| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: desx.c,v 1.1 2001/04/03 19:36:50 mdw Exp $ |
| 4 | * |
| 5 | * Implementation of DESX |
| 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 | /*----- Revision history --------------------------------------------------* |
| 31 | * |
| 32 | * $Log: desx.c,v $ |
| 33 | * Revision 1.1 2001/04/03 19:36:50 mdw |
| 34 | * New block cipher DESX added. |
| 35 | * |
| 36 | */ |
| 37 | |
| 38 | /*----- Header files ------------------------------------------------------*/ |
| 39 | |
| 40 | #include <assert.h> |
| 41 | #include <stdio.h> |
| 42 | #include <stdlib.h> |
| 43 | #include <string.h> |
| 44 | |
| 45 | #include <mLib/bits.h> |
| 46 | |
| 47 | #include "blkc.h" |
| 48 | #include "des-base.h" |
| 49 | #include "des.h" |
| 50 | #include "desx.h" |
| 51 | #include "desx-tab.h" |
| 52 | #include "gcipher.h" |
| 53 | |
| 54 | /*----- Tables ------------------------------------------------------------*/ |
| 55 | |
| 56 | static octet s[256] = DESX_S; |
| 57 | |
| 58 | /*----- Global variables --------------------------------------------------*/ |
| 59 | |
| 60 | const octet desx_keysz[] = { KSZ_SET, 7, 8, 15, 16, 23, 24, 0 }; |
| 61 | |
| 62 | /*----- Main code ---------------------------------------------------------*/ |
| 63 | |
| 64 | /* --- @desx_init@ --- * |
| 65 | * |
| 66 | * Arguments: @desx_ctx *k@ = pointer to key block |
| 67 | * @const void *buf@ = pointer to key buffer |
| 68 | * @size_t sz@ = size of key material |
| 69 | * |
| 70 | * Returns: --- |
| 71 | * |
| 72 | * Use: Initializes a DESX key buffer. The key buffer contains, in |
| 73 | * order, a single-DES key (either 7 or 8 bytes), an optional |
| 74 | * 8-byte pre-whitening key, and an optional 8-byte |
| 75 | * port-whitening key. If no whitening keys are specified, the |
| 76 | * algorithm becomes the same as single-DES. |
| 77 | */ |
| 78 | |
| 79 | static void mangle(octet *b, const octet *p) |
| 80 | { |
| 81 | unsigned i; |
| 82 | |
| 83 | for (i = 0; i < 8; i++) |
| 84 | b[i] = *p++ ^ s[b[i] ^ b[(i + 1) & 7u]]; |
| 85 | } |
| 86 | |
| 87 | void desx_init(desx_ctx *k, const void *buf, size_t sz) |
| 88 | { |
| 89 | const octet *p = buf, *kk = buf; |
| 90 | size_t n; |
| 91 | |
| 92 | KSZ_ASSERT(desx, sz); |
| 93 | |
| 94 | n = sz % 8 == 7 ? 7 : 8; |
| 95 | des_init(&k->k, p, n); |
| 96 | p += n; |
| 97 | sz -= n; |
| 98 | if (!sz) |
| 99 | k->prea = k->preb = k->posta = k->postb = 0; |
| 100 | else { |
| 101 | const octet *q = p; |
| 102 | k->prea = LOAD32(q + 0); |
| 103 | k->preb = LOAD32(q + 4); |
| 104 | p += 8; |
| 105 | sz -= 8; |
| 106 | if (sz) { |
| 107 | k->posta = LOAD32(p + 0); |
| 108 | k->postb = LOAD32(p + 4); |
| 109 | } else { |
| 110 | octet b[16]; |
| 111 | |
| 112 | if (n == 7) { |
| 113 | |
| 114 | /* --- Expand 7 bits to 8 bits --- * |
| 115 | * |
| 116 | * Cloned and hacked from @des_init@ to set parity. |
| 117 | */ |
| 118 | |
| 119 | uint32 x, y, z; |
| 120 | x = LOAD32(kk + 0); |
| 121 | x = (x & 0xfe000000) | ((x & 0x01fffff0) >> 1); |
| 122 | x = (x & 0xfffe0000) | ((x & 0x0001fff8) >> 1); |
| 123 | x = (x & 0xfffffe00) | ((x & 0x000001fc) >> 1); |
| 124 | z = x; z ^= z >> 4; z ^= z >> 2; z ^= z >> 1; |
| 125 | x |= (z & 0x01010101) ^ 0x01010101; |
| 126 | |
| 127 | y = LOAD32(kk + 3) << 1; |
| 128 | y = (y & 0x000000fe) | ((y & 0x1fffff00) << 1); |
| 129 | y = (y & 0x0000fefe) | ((y & 0x3fff0000) << 1); |
| 130 | y = (y & 0x00fefefe) | ((y & 0x7f000000) << 1); |
| 131 | z = y; z ^= z >> 4; z ^= z >> 2; z ^= z >> 1; |
| 132 | y |= (z & 0x01010101) ^ 0x01010101; |
| 133 | |
| 134 | kk = b + 8; |
| 135 | STORE32(kk + 0, x); STORE32(kk + 4, y); |
| 136 | } |
| 137 | |
| 138 | memset(b, 0, 8); |
| 139 | mangle(b, kk); |
| 140 | mangle(b, q); |
| 141 | k->posta = LOAD32(b + 0); |
| 142 | k->postb = LOAD32(b + 4); |
| 143 | } |
| 144 | } |
| 145 | } |
| 146 | |
| 147 | /* --- @desx_eblk@, @desx_dblk@ --- * |
| 148 | * |
| 149 | * Arguments: @const desx_ctx *k@ = pointer to key block |
| 150 | * @const uint32 s[2]@ = pointer to source block |
| 151 | * @uint32 d[2]@ = pointer to destination block |
| 152 | * |
| 153 | * Returns: --- |
| 154 | * |
| 155 | * Use: Low-level block encryption and decryption. |
| 156 | */ |
| 157 | |
| 158 | void desx_eblk(const desx_ctx *k, const uint32 *s, uint32 *d) |
| 159 | { |
| 160 | uint32 x = s[0], y = s[1]; |
| 161 | x ^= k->prea; y ^= k->preb; |
| 162 | DES_IP(x, y); |
| 163 | DES_EBLK(k->k.k, x, y, x, y); |
| 164 | DES_IPINV(x, y); |
| 165 | x ^= k->posta; y ^= k->postb; |
| 166 | d[0] = x, d[1] = y; |
| 167 | } |
| 168 | |
| 169 | void desx_dblk(const desx_ctx *k, const uint32 *s, uint32 *d) |
| 170 | { |
| 171 | uint32 x = s[0], y = s[1]; |
| 172 | x ^= k->posta; y ^= k->postb; |
| 173 | DES_IP(x, y); |
| 174 | DES_DBLK(k->k.k, x, y, x, y); |
| 175 | DES_IPINV(x, y); |
| 176 | x ^= k->prea; y ^= k->preb; |
| 177 | d[0] = x, d[1] = y; |
| 178 | } |
| 179 | |
| 180 | BLKC_TEST(DESX, desx) |
| 181 | |
| 182 | /*----- That's all, folks -------------------------------------------------*/ |