| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Common features for DES implementation |
| 4 | * |
| 5 | * (c) 1999 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of Catacomb. |
| 11 | * |
| 12 | * Catacomb is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU Library General Public License as |
| 14 | * published by the Free Software Foundation; either version 2 of the |
| 15 | * License, or (at your option) any later version. |
| 16 | * |
| 17 | * Catacomb is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU Library General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU Library General Public |
| 23 | * License along with Catacomb; if not, write to the Free |
| 24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 25 | * MA 02111-1307, USA. |
| 26 | */ |
| 27 | |
| 28 | #ifndef CATACOMB_DES_BASE_H |
| 29 | #define CATACOMB_DES_BASE_H |
| 30 | |
| 31 | #ifdef __cplusplus |
| 32 | extern "C" { |
| 33 | #endif |
| 34 | |
| 35 | /*----- Header files ------------------------------------------------------*/ |
| 36 | |
| 37 | #include <mLib/bits.h> |
| 38 | |
| 39 | #ifndef CATACOMB_PERMUTE_H |
| 40 | # include "permute.h" |
| 41 | #endif |
| 42 | |
| 43 | /*----- External data -----------------------------------------------------*/ |
| 44 | |
| 45 | extern const uint32 des_sp[8][64]; |
| 46 | |
| 47 | /*----- Macros ------------------------------------------------------------*/ |
| 48 | |
| 49 | /* --- @DES_ROUND@ --- * |
| 50 | * |
| 51 | * This is the basic DES round function. The inputs are the two subkey |
| 52 | * halves, and the left and right block halves. Note that the block halves |
| 53 | * are rotated left one place at this point. This wraps what's meant to be |
| 54 | * the top bit around to the bottom, so I get a clear run at the S-boxes. |
| 55 | */ |
| 56 | |
| 57 | #define DES_ROUND(ka, kb, x, y) do { \ |
| 58 | uint32 _t = (y) ^ (ka); \ |
| 59 | (x) ^= des_sp[7][(_t >> 0) & 0x3f] ^ \ |
| 60 | des_sp[5][(_t >> 8) & 0x3f] ^ \ |
| 61 | des_sp[3][(_t >> 16) & 0x3f] ^ \ |
| 62 | des_sp[1][(_t >> 24) & 0x3f]; \ |
| 63 | _t = ROR32((y), 4) ^ (kb); \ |
| 64 | (x) ^= des_sp[6][(_t >> 0) & 0x3f] ^ \ |
| 65 | des_sp[4][(_t >> 8) & 0x3f] ^ \ |
| 66 | des_sp[2][(_t >> 16) & 0x3f] ^ \ |
| 67 | des_sp[0][(_t >> 24) & 0x3f]; \ |
| 68 | } while (0) |
| 69 | |
| 70 | /* --- @DES_IP@, @DES_IPINV@ --- * |
| 71 | * |
| 72 | * The cryptographically useless initial and final permutations. The initial |
| 73 | * permutation also rotates the two block halves left by one place. This is |
| 74 | * undone by the inverse permutation at the end. |
| 75 | * |
| 76 | * The initial permutation is traditionally given by the table |
| 77 | * |
| 78 | * 58 50 42 34 26 18 10 2 |
| 79 | * 60 52 44 36 28 20 12 4 |
| 80 | * 62 54 46 38 30 22 14 6 |
| 81 | * 64 56 48 40 32 24 16 8 |
| 82 | * 57 49 41 33 25 17 9 1 |
| 83 | * 59 51 43 35 27 19 11 3 |
| 84 | * 61 53 45 37 29 21 13 5 |
| 85 | * 63 55 47 39 31 23 15 7 |
| 86 | * |
| 87 | * The bit numbering is terrible. If the two halves are X and Y, then the |
| 88 | * numbering starts with the most significant bit of X, which is bit 1, |
| 89 | * working down towards the least significant bit, and then continuing with |
| 90 | * the bits of Y, again in order of decreasing significance. The table |
| 91 | * entries are in this same order, indicating that `bit 1' of the output is |
| 92 | * `bit 58' of the input and so on. |
| 93 | * |
| 94 | * I opt instead to number the bits starting from the least significant bit |
| 95 | * of Y, which is bit 0, up to the most significant bit of X, which is |
| 96 | * bit 63. This means that we need to reverse the table (because we're going |
| 97 | * to read it in the other direction) and subtract each entry from 64 (to |
| 98 | * correct the bit numbering). The resulting table is |
| 99 | * |
| 100 | * 57 49 41 33 25 17 9 1 |
| 101 | * 59 51 43 35 27 19 11 3 |
| 102 | * 61 53 45 37 29 21 13 5 |
| 103 | * 63 55 47 39 31 23 15 7 |
| 104 | * 56 48 40 32 24 16 8 0 |
| 105 | * 58 50 42 34 26 18 10 2 |
| 106 | * 60 52 44 36 28 20 12 4 |
| 107 | * 62 54 46 38 30 22 14 6 |
| 108 | * |
| 109 | * which, interestingly, is /also/ what you get if you just subtract one from |
| 110 | * each of the original table's entries. |
| 111 | * |
| 112 | * If we look at this table in binary, the patterns are much clearer. |
| 113 | * |
| 114 | * 111001 110001 101001 100001 011001 010001 001001 000001 |
| 115 | * 111011 110011 101011 100011 011011 010011 001011 000011 |
| 116 | * 111101 110101 101101 100101 011101 010101 001101 000101 |
| 117 | * 111111 110111 101111 100111 011111 010111 001111 000111 |
| 118 | * 111000 110000 101000 100000 011000 010000 001000 000000 |
| 119 | * 111010 110010 101010 100010 011010 010010 001010 000010 |
| 120 | * 111100 110100 101100 100100 011100 010100 001100 000100 |
| 121 | * 111110 110110 101110 100110 011110 010110 001110 000110 |
| 122 | * |
| 123 | * We can implement this efficiently using our permutation machinery. |
| 124 | * Writing ~k for index bit @k@ inverted, this permutation reflects the index |
| 125 | * transformation given by ~0, 2, 1, ~5, ~4, ~3. There's a traditional |
| 126 | * swizzle sequence for this, which we used to use, namely: |
| 127 | * |
| 128 | * // 5, 4, 3, 2, 1, 0 |
| 129 | * TWIZZLE_XCPL (x, y, 2); // ~2, 4, 3, ~5, 1, 0 |
| 130 | * SWIZZLE_XCPL2(x, y, 1, 4); // ~2, ~1, 3, ~5, ~4, 0 |
| 131 | * SWIZZLE_XCPL2(x, y, 0, 3); // ~2, ~1, ~0, ~5, ~4, ~3 |
| 132 | * SWIZZLE_XCPL2(x, y, 3, 4); // ~2, 0, 1, ~5, ~4, ~3 |
| 133 | * TWIZZLE_XCPL (x, y, 4); // ~0, 2, 1, ~5, ~4, ~3 |
| 134 | * |
| 135 | * Essentially this is an antitranspose -- a reflection about the |
| 136 | * antidiagonal -- followed by a couple of fixup stages. But the non-twizzle |
| 137 | * steps require more operations, and it's easy to find a sequence which |
| 138 | * always acts on the (current) index bit 5, moving it to where it's wanted, |
| 139 | * and inverting it if necessary, so we only need twizzles. |
| 140 | */ |
| 141 | |
| 142 | #define DES_IP(x, y) do { \ |
| 143 | TWIZZLE_XCPL(x, y, 2); /* ~2, 4, 3, ~5, 1, 0 */ \ |
| 144 | TWIZZLE_XCPL(x, y, 4); /* ~4, 2, 3, ~5, 1, 0 */ \ |
| 145 | TWIZZLE_EXCH(x, y, 1); /* 1, 2, 3, ~5, ~4, 0 */ \ |
| 146 | TWIZZLE_EXCH(x, y, 3); /* 3, 2, 1, ~5, ~4, 0 */ \ |
| 147 | TWIZZLE_XCPL(x, y, 0); /* ~0, 2, 1, ~5, ~4, ~3 */ \ |
| 148 | x = ROL32(x, 1); y = ROL32(y, 1); \ |
| 149 | } while (0) |
| 150 | |
| 151 | #define DES_IPINV(x, y) do { \ |
| 152 | x = ROR32(x, 1); y = ROR32(y, 1); /* ~0, 2, 1, ~5, ~4, ~3 */ \ |
| 153 | TWIZZLE_XCPL(x, y, 0); /* 3, 2, 1, ~5, ~4, 0 */ \ |
| 154 | TWIZZLE_EXCH(x, y, 3); /* 1, 2, 3, ~5, ~4, 0 */ \ |
| 155 | TWIZZLE_EXCH(x, y, 1); /* ~4, 2, 3, ~5, 1, 0 */ \ |
| 156 | TWIZZLE_XCPL(x, y, 4); /* 3, 2, 1, ~5, ~4, 0 */ \ |
| 157 | TWIZZLE_XCPL(x, y, 2); /* 5, 4, 3, 2, 1, 0 */ \ |
| 158 | } while (0) |
| 159 | |
| 160 | /* --- @DES_EBLK@, @DES_DBLK@ --- * |
| 161 | * |
| 162 | * Whole block encryption and decryption. |
| 163 | */ |
| 164 | |
| 165 | #define DES_EBLK(k, a, b, c, d) do { \ |
| 166 | const uint32 *_k = (k); \ |
| 167 | uint32 _x = (a), _y = (b); \ |
| 168 | DES_ROUND(_k[0], _k[1], _x, _y); _k += 2; \ |
| 169 | DES_ROUND(_k[0], _k[1], _y, _x); _k += 2; \ |
| 170 | DES_ROUND(_k[0], _k[1], _x, _y); _k += 2; \ |
| 171 | DES_ROUND(_k[0], _k[1], _y, _x); _k += 2; \ |
| 172 | DES_ROUND(_k[0], _k[1], _x, _y); _k += 2; \ |
| 173 | DES_ROUND(_k[0], _k[1], _y, _x); _k += 2; \ |
| 174 | DES_ROUND(_k[0], _k[1], _x, _y); _k += 2; \ |
| 175 | DES_ROUND(_k[0], _k[1], _y, _x); _k += 2; \ |
| 176 | DES_ROUND(_k[0], _k[1], _x, _y); _k += 2; \ |
| 177 | DES_ROUND(_k[0], _k[1], _y, _x); _k += 2; \ |
| 178 | DES_ROUND(_k[0], _k[1], _x, _y); _k += 2; \ |
| 179 | DES_ROUND(_k[0], _k[1], _y, _x); _k += 2; \ |
| 180 | DES_ROUND(_k[0], _k[1], _x, _y); _k += 2; \ |
| 181 | DES_ROUND(_k[0], _k[1], _y, _x); _k += 2; \ |
| 182 | DES_ROUND(_k[0], _k[1], _x, _y); _k += 2; \ |
| 183 | DES_ROUND(_k[0], _k[1], _y, _x); _k += 2; \ |
| 184 | (c) = _y; \ |
| 185 | (d) = _x; \ |
| 186 | } while (0) |
| 187 | |
| 188 | #define DES_DBLK(k, a, b, c, d) do { \ |
| 189 | const uint32 *_k = (k) + 32; \ |
| 190 | uint32 _x = (a), _y = (b); \ |
| 191 | _k -= 2; DES_ROUND(_k[0], _k[1], _x, _y); \ |
| 192 | _k -= 2; DES_ROUND(_k[0], _k[1], _y, _x); \ |
| 193 | _k -= 2; DES_ROUND(_k[0], _k[1], _x, _y); \ |
| 194 | _k -= 2; DES_ROUND(_k[0], _k[1], _y, _x); \ |
| 195 | _k -= 2; DES_ROUND(_k[0], _k[1], _x, _y); \ |
| 196 | _k -= 2; DES_ROUND(_k[0], _k[1], _y, _x); \ |
| 197 | _k -= 2; DES_ROUND(_k[0], _k[1], _x, _y); \ |
| 198 | _k -= 2; DES_ROUND(_k[0], _k[1], _y, _x); \ |
| 199 | _k -= 2; DES_ROUND(_k[0], _k[1], _x, _y); \ |
| 200 | _k -= 2; DES_ROUND(_k[0], _k[1], _y, _x); \ |
| 201 | _k -= 2; DES_ROUND(_k[0], _k[1], _x, _y); \ |
| 202 | _k -= 2; DES_ROUND(_k[0], _k[1], _y, _x); \ |
| 203 | _k -= 2; DES_ROUND(_k[0], _k[1], _x, _y); \ |
| 204 | _k -= 2; DES_ROUND(_k[0], _k[1], _y, _x); \ |
| 205 | _k -= 2; DES_ROUND(_k[0], _k[1], _x, _y); \ |
| 206 | _k -= 2; DES_ROUND(_k[0], _k[1], _y, _x); \ |
| 207 | (c) = _y; \ |
| 208 | (d) = _x; \ |
| 209 | } while (0) |
| 210 | |
| 211 | /*----- That's all, folks -------------------------------------------------*/ |
| 212 | |
| 213 | #ifdef __cplusplus |
| 214 | } |
| 215 | #endif |
| 216 | |
| 217 | #endif |