| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: serpent.c,v 1.1 2000/06/17 12:08:43 mdw Exp $ |
| 4 | * |
| 5 | * The Serpent block cipher |
| 6 | * |
| 7 | * (c) 2000 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 | /*----- Revision history --------------------------------------------------* |
| 31 | * |
| 32 | * $Log: serpent.c,v $ |
| 33 | * Revision 1.1 2000/06/17 12:08:43 mdw |
| 34 | * New cipher. |
| 35 | * |
| 36 | */ |
| 37 | |
| 38 | /*----- Header files ------------------------------------------------------*/ |
| 39 | |
| 40 | #include <assert.h> |
| 41 | #include <stdio.h> |
| 42 | |
| 43 | #include <mLib/bits.h> |
| 44 | |
| 45 | #include "blkc.h" |
| 46 | #include "gcipher.h" |
| 47 | #include "serpent.h" |
| 48 | #include "serpent-sbox.h" |
| 49 | |
| 50 | /*----- Global variables --------------------------------------------------*/ |
| 51 | |
| 52 | const octet serpent_keysz[] = { KSZ_RANGE, SERPENT_KEYSZ, 0, 32, 1 }; |
| 53 | |
| 54 | /*----- Main code ---------------------------------------------------------*/ |
| 55 | |
| 56 | /* --- @serpent_init@ --- * |
| 57 | * |
| 58 | * Arguments: @serpent_ctx *k@ = pointer to context block to initialize |
| 59 | * @const void *buf@ = pointer to input buffer |
| 60 | * @size_t sz@ = size of input buffer |
| 61 | * |
| 62 | * Returns: --- |
| 63 | * |
| 64 | * Use: Initializes a Serpent context. The key may be any length of |
| 65 | * up to 32 bytes (256 bits). |
| 66 | */ |
| 67 | |
| 68 | void serpent_init(serpent_ctx *k, const void *buf, size_t sz) |
| 69 | { |
| 70 | uint32 a; |
| 71 | unsigned b; |
| 72 | const octet *p, *q; |
| 73 | size_t i; |
| 74 | uint32 pk[8 + 132]; |
| 75 | |
| 76 | KSZ_ASSERT(serpent, sz); |
| 77 | |
| 78 | /* --- Read the key into the buffer --- */ |
| 79 | |
| 80 | if (sz > 32) |
| 81 | sz = 32; |
| 82 | i = 0; p = buf; q = p + sz; |
| 83 | a = 0; b = 0; |
| 84 | while (p < q) { |
| 85 | a |= (uint32)*p++ << b; |
| 86 | b += 8; |
| 87 | if (b == 32) { |
| 88 | pk[i++] = a; |
| 89 | a = 0; b = 0; |
| 90 | } |
| 91 | } |
| 92 | |
| 93 | /* --- Pad short keys --- */ |
| 94 | |
| 95 | if (i < 8) { |
| 96 | a |= 0x01 << b; |
| 97 | b += 8; |
| 98 | pk[i++] = a; |
| 99 | for (; i < 8; i++) |
| 100 | pk[i] = 0; |
| 101 | } |
| 102 | |
| 103 | /* --- Expand the prekeys to fill the buffer --- */ |
| 104 | |
| 105 | for (i = 8; i < 8 + 132; i++) { |
| 106 | uint32 x = (pk[i - 8] ^ pk[i - 5] ^ pk[i - 3] ^ pk[i - 1] ^ |
| 107 | (i - 8) ^ 0x9e3779b9); |
| 108 | k->k[i - 8] = pk[i] = ROL32(x, 11); |
| 109 | } |
| 110 | |
| 111 | /* --- Now substitute everything --- */ |
| 112 | |
| 113 | i = 0; |
| 114 | goto midway; |
| 115 | while (i < 132) { |
| 116 | #define KSUB(r) do { \ |
| 117 | uint32 a, b, c, d; \ |
| 118 | a = k->k[i]; b = k->k[i + 1]; c = k->k[i + 2]; d = k->k[i + 3]; \ |
| 119 | S##r(a, b, c, d); \ |
| 120 | k->k[i] = a; k->k[i + 1] = b; k->k[i + 2] = c; k->k[i + 3] = d; \ |
| 121 | i += 4; \ |
| 122 | } while (0) |
| 123 | KSUB(2); KSUB(1); KSUB(0); KSUB(7); |
| 124 | KSUB(6); KSUB(5); KSUB(4); |
| 125 | midway: |
| 126 | KSUB(3); |
| 127 | #undef KSUB |
| 128 | } |
| 129 | } |
| 130 | |
| 131 | /* --- @serpent_eblk@, @serpent_dblk@ --- * |
| 132 | * |
| 133 | * Arguments: @const serpent_ctx *k@ = pointer to key context |
| 134 | * @const uint32 s[4]@ = pointer to source block |
| 135 | * @uint32 d[4]@ = pointer to destination block |
| 136 | * |
| 137 | * Returns: --- |
| 138 | * |
| 139 | * Use: Low-level block encryption. |
| 140 | */ |
| 141 | |
| 142 | #define EROUND(a, b, c, d, r, k) do { \ |
| 143 | a ^= *k++; b ^= *k++; c ^= *k++; d ^= *k++; \ |
| 144 | S##r(a, b, c, d); \ |
| 145 | a = ROL32(a, 13); c = ROL32(c, 3); b ^= a ^ c; d ^= c ^ (a << 3); \ |
| 146 | b = ROL32(b, 1); d = ROL32(d, 7); a ^= b ^ d; c ^= d ^ (b << 7); \ |
| 147 | a = ROL32(a, 5); c = ROL32(c, 22); \ |
| 148 | } while (0) |
| 149 | |
| 150 | #define DROUND(a, b, c, d, r, k) do { \ |
| 151 | IS##r(a, b, c, d); \ |
| 152 | d ^= *--k; c ^= *--k; b ^= *--k; a ^= *--k; \ |
| 153 | a = ROR32(a, 5); c = ROR32(c, 22); a ^= b ^ d; c ^= d ^ (b << 7); \ |
| 154 | b = ROR32(b, 1); d = ROR32(d, 7); b ^= a ^ c; d ^= c ^ (a << 3); \ |
| 155 | a = ROR32(a, 13); c = ROR32(c, 3); \ |
| 156 | } while (0) |
| 157 | |
| 158 | void serpent_eblk(const serpent_ctx *k, const uint32 *s, uint32 *d) |
| 159 | { |
| 160 | uint32 aa = s[0], bb = s[1], cc = s[2], dd = s[3]; |
| 161 | const uint32 *kk = k->k; |
| 162 | |
| 163 | EROUND(aa, bb, cc, dd, 0, kk); EROUND(aa, bb, cc, dd, 1, kk); |
| 164 | EROUND(aa, bb, cc, dd, 2, kk); EROUND(aa, bb, cc, dd, 3, kk); |
| 165 | EROUND(aa, bb, cc, dd, 4, kk); EROUND(aa, bb, cc, dd, 5, kk); |
| 166 | EROUND(aa, bb, cc, dd, 6, kk); EROUND(aa, bb, cc, dd, 7, kk); |
| 167 | |
| 168 | EROUND(aa, bb, cc, dd, 0, kk); EROUND(aa, bb, cc, dd, 1, kk); |
| 169 | EROUND(aa, bb, cc, dd, 2, kk); EROUND(aa, bb, cc, dd, 3, kk); |
| 170 | EROUND(aa, bb, cc, dd, 4, kk); EROUND(aa, bb, cc, dd, 5, kk); |
| 171 | EROUND(aa, bb, cc, dd, 6, kk); EROUND(aa, bb, cc, dd, 7, kk); |
| 172 | |
| 173 | EROUND(aa, bb, cc, dd, 0, kk); EROUND(aa, bb, cc, dd, 1, kk); |
| 174 | EROUND(aa, bb, cc, dd, 2, kk); EROUND(aa, bb, cc, dd, 3, kk); |
| 175 | EROUND(aa, bb, cc, dd, 4, kk); EROUND(aa, bb, cc, dd, 5, kk); |
| 176 | EROUND(aa, bb, cc, dd, 6, kk); EROUND(aa, bb, cc, dd, 7, kk); |
| 177 | |
| 178 | EROUND(aa, bb, cc, dd, 0, kk); EROUND(aa, bb, cc, dd, 1, kk); |
| 179 | EROUND(aa, bb, cc, dd, 2, kk); EROUND(aa, bb, cc, dd, 3, kk); |
| 180 | EROUND(aa, bb, cc, dd, 4, kk); EROUND(aa, bb, cc, dd, 5, kk); |
| 181 | EROUND(aa, bb, cc, dd, 6, kk); |
| 182 | |
| 183 | aa ^= *kk++; bb ^= *kk++; cc ^= *kk++; dd ^= *kk++; |
| 184 | S7(aa, bb, cc, dd); |
| 185 | aa ^= *kk++; bb ^= *kk++; cc ^= *kk++; dd ^= *kk++; |
| 186 | d[0] = aa; d[1] = bb; d[2] = cc; d[3] = dd; |
| 187 | } |
| 188 | |
| 189 | void serpent_dblk(const serpent_ctx *k, const uint32 *s, uint32 *d) |
| 190 | { |
| 191 | uint32 aa = s[0], bb = s[1], cc = s[2], dd = s[3]; |
| 192 | const uint32 *kk = k->k + 132; |
| 193 | |
| 194 | dd ^= *--kk; cc ^= *--kk; bb ^= *--kk; aa ^= *--kk; |
| 195 | |
| 196 | DROUND(aa, bb, cc, dd, 7, kk); DROUND(aa, bb, cc, dd, 6, kk); |
| 197 | DROUND(aa, bb, cc, dd, 5, kk); DROUND(aa, bb, cc, dd, 4, kk); |
| 198 | DROUND(aa, bb, cc, dd, 3, kk); DROUND(aa, bb, cc, dd, 2, kk); |
| 199 | DROUND(aa, bb, cc, dd, 1, kk); DROUND(aa, bb, cc, dd, 0, kk); |
| 200 | |
| 201 | DROUND(aa, bb, cc, dd, 7, kk); DROUND(aa, bb, cc, dd, 6, kk); |
| 202 | DROUND(aa, bb, cc, dd, 5, kk); DROUND(aa, bb, cc, dd, 4, kk); |
| 203 | DROUND(aa, bb, cc, dd, 3, kk); DROUND(aa, bb, cc, dd, 2, kk); |
| 204 | DROUND(aa, bb, cc, dd, 1, kk); DROUND(aa, bb, cc, dd, 0, kk); |
| 205 | |
| 206 | DROUND(aa, bb, cc, dd, 7, kk); DROUND(aa, bb, cc, dd, 6, kk); |
| 207 | DROUND(aa, bb, cc, dd, 5, kk); DROUND(aa, bb, cc, dd, 4, kk); |
| 208 | DROUND(aa, bb, cc, dd, 3, kk); DROUND(aa, bb, cc, dd, 2, kk); |
| 209 | DROUND(aa, bb, cc, dd, 1, kk); DROUND(aa, bb, cc, dd, 0, kk); |
| 210 | |
| 211 | DROUND(aa, bb, cc, dd, 7, kk); DROUND(aa, bb, cc, dd, 6, kk); |
| 212 | DROUND(aa, bb, cc, dd, 5, kk); DROUND(aa, bb, cc, dd, 4, kk); |
| 213 | DROUND(aa, bb, cc, dd, 3, kk); DROUND(aa, bb, cc, dd, 2, kk); |
| 214 | DROUND(aa, bb, cc, dd, 1, kk); |
| 215 | |
| 216 | IS0(aa, bb, cc, dd); |
| 217 | dd ^= *--kk; cc ^= *--kk; bb ^= *--kk; aa ^= *--kk; |
| 218 | d[0] = aa; d[1] = bb; d[2] = cc; d[3] = dd; |
| 219 | } |
| 220 | |
| 221 | BLKC_TEST(SERPENT, serpent) |
| 222 | |
| 223 | /*----- That's all, folks -------------------------------------------------*/ |