| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: safer.c,v 1.2 2004/04/08 01:36:15 mdw Exp $ |
| 4 | * |
| 5 | * The SAFER block cipher |
| 6 | * |
| 7 | * (c) 2001 Straylight/Edgeware |
| 8 | */ |
| 9 | |
| 10 | /*----- Licensing notice --------------------------------------------------* |
| 11 | * |
| 12 | * This file is part of Catacomb. |
| 13 | * |
| 14 | * Catacomb is free software; you can redistribute it and/or modify |
| 15 | * it under the terms of the GNU Library General Public License as |
| 16 | * published by the Free Software Foundation; either version 2 of the |
| 17 | * License, or (at your option) any later version. |
| 18 | * |
| 19 | * Catacomb is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | * GNU Library General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU Library General Public |
| 25 | * License along with Catacomb; if not, write to the Free |
| 26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 27 | * MA 02111-1307, USA. |
| 28 | */ |
| 29 | |
| 30 | /*----- Header files ------------------------------------------------------*/ |
| 31 | |
| 32 | #include <assert.h> |
| 33 | #include <stdio.h> |
| 34 | |
| 35 | #include <mLib/bits.h> |
| 36 | |
| 37 | #include "blkc.h" |
| 38 | #include "gcipher.h" |
| 39 | #include "paranoia.h" |
| 40 | #include "safer.h" |
| 41 | #include "safer-tab.h" |
| 42 | |
| 43 | /*----- Global variables --------------------------------------------------*/ |
| 44 | |
| 45 | const octet safer_keysz[] = { KSZ_SET, 8, 16, 0 }; |
| 46 | |
| 47 | /*----- Important tables --------------------------------------------------*/ |
| 48 | |
| 49 | static const octet s[265] = SAFER_S, si[256] = SAFER_SI; |
| 50 | |
| 51 | /*----- Main code ---------------------------------------------------------*/ |
| 52 | |
| 53 | /* --- @safer_setup@ --- * |
| 54 | * |
| 55 | * Arguments: @safer_ctx *k@ = pointer to context to initialize |
| 56 | * @unsigned r@ = number of rounds wanted |
| 57 | * @unsigned f@ = various other flags |
| 58 | * @const void *buf@ = pointer to key material |
| 59 | * @size_t sz@ = size of key material in bytes |
| 60 | * |
| 61 | * Returns: --- |
| 62 | * |
| 63 | * Use: Initializes an SAFER expanded key. A default number of |
| 64 | * rounds is chosen, based on the key length. |
| 65 | */ |
| 66 | |
| 67 | struct ksched { |
| 68 | unsigned i; |
| 69 | octet x[9]; |
| 70 | }; |
| 71 | |
| 72 | static void init(struct ksched *t, const octet *k) |
| 73 | { |
| 74 | memcpy(t->x, k, 8); |
| 75 | t->i = 1; |
| 76 | } |
| 77 | |
| 78 | static void init_sk(struct ksched *t, const octet *k) |
| 79 | { |
| 80 | unsigned i; |
| 81 | octet x; |
| 82 | memcpy(t->x, k, 8); |
| 83 | for (x = 0, i = 0; i < 8; x ^= k[i++]) |
| 84 | ; |
| 85 | t->x[8] = x; |
| 86 | t->i = 1; |
| 87 | } |
| 88 | |
| 89 | static void next(struct ksched *t, octet *k) |
| 90 | { |
| 91 | unsigned i; |
| 92 | if (k) { |
| 93 | memcpy(k, t->x, 8); |
| 94 | if (t->i > 1) { |
| 95 | for (i = 0; i < 8; i++) |
| 96 | k[i] += s[s[U8(9*t->i + i + 1)]]; |
| 97 | } |
| 98 | } |
| 99 | for (i = 0; i < 8; i++) |
| 100 | t->x[i] = ROL8(t->x[i], 3); |
| 101 | t->i++; |
| 102 | } |
| 103 | |
| 104 | static void next_sk(struct ksched *t, octet *k) |
| 105 | { |
| 106 | unsigned i; |
| 107 | i = (t->i - 1)%9; |
| 108 | if (k) { |
| 109 | if (i < 2) |
| 110 | memcpy(k, t->x + i, 8); |
| 111 | else { |
| 112 | memcpy(k, t->x + i, 9 - i); |
| 113 | memcpy(k + 9 - i, t->x, i - 1); |
| 114 | } |
| 115 | if (t->i > 1) { |
| 116 | for (i = 0; i < 8; i++) |
| 117 | k[i] += s[s[U8(9*t->i + i + 1)]]; |
| 118 | } |
| 119 | } |
| 120 | for (i = 0; i < 9; i++) |
| 121 | t->x[i] = ROL8(t->x[i], 3); |
| 122 | t->i++; |
| 123 | } |
| 124 | |
| 125 | void safer_setup(safer_ctx *k, unsigned r, unsigned f, |
| 126 | const void *buf, size_t sz) |
| 127 | { |
| 128 | struct ksched ka, kb; |
| 129 | void (*in)(struct ksched *, const octet *); |
| 130 | void (*nx)(struct ksched *, octet *); |
| 131 | octet *kk; |
| 132 | |
| 133 | assert(r <= SAFER_MAXROUNDS); |
| 134 | KSZ_ASSERT(safer, sz); |
| 135 | |
| 136 | if (f & SAFER_SK) { |
| 137 | in = init_sk; |
| 138 | nx = next_sk; |
| 139 | } else { |
| 140 | in = init; |
| 141 | nx = next; |
| 142 | } |
| 143 | |
| 144 | in(&kb, buf); |
| 145 | in(&ka, sz == 8 ? buf : (const octet *)buf + 8); |
| 146 | |
| 147 | k->r = r; |
| 148 | kk = k->k; |
| 149 | while (r) { |
| 150 | nx(&ka, kk); nx(&kb, 0); kk += 8; |
| 151 | nx(&kb, kk); nx(&ka, 0); kk += 8; |
| 152 | r--; |
| 153 | } |
| 154 | nx(&ka, kk); kk += 8; |
| 155 | } |
| 156 | |
| 157 | /* --- @safer_init@, @safersk_init@ --- * |
| 158 | * |
| 159 | * Arguments: @safer_ctx *k@ = pointer to context to initialize |
| 160 | * @const void *buf@ = pointer to key material |
| 161 | * @size_t sz@ = size of key material in bytes |
| 162 | * |
| 163 | * Returns: --- |
| 164 | * |
| 165 | * Use: Initializes an SAFER expanded key. A default number of |
| 166 | * rounds is chosen, based on the key length. |
| 167 | */ |
| 168 | |
| 169 | void safer_init(safer_ctx *k, const void *buf, size_t sz) |
| 170 | { |
| 171 | safer_setup(k, sz == 8 ? 6 : 10, 0, buf, sz); |
| 172 | } |
| 173 | |
| 174 | void safersk_init(safer_ctx *k, const void *buf, size_t sz) |
| 175 | { |
| 176 | safer_setup(k, sz == 8 ? 8 : 10, SAFER_SK, buf, sz); |
| 177 | } |
| 178 | |
| 179 | /* --- @safer_eblk@, @safer_dblk@ --- * |
| 180 | * |
| 181 | * Arguments: @const safer_ctx *k@ = pointer to SAFER context |
| 182 | * @const uint32 s[2]@ = pointer to source block |
| 183 | * @const uint32 d[2]@ = pointer to destination block |
| 184 | * |
| 185 | * Returns: --- |
| 186 | * |
| 187 | * Use: Low-level block encryption and decryption. |
| 188 | */ |
| 189 | |
| 190 | #define UNPACK(src, a, b, c, d, e, f, g, h) do { \ |
| 191 | a = U8(src[0] >> 24); b = U8(src[0] >> 16); \ |
| 192 | c = U8(src[0] >> 8); d = U8(src[0] >> 0); \ |
| 193 | e = U8(src[1] >> 24); f = U8(src[1] >> 16); \ |
| 194 | g = U8(src[1] >> 8); h = U8(src[1] >> 0); \ |
| 195 | } while (0) |
| 196 | |
| 197 | #define PACK(dst, a, b, c, d, e, f, g, h) do { \ |
| 198 | dst[0] = (U8(a) << 24) | (U8(b) << 16) | (U8(c) << 8) | U8(d); \ |
| 199 | dst[1] = (U8(e) << 24) | (U8(f) << 16) | (U8(g) << 8) | U8(h); \ |
| 200 | } while (0) |
| 201 | |
| 202 | #define F(x, y) y += x, x += y |
| 203 | #define G(x, y) x -= y, y -= x |
| 204 | |
| 205 | #define PHT(a, b, c, d, e, f, g, h) do { \ |
| 206 | F(a, b); F(c, d); F(e, f); F(g, h); \ |
| 207 | F(a, c); F(e, g); F(b, d); F(f, h); \ |
| 208 | F(a, e); F(b, f); F(c, g); F(d, h); \ |
| 209 | } while (0) |
| 210 | #define IPHT(a, b, c, d, e, f, g, h) do { \ |
| 211 | G(a, e); G(b, f); G(c, g); G(d, h); \ |
| 212 | G(a, c); G(e, g); G(b, d); G(f, h); \ |
| 213 | G(a, b); G(c, d); G(e, f); G(g, h); \ |
| 214 | } while (0) |
| 215 | |
| 216 | #define KXA(k, a, b, c, d, e, f, g, h) do { \ |
| 217 | a ^= *k++; b += *k++; c += *k++; d ^= *k++; \ |
| 218 | e ^= *k++; f += *k++; g += *k++; h ^= *k++; \ |
| 219 | } while (0) |
| 220 | #define SUB(a, b, c, d, e, f, g, h) do { \ |
| 221 | a = s[U8(a)]; b = si[U8(b)]; c = si[U8(c)]; d = s[U8(d)]; \ |
| 222 | e = s[U8(e)]; f = si[U8(f)]; g = si[U8(g)]; h = s[U8(h)]; \ |
| 223 | } while (0) |
| 224 | #define KAX(k, a, b, c, d, e, f, g, h) do { \ |
| 225 | a += *k++; b ^= *k++; c ^= *k++; d += *k++; \ |
| 226 | e += *k++; f ^= *k++; g ^= *k++; h += *k++; \ |
| 227 | } while (0) |
| 228 | |
| 229 | #define KXS(k, a, b, c, d, e, f, g, h) do { \ |
| 230 | h ^= *--k; g -= *--k; f -= *--k; e ^= *--k; \ |
| 231 | d ^= *--k; c -= *--k; b -= *--k; a ^= *--k; \ |
| 232 | } while (0) |
| 233 | #define ISUB(a, b, c, d, e, f, g, h) do { \ |
| 234 | a = si[U8(a)]; b = s[U8(b)]; c = s[U8(c)]; d = si[U8(d)]; \ |
| 235 | e = si[U8(e)]; f = s[U8(f)]; g = s[U8(g)]; h = si[U8(h)]; \ |
| 236 | } while (0) |
| 237 | #define KSX(k, a, b, c, d, e, f, g, h) do { \ |
| 238 | h -= *--k; g ^= *--k; f ^= *--k; e -= *--k; \ |
| 239 | d -= *--k; c ^= *--k; b ^= *--k; a -= *--k; \ |
| 240 | } while (0) |
| 241 | |
| 242 | #define EROUND(k, a, b, c, d, e, f, g, h) do { \ |
| 243 | KXA(k, a, b, c, d, e, f, g, h); \ |
| 244 | SUB(a, b, c, d, e, f, g, h); \ |
| 245 | KAX(k, a, b, c, d, e, f, g, h); \ |
| 246 | PHT(a, b, c, d, e, f, g, h); \ |
| 247 | } while (0) |
| 248 | |
| 249 | #define DROUND(k, a, b, c, d, e, f, g, h) do { \ |
| 250 | IPHT(a, b, c, d, e, f, g, h); \ |
| 251 | KSX(k, a, b, c, d, e, f, g, h); \ |
| 252 | ISUB(a, b, c, d, e, f, g, h); \ |
| 253 | KXS(k, a, b, c, d, e, f, g, h); \ |
| 254 | } while (0) |
| 255 | |
| 256 | |
| 257 | void safer_eblk(const safer_ctx *k, const uint32 *src, uint32 *dst) |
| 258 | { |
| 259 | octet a, b, c, d, e, f, g, h; |
| 260 | unsigned r = k->r; |
| 261 | const octet *kk = k->k; |
| 262 | |
| 263 | UNPACK(src, a, b, c, d, e, f, g, h); |
| 264 | while (r >= 3) { |
| 265 | EROUND(kk, a, b, c, d, e, f, g, h); |
| 266 | EROUND(kk, a, e, b, f, c, g, d, h); |
| 267 | EROUND(kk, a, c, e, g, b, d, f, h); |
| 268 | r -= 3; |
| 269 | } |
| 270 | switch (r) { |
| 271 | case 0: |
| 272 | KXA(kk, a, b, c, d, e, f, g, h); |
| 273 | PACK(dst, a, b, c, d, e, f, g ,h); |
| 274 | break; |
| 275 | case 1: |
| 276 | EROUND(kk, a, b, c, d, e, f, g, h); |
| 277 | KXA(kk, a, e, b, f, c, g, d, h); |
| 278 | PACK(dst, a, e, b, f, c, g, d, h); |
| 279 | break; |
| 280 | case 2: |
| 281 | EROUND(kk, a, b, c, d, e, f, g, h); |
| 282 | EROUND(kk, a, e, b, f, c, g, d, h); |
| 283 | KXA(kk, a, c, e, g, b, d, f, h); |
| 284 | PACK(dst, a, c, e, g, b, d, f, h); |
| 285 | break; |
| 286 | } |
| 287 | } |
| 288 | |
| 289 | void safer_dblk(const safer_ctx *k, const uint32 *src, uint32 *dst) |
| 290 | { |
| 291 | octet a, b, c, d, e, f, g, h; |
| 292 | unsigned r = k->r; |
| 293 | const octet *kk = k->k + 16 * r + 8; |
| 294 | switch (r%3) { |
| 295 | default: |
| 296 | case 0: |
| 297 | UNPACK(src, a, b, c, d, e, f, g, h); |
| 298 | KXS(kk, a, b, c, d, e, f, g, h); |
| 299 | break; |
| 300 | case 1: |
| 301 | UNPACK(src, a, e, b, f, c, g, d, h); |
| 302 | KXS(kk, a, e, b, f, c, g, d, h); |
| 303 | r--; |
| 304 | goto one_round; |
| 305 | case 2: |
| 306 | UNPACK(src, a, c, e, g, b, d, f, h); |
| 307 | KXS(kk, a, c, e, g, b, d, f, h); |
| 308 | r -= 2; |
| 309 | DROUND(kk, a, e, b, f, c, g, d, h); |
| 310 | one_round: |
| 311 | DROUND(kk, a, b, c, d, e, f, g, h); |
| 312 | break; |
| 313 | } |
| 314 | while (r) { |
| 315 | DROUND(kk, a, c, e, g, b, d, f, h); |
| 316 | DROUND(kk, a, e, b, f, c, g, d, h); |
| 317 | DROUND(kk, a, b, c, d, e, f, g, h); |
| 318 | r -= 3; |
| 319 | } |
| 320 | PACK(dst, a, b, c, d, e, f, g, h); |
| 321 | } |
| 322 | |
| 323 | BLKC_TEST(SAFER, safer) |
| 324 | |
| 325 | /*----- That's all, folks -------------------------------------------------*/ |