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8875ece6 | 1 | /* -*-c-*- |
2 | * | |
b817bfc6 | 3 | * $Id: square.c,v 1.3 2004/04/08 01:36:15 mdw Exp $ |
8875ece6 | 4 | * |
5 | * The Square block cipher | |
6 | * | |
7 | * (c) 2000 Straylight/Edgeware | |
8 | */ | |
9 | ||
45c0fd36 | 10 | /*----- Licensing notice --------------------------------------------------* |
8875ece6 | 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 | * |
8875ece6 | 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 | * |
8875ece6 | 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 | ||
8875ece6 | 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 "square.h" | |
41 | #include "square-tab.h" | |
42 | ||
43 | /*----- Global variables --------------------------------------------------*/ | |
44 | ||
45 | const octet square_keysz[] = { KSZ_RANGE, SQUARE_KEYSZ, 4, 16, 4 }; | |
46 | ||
47 | /*----- Constant tables ---------------------------------------------------*/ | |
48 | ||
49 | static const octet S[256] = SQUARE_S, SI[256] = SQUARE_SI; | |
50 | static const uint32 T[4][256] = SQUARE_T, TI[4][256] = SQUARE_TI; | |
51 | static const uint32 U[4][256] = SQUARE_U; | |
52 | static const octet rcon[] = SQUARE_RCON; | |
53 | ||
54 | /*----- Main code ---------------------------------------------------------*/ | |
55 | ||
8875ece6 | 56 | /* --- @square_init@ --- * |
57 | * | |
58 | * Arguments: @square_ctx *k@ = pointer to context to initialize | |
59 | * @const void *buf@ = pointer to buffer of key material | |
60 | * @size_t sz@ = size of the key material | |
61 | * | |
62 | * Returns: --- | |
63 | * | |
64 | * Use: Initializes a Square context with a particular key. Square | |
65 | * keys must be a multiple of 32 bits long, and may be at most | |
66 | * 128 bits. | |
67 | */ | |
68 | ||
69 | void square_init(square_ctx *k, const void *buf, size_t sz) | |
70 | { | |
71 | unsigned nk, nr, nw; | |
72 | unsigned i, j, jj; | |
73 | const octet *p; | |
74 | uint32 ww; | |
75 | uint32 kk[SQUARE_KWORDS]; | |
76 | ||
77 | /* --- Sort out the key size --- */ | |
78 | ||
79 | KSZ_ASSERT(square, sz); | |
80 | nk = sz / 4; | |
81 | ||
82 | /* --- Fetch the first key words out --- */ | |
83 | ||
84 | p = buf; | |
85 | for (i = 0; i < nk; i++) { | |
86 | kk[i] = LOAD32_L(p); | |
87 | p += 4; | |
88 | } | |
89 | nr = 8; | |
90 | ||
91 | /* --- Expand this material to fill the rest of the table --- */ | |
92 | ||
93 | nw = (nr + 1) * 4; | |
94 | ww = kk[i - 1]; | |
95 | p = rcon; | |
96 | for (; i < nw; i++) { | |
97 | uint32 w = kk[i - nk]; | |
98 | if (i % nk == 0) { | |
99 | ww = ROR32(ww, 8); | |
100 | w ^= ww ^ *p++; | |
101 | } else | |
102 | w ^= ww; | |
103 | kk[i] = ww = w; | |
104 | } | |
105 | ||
106 | /* --- Make the encryption and decryption keys --- */ | |
107 | ||
108 | for (i = 0; i < nr * 4; i++) { | |
109 | uint32 w = kk[i]; | |
45c0fd36 | 110 | k->w[i] = (U[0][U8(w >> 0)] ^ U[1][U8(w >> 8)] ^ |
8875ece6 | 111 | U[2][U8(w >> 16)] ^ U[3][U8(w >> 24)]); |
112 | } | |
113 | for (; i < nw; i++) | |
114 | k->w[i] = kk[i]; | |
115 | ||
116 | jj = nw; | |
117 | for (i = 0; i < nr * 4; i += 4) { | |
118 | jj -= 4; | |
119 | for (j = 0; j < 4; j++) | |
120 | k->wi[i + j] = kk[jj + j]; | |
121 | } | |
122 | for (j = 0; j < 4; j++) | |
123 | k->wi[i + j] = k->w[j]; | |
124 | ||
125 | BURN(kk); | |
126 | } | |
127 | ||
128 | /* --- @square_eblk@, @square_dblk@ --- * | |
129 | * | |
130 | * Arguments: @const square_ctx *k@ = pointer to Square context | |
131 | * @const uint32 s[4]@ = pointer to source block | |
132 | * @uint32 d[4]@ = pointer to destination block | |
133 | * | |
134 | * Returns: --- | |
135 | * | |
136 | * Use: Low-level block encryption and decryption. | |
137 | */ | |
138 | ||
b14a0768 | 139 | #define SUB(s, sh, a, b, c, d) \ |
45c0fd36 | 140 | (s[U8((a) >> sh)] << 0 | s[U8((b) >> sh)] << 8 | \ |
b14a0768 | 141 | s[U8((c) >> sh)] << 16 | s[U8((d) >> sh)] << 24) |
142 | ||
143 | #define MIX(t, sh, a, b, c, d) \ | |
144 | (t[0][U8((a) >> sh)] ^ t[1][U8((b) >> sh)] ^ \ | |
145 | t[2][U8((c) >> sh)] ^ t[3][U8((d) >> sh)]) | |
8875ece6 | 146 | |
b14a0768 | 147 | #define DO(what, t, aa, bb, cc, dd, a, b, c, d, w) do { \ |
45c0fd36 MW |
148 | aa = what(t, 0, a, b, c, d) ^ *w++; \ |
149 | bb = what(t, 8, a, b, c, d) ^ *w++; \ | |
b14a0768 | 150 | cc = what(t, 16, a, b, c, d) ^ *w++; \ |
151 | dd = what(t, 24, a, b, c, d) ^ *w++; \ | |
8875ece6 | 152 | } while (0) |
153 | ||
154 | void square_eblk(const square_ctx *k, const uint32 *s, uint32 *dst) | |
155 | { | |
156 | uint32 a = s[0], b = s[1], c = s[2], d = s[3]; | |
157 | uint32 aa, bb, cc, dd; | |
78ec50fa | 158 | const uint32 *w = k->w; |
8875ece6 | 159 | |
160 | a ^= *w++; b ^= *w++; c ^= *w++; d ^= *w++; | |
161 | ||
b14a0768 | 162 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); |
163 | DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w); | |
164 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); | |
165 | DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w); | |
166 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); | |
167 | DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w); | |
168 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); | |
169 | DO(SUB, S, a, b, c, d, aa, bb, cc, dd, w); | |
8875ece6 | 170 | |
171 | dst[0] = a; dst[1] = b; dst[2] = c; dst[3] = d; | |
172 | } | |
173 | ||
174 | void square_dblk(const square_ctx *k, const uint32 *s, uint32 *dst) | |
175 | { | |
176 | uint32 a = s[0], b = s[1], c = s[2], d = s[3]; | |
177 | uint32 aa, bb, cc, dd; | |
78ec50fa | 178 | const uint32 *w = k->wi; |
8875ece6 | 179 | |
180 | a ^= *w++; b ^= *w++; c ^= *w++; d ^= *w++; | |
181 | ||
b14a0768 | 182 | DO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); |
183 | DO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w); | |
184 | DO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); | |
185 | DO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w); | |
186 | DO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); | |
187 | DO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w); | |
188 | DO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); | |
189 | DO(SUB, SI, a, b, c, d, aa, bb, cc, dd, w); | |
8875ece6 | 190 | |
191 | dst[0] = a; dst[1] = b; dst[2] = c; dst[3] = d; | |
192 | } | |
193 | ||
194 | BLKC_TEST(SQUARE, square) | |
195 | ||
196 | /*----- That's all, folks -------------------------------------------------*/ |