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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: square.c,v 1.3 2004/04/08 01:36:15 mdw Exp $ |
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4 | * |
5 | * The Square 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 | |
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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 | |
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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]; |
110 | k->w[i] = (U[0][U8(w >> 0)] ^ U[1][U8(w >> 8)] ^ |
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 | |
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139 | #define SUB(s, sh, a, b, c, d) \ |
140 | (s[U8((a) >> sh)] << 0 | s[U8((b) >> sh)] << 8 | \ |
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)]) |
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146 | |
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147 | #define DO(what, t, aa, bb, cc, dd, a, b, c, d, w) do { \ |
148 | aa = what(t, 0, a, b, c, d) ^ *w++; \ |
149 | bb = what(t, 8, a, b, c, d) ^ *w++; \ |
150 | cc = what(t, 16, a, b, c, d) ^ *w++; \ |
151 | dd = what(t, 24, a, b, c, d) ^ *w++; \ |
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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; |
158 | uint32 *w = k->w; |
159 | |
160 | a ^= *w++; b ^= *w++; c ^= *w++; d ^= *w++; |
161 | |
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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); |
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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; |
178 | uint32 *w = k->wi; |
179 | |
180 | a ^= *w++; b ^= *w++; c ^= *w++; d ^= *w++; |
181 | |
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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); |
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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 -------------------------------------------------*/ |