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8dd8c294 | 1 | /* -*-c-*- |
2 | * | |
b817bfc6 | 3 | * $Id: serpent.c,v 1.2 2004/04/08 01:36:15 mdw Exp $ |
8dd8c294 | 4 | * |
5 | * The Serpent block cipher | |
6 | * | |
7 | * (c) 2000 Straylight/Edgeware | |
8 | */ | |
9 | ||
45c0fd36 | 10 | /*----- Licensing notice --------------------------------------------------* |
8dd8c294 | 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. | |
45c0fd36 | 18 | * |
8dd8c294 | 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. | |
45c0fd36 | 23 | * |
8dd8c294 | 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 | ||
8dd8c294 | 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 "serpent.h" | |
40 | #include "serpent-sbox.h" | |
41 | ||
42 | /*----- Global variables --------------------------------------------------*/ | |
43 | ||
44 | const octet serpent_keysz[] = { KSZ_RANGE, SERPENT_KEYSZ, 0, 32, 1 }; | |
45 | ||
46 | /*----- Main code ---------------------------------------------------------*/ | |
47 | ||
48 | /* --- @serpent_init@ --- * | |
49 | * | |
50 | * Arguments: @serpent_ctx *k@ = pointer to context block to initialize | |
51 | * @const void *buf@ = pointer to input buffer | |
52 | * @size_t sz@ = size of input buffer | |
53 | * | |
54 | * Returns: --- | |
55 | * | |
56 | * Use: Initializes a Serpent context. The key may be any length of | |
57 | * up to 32 bytes (256 bits). | |
58 | */ | |
59 | ||
60 | void serpent_init(serpent_ctx *k, const void *buf, size_t sz) | |
61 | { | |
62 | uint32 a; | |
63 | unsigned b; | |
64 | const octet *p, *q; | |
65 | size_t i; | |
66 | uint32 pk[8 + 132]; | |
67 | ||
68 | KSZ_ASSERT(serpent, sz); | |
69 | ||
70 | /* --- Read the key into the buffer --- */ | |
71 | ||
72 | if (sz > 32) | |
73 | sz = 32; | |
74 | i = 0; p = buf; q = p + sz; | |
75 | a = 0; b = 0; | |
76 | while (p < q) { | |
77 | a |= (uint32)*p++ << b; | |
78 | b += 8; | |
79 | if (b == 32) { | |
80 | pk[i++] = a; | |
81 | a = 0; b = 0; | |
82 | } | |
83 | } | |
84 | ||
85 | /* --- Pad short keys --- */ | |
86 | ||
87 | if (i < 8) { | |
88 | a |= 0x01 << b; | |
89 | b += 8; | |
90 | pk[i++] = a; | |
91 | for (; i < 8; i++) | |
92 | pk[i] = 0; | |
93 | } | |
94 | ||
95 | /* --- Expand the prekeys to fill the buffer --- */ | |
96 | ||
97 | for (i = 8; i < 8 + 132; i++) { | |
98 | uint32 x = (pk[i - 8] ^ pk[i - 5] ^ pk[i - 3] ^ pk[i - 1] ^ | |
99 | (i - 8) ^ 0x9e3779b9); | |
100 | k->k[i - 8] = pk[i] = ROL32(x, 11); | |
101 | } | |
102 | ||
103 | /* --- Now substitute everything --- */ | |
104 | ||
105 | i = 0; | |
106 | goto midway; | |
107 | while (i < 132) { | |
108 | #define KSUB(r) do { \ | |
109 | uint32 a, b, c, d; \ | |
110 | a = k->k[i]; b = k->k[i + 1]; c = k->k[i + 2]; d = k->k[i + 3]; \ | |
111 | S##r(a, b, c, d); \ | |
112 | k->k[i] = a; k->k[i + 1] = b; k->k[i + 2] = c; k->k[i + 3] = d; \ | |
113 | i += 4; \ | |
114 | } while (0) | |
115 | KSUB(2); KSUB(1); KSUB(0); KSUB(7); | |
116 | KSUB(6); KSUB(5); KSUB(4); | |
117 | midway: | |
118 | KSUB(3); | |
119 | #undef KSUB | |
120 | } | |
121 | } | |
122 | ||
123 | /* --- @serpent_eblk@, @serpent_dblk@ --- * | |
124 | * | |
125 | * Arguments: @const serpent_ctx *k@ = pointer to key context | |
126 | * @const uint32 s[4]@ = pointer to source block | |
127 | * @uint32 d[4]@ = pointer to destination block | |
128 | * | |
129 | * Returns: --- | |
130 | * | |
131 | * Use: Low-level block encryption. | |
132 | */ | |
133 | ||
134 | #define EROUND(a, b, c, d, r, k) do { \ | |
135 | a ^= *k++; b ^= *k++; c ^= *k++; d ^= *k++; \ | |
136 | S##r(a, b, c, d); \ | |
137 | a = ROL32(a, 13); c = ROL32(c, 3); b ^= a ^ c; d ^= c ^ (a << 3); \ | |
45c0fd36 MW |
138 | b = ROL32(b, 1); d = ROL32(d, 7); a ^= b ^ d; c ^= d ^ (b << 7); \ |
139 | a = ROL32(a, 5); c = ROL32(c, 22); \ | |
8dd8c294 | 140 | } while (0) |
141 | ||
142 | #define DROUND(a, b, c, d, r, k) do { \ | |
143 | IS##r(a, b, c, d); \ | |
144 | d ^= *--k; c ^= *--k; b ^= *--k; a ^= *--k; \ | |
45c0fd36 MW |
145 | a = ROR32(a, 5); c = ROR32(c, 22); a ^= b ^ d; c ^= d ^ (b << 7); \ |
146 | b = ROR32(b, 1); d = ROR32(d, 7); b ^= a ^ c; d ^= c ^ (a << 3); \ | |
8dd8c294 | 147 | a = ROR32(a, 13); c = ROR32(c, 3); \ |
148 | } while (0) | |
149 | ||
150 | void serpent_eblk(const serpent_ctx *k, const uint32 *s, uint32 *d) | |
151 | { | |
152 | uint32 aa = s[0], bb = s[1], cc = s[2], dd = s[3]; | |
153 | const uint32 *kk = k->k; | |
154 | ||
155 | EROUND(aa, bb, cc, dd, 0, kk); EROUND(aa, bb, cc, dd, 1, kk); | |
156 | EROUND(aa, bb, cc, dd, 2, kk); EROUND(aa, bb, cc, dd, 3, kk); | |
157 | EROUND(aa, bb, cc, dd, 4, kk); EROUND(aa, bb, cc, dd, 5, kk); | |
158 | EROUND(aa, bb, cc, dd, 6, kk); EROUND(aa, bb, cc, dd, 7, kk); | |
159 | ||
160 | EROUND(aa, bb, cc, dd, 0, kk); EROUND(aa, bb, cc, dd, 1, kk); | |
161 | EROUND(aa, bb, cc, dd, 2, kk); EROUND(aa, bb, cc, dd, 3, kk); | |
162 | EROUND(aa, bb, cc, dd, 4, kk); EROUND(aa, bb, cc, dd, 5, kk); | |
163 | EROUND(aa, bb, cc, dd, 6, kk); EROUND(aa, bb, cc, dd, 7, kk); | |
164 | ||
165 | EROUND(aa, bb, cc, dd, 0, kk); EROUND(aa, bb, cc, dd, 1, kk); | |
166 | EROUND(aa, bb, cc, dd, 2, kk); EROUND(aa, bb, cc, dd, 3, kk); | |
167 | EROUND(aa, bb, cc, dd, 4, kk); EROUND(aa, bb, cc, dd, 5, kk); | |
168 | EROUND(aa, bb, cc, dd, 6, kk); EROUND(aa, bb, cc, dd, 7, kk); | |
169 | ||
170 | EROUND(aa, bb, cc, dd, 0, kk); EROUND(aa, bb, cc, dd, 1, kk); | |
171 | EROUND(aa, bb, cc, dd, 2, kk); EROUND(aa, bb, cc, dd, 3, kk); | |
172 | EROUND(aa, bb, cc, dd, 4, kk); EROUND(aa, bb, cc, dd, 5, kk); | |
173 | EROUND(aa, bb, cc, dd, 6, kk); | |
174 | ||
175 | aa ^= *kk++; bb ^= *kk++; cc ^= *kk++; dd ^= *kk++; | |
176 | S7(aa, bb, cc, dd); | |
177 | aa ^= *kk++; bb ^= *kk++; cc ^= *kk++; dd ^= *kk++; | |
178 | d[0] = aa; d[1] = bb; d[2] = cc; d[3] = dd; | |
179 | } | |
180 | ||
181 | void serpent_dblk(const serpent_ctx *k, const uint32 *s, uint32 *d) | |
182 | { | |
183 | uint32 aa = s[0], bb = s[1], cc = s[2], dd = s[3]; | |
184 | const uint32 *kk = k->k + 132; | |
185 | ||
186 | dd ^= *--kk; cc ^= *--kk; bb ^= *--kk; aa ^= *--kk; | |
187 | ||
188 | DROUND(aa, bb, cc, dd, 7, kk); DROUND(aa, bb, cc, dd, 6, kk); | |
189 | DROUND(aa, bb, cc, dd, 5, kk); DROUND(aa, bb, cc, dd, 4, kk); | |
190 | DROUND(aa, bb, cc, dd, 3, kk); DROUND(aa, bb, cc, dd, 2, kk); | |
191 | DROUND(aa, bb, cc, dd, 1, kk); DROUND(aa, bb, cc, dd, 0, kk); | |
192 | ||
193 | DROUND(aa, bb, cc, dd, 7, kk); DROUND(aa, bb, cc, dd, 6, kk); | |
194 | DROUND(aa, bb, cc, dd, 5, kk); DROUND(aa, bb, cc, dd, 4, kk); | |
195 | DROUND(aa, bb, cc, dd, 3, kk); DROUND(aa, bb, cc, dd, 2, kk); | |
196 | DROUND(aa, bb, cc, dd, 1, kk); DROUND(aa, bb, cc, dd, 0, kk); | |
197 | ||
198 | DROUND(aa, bb, cc, dd, 7, kk); DROUND(aa, bb, cc, dd, 6, kk); | |
199 | DROUND(aa, bb, cc, dd, 5, kk); DROUND(aa, bb, cc, dd, 4, kk); | |
200 | DROUND(aa, bb, cc, dd, 3, kk); DROUND(aa, bb, cc, dd, 2, kk); | |
201 | DROUND(aa, bb, cc, dd, 1, kk); DROUND(aa, bb, cc, dd, 0, kk); | |
202 | ||
203 | DROUND(aa, bb, cc, dd, 7, kk); DROUND(aa, bb, cc, dd, 6, kk); | |
204 | DROUND(aa, bb, cc, dd, 5, kk); DROUND(aa, bb, cc, dd, 4, kk); | |
205 | DROUND(aa, bb, cc, dd, 3, kk); DROUND(aa, bb, cc, dd, 2, kk); | |
206 | DROUND(aa, bb, cc, dd, 1, kk); | |
207 | ||
208 | IS0(aa, bb, cc, dd); | |
209 | dd ^= *--kk; cc ^= *--kk; bb ^= *--kk; aa ^= *--kk; | |
210 | d[0] = aa; d[1] = bb; d[2] = cc; d[3] = dd; | |
211 | } | |
212 | ||
213 | BLKC_TEST(SERPENT, serpent) | |
214 | ||
215 | /*----- That's all, folks -------------------------------------------------*/ |