer to context to initialize |
| 263 | * |
| 264 | * Returns: --- |
| 265 | * |
| 266 | * Use: Initializes a SHAKE context. The context is initially in |
| 267 | * the `absorbing' state: feed it data with @shake_hash@. |
| 268 | */ |
| 269 | |
| 270 | void shake128_init(shake_ctx *ctx) { init_shake(ctx, 128, 0, 0, 0, 0); } |
| 271 | void shake256_init(shake_ctx *ctx) { init_shake(ctx, 256, 0, 0, 0, 0); } |
| 272 | |
| 273 | /* --- @shake_hash@ --- * |
| 274 | * |
| 275 | * Arguments: @shake_ctx *ctx@ = context to update |
| 276 | * @const void *p@ = input buffer |
| 277 | * @size_t sz@ = size of input |
| 278 | * |
| 279 | * Returns: --- |
| 280 | * |
| 281 | * Use: Feeds input data into a SHAKE context. The context must be |
| 282 | * in `absorbing' state. |
| 283 | */ |
| 284 | |
| 285 | void shake_hash(shake_ctx *ctx, const void *p, size_t sz) |
| 286 | { assert(ctx->st == ST_ABSORB); sha3_hash(&ctx->h, p, sz); } |
| 287 | |
| 288 | /* --- @shake_xof@ --- * |
| 289 | * |
| 290 | * Arguments: @shake_ctx *ctx@ = context to update |
| 291 | * |
| 292 | * Returns: --- |
| 293 | * |
| 294 | * Use: Switches the context into `squeezing' state. Use @shake_get@ |
| 295 | * or @shake_mask@ to extract data. |
| 296 | */ |
| 297 | |
| 298 | void shake_xof(shake_ctx *ctx) |
| 299 | { |
| 300 | assert(ctx->st == ST_ABSORB); |
| 301 | pad(&ctx->h, ctx->op, 0x80); |
| 302 | ctx->st = ST_SQUEEZE; |
| 303 | ctx->h.n = ctx->h.r; |
| 304 | } |
| 305 | |
| 306 | /* --- @shake_get@ --- * |
| 307 | * |
| 308 | * Arguments: @shake_ctx *ctx@ = context to update |
| 309 | * @void *p@ = output buffer |
| 310 | * @size_t sz@ = size of output |
| 311 | * |
| 312 | * Returns: --- |
| 313 | * |
| 314 | * Use: Extracts output from a SHAKE context. The context must be |
| 315 | * in `squeezing' state. |
| 316 | */ |
| 317 | |
| 318 | void shake_get(shake_ctx *ctx, void *p, size_t sz) |
| 319 | { |
| 320 | octet *q = p; |
| 321 | size_t left = ctx->h.r - ctx->h.n; |
| 322 | |
| 323 | assert(ctx->st == ST_SQUEEZE); |
| 324 | if (left >= sz) { |
| 325 | memcpy(q, ctx->h.buf + ctx->h.n, sz); |
| 326 | ctx->h.n += sz; |
| 327 | return; |
| 328 | } |
| 329 | if (left) { |
| 330 | memcpy(q, ctx->h.buf + ctx->h.n, left); |
| 331 | q += left; sz -= left; |
| 332 | } |
| 333 | while (sz >= ctx->h.r) { |
| 334 | step(&ctx->h); |
| 335 | squeeze(&ctx->h, q, ctx->h.r/8); |
| 336 | q += ctx->h.r; sz -= ctx->h.r; |
| 337 | } |
| 338 | if (!sz) |
| 339 | ctx->h.n = ctx->h.r; |
| 340 | else { |
| 341 | step(&ctx->h); |
| 342 | squeeze(&ctx->h, ctx->h.buf, ctx->h.r/8); |
| 343 | memcpy(q, ctx->h.buf, sz); |
| 344 | ctx->h.n = sz; |
| 345 | } |
| 346 | } |
| 347 | |
| 348 | /* --- @shake_done@ --- * |
| 349 | * |
| 350 | * Arguments: @shake_ctx *ctx@ = context to update |
| 351 | * @void *h@ = where to write the hash |
| 352 | * @size_t hsz@ = size of the hash to make |
| 353 | * |
| 354 | * Returns: --- |
| 355 | * |
| 356 | * Use: Switches the context into `squeezing' state. Use @shake_get@ |
| 357 | * or @shake_mask@ to extract data. |
| 358 | */ |
| 359 | |
| 360 | void shake_done(shake_ctx *ctx, void *h, size_t hsz) |
| 361 | { shake_xof(ctx); shake_get(ctx, h, hsz); ctx->st = ST_DEAD; } |
| 362 | |
| 363 | /*----- That's all, folks -------------------------------------------------*/ |