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1 | /* -*-c-*- |
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2 | * |
3 | * The CAST-128 block cipher |
4 | * |
5 | * (c) 2000 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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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. |
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16 | * |
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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. |
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21 | * |
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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 | |
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28 | /*----- Header files ------------------------------------------------------*/ |
29 | |
30 | #include <assert.h> |
31 | #include <stdio.h> |
32 | #include <stdlib.h> |
33 | #include <string.h> |
34 | |
35 | #include <mLib/bits.h> |
36 | |
37 | #include "blkc.h" |
38 | #include "cast-base.h" |
39 | #include "cast128.h" |
40 | #include "gcipher.h" |
41 | #include "paranoia.h" |
42 | |
43 | /*----- Global variables --------------------------------------------------*/ |
44 | |
45 | const octet cast128_keysz[] = { KSZ_RANGE, CAST128_KEYSZ, 0, 16, 1 }; |
46 | |
47 | /*----- Main code ---------------------------------------------------------*/ |
48 | |
49 | /* --- @cast128_init@ --- * |
50 | * |
51 | * Arguments: @cast128_ctx *k@ = pointer to key block to fill in |
52 | * @const void *buf@ = pointer to buffer of key material |
53 | * @size_t sz@ = size of key material |
54 | * |
55 | * Returns: --- |
56 | * |
57 | * Use: Initializes a CAST-128 key buffer. CAST-128 accepts |
58 | * 128-bit keys or shorter. |
59 | */ |
60 | |
61 | void cast128_init(cast128_ctx *k, const void *buf, size_t sz) |
62 | { |
63 | const octet *p = buf; |
64 | uint32 kk[4]; |
65 | unsigned i; |
66 | uint32 a, b, c, d, aa, bb, cc, dd; |
67 | |
68 | /* --- Fiddle with the key size a bit --- */ |
69 | |
70 | KSZ_ASSERT(cast128, sz); |
71 | |
72 | if (sz > 10) |
73 | k->r = 16; |
74 | else |
75 | k->r = 12; |
76 | |
77 | /* --- Read the key into the array --- */ |
78 | |
79 | i = 0; |
80 | b = 32; aa = 0; |
81 | for (;;) { |
82 | if (!sz) |
83 | break; |
84 | b -= 8; |
85 | aa |= ((uint32)*p++ << b); |
86 | sz--; |
87 | if (b == 0) { |
88 | kk[i++] = aa; |
89 | if (i == 4) |
90 | break; |
91 | aa = 0; |
92 | b = 32; |
93 | } |
94 | } |
95 | |
96 | for (; i < 4; i++) { |
97 | kk[i] = aa; |
98 | aa = 0; |
99 | } |
100 | |
101 | /* --- Read the key words out --- */ |
102 | |
103 | a = kk[0]; b = kk[1]; c = kk[2]; d = kk[3]; |
104 | |
105 | #define X_0123 a |
106 | #define X_4567 b |
107 | #define X_89ab c |
108 | #define X_cdef d |
109 | |
110 | #define X_0 U8(X_0123 >> 24) |
111 | #define X_1 U8(X_0123 >> 16) |
112 | #define X_2 U8(X_0123 >> 8) |
113 | #define X_3 U8(X_0123 >> 0) |
114 | #define X_4 U8(X_4567 >> 24) |
115 | #define X_5 U8(X_4567 >> 16) |
116 | #define X_6 U8(X_4567 >> 8) |
117 | #define X_7 U8(X_4567 >> 0) |
118 | #define X_8 U8(X_89ab >> 24) |
119 | #define X_9 U8(X_89ab >> 16) |
120 | #define X_a U8(X_89ab >> 8) |
121 | #define X_b U8(X_89ab >> 0) |
122 | #define X_c U8(X_cdef >> 24) |
123 | #define X_d U8(X_cdef >> 16) |
124 | #define X_e U8(X_cdef >> 8) |
125 | #define X_f U8(X_cdef >> 0) |
126 | |
127 | #define Z_0123 aa |
128 | #define Z_4567 bb |
129 | #define Z_89ab cc |
130 | #define Z_cdef dd |
131 | |
132 | #define Z_0 U8(Z_0123 >> 24) |
133 | #define Z_1 U8(Z_0123 >> 16) |
134 | #define Z_2 U8(Z_0123 >> 8) |
135 | #define Z_3 U8(Z_0123 >> 0) |
136 | #define Z_4 U8(Z_4567 >> 24) |
137 | #define Z_5 U8(Z_4567 >> 16) |
138 | #define Z_6 U8(Z_4567 >> 8) |
139 | #define Z_7 U8(Z_4567 >> 0) |
140 | #define Z_8 U8(Z_89ab >> 24) |
141 | #define Z_9 U8(Z_89ab >> 16) |
142 | #define Z_a U8(Z_89ab >> 8) |
143 | #define Z_b U8(Z_89ab >> 0) |
144 | #define Z_c U8(Z_cdef >> 24) |
145 | #define Z_d U8(Z_cdef >> 16) |
146 | #define Z_e U8(Z_cdef >> 8) |
147 | #define Z_f U8(Z_cdef >> 0) |
148 | |
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149 | #define SK(w, x, y, z) \ |
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150 | cast_sk[0][w] ^ cast_sk[1][x] ^ cast_sk[2][y] ^ cast_sk[3][z] |
151 | |
152 | i = 0; |
153 | Z_0123 = X_0123 ^ SK(X_d, X_f, X_c, X_e) ^ cast_sk[2][X_8]; |
154 | Z_4567 = X_89ab ^ SK(Z_0, Z_2, Z_1, Z_3) ^ cast_sk[3][X_a]; |
155 | Z_89ab = X_cdef ^ SK(Z_7, Z_6, Z_5, Z_4) ^ cast_sk[0][X_9]; |
156 | Z_cdef = X_4567 ^ SK(Z_a, Z_9, Z_b, Z_8) ^ cast_sk[1][X_b]; |
157 | k->km[i++] = SK(Z_8, Z_9, Z_7, Z_6) ^ cast_sk[0][Z_2]; |
158 | k->km[i++] = SK(Z_a, Z_b, Z_5, Z_4) ^ cast_sk[1][Z_6]; |
159 | k->km[i++] = SK(Z_c, Z_d, Z_3, Z_2) ^ cast_sk[2][Z_9]; |
160 | k->km[i++] = SK(Z_e, Z_f, Z_1, Z_0) ^ cast_sk[3][Z_c]; |
161 | X_0123 = Z_89ab ^ SK(Z_5, Z_7, Z_4, Z_6) ^ cast_sk[2][Z_0]; |
162 | X_4567 = Z_0123 ^ SK(X_0, X_2, X_1, X_3) ^ cast_sk[3][Z_2]; |
163 | X_89ab = Z_4567 ^ SK(X_7, X_6, X_5, X_4) ^ cast_sk[0][Z_1]; |
164 | X_cdef = Z_cdef ^ SK(X_a, X_9, X_b, X_8) ^ cast_sk[1][Z_3]; |
165 | k->km[i++] = SK(X_3, X_2, X_c, X_d) ^ cast_sk[0][X_8]; |
166 | k->km[i++] = SK(X_1, X_0, X_e, X_f) ^ cast_sk[1][X_d]; |
167 | k->km[i++] = SK(X_7, X_6, X_8, X_9) ^ cast_sk[2][X_3]; |
168 | k->km[i++] = SK(X_5, X_4, X_a, X_b) ^ cast_sk[3][X_7]; |
169 | Z_0123 = X_0123 ^ SK(X_d, X_f, X_c, X_e) ^ cast_sk[2][X_8]; |
170 | Z_4567 = X_89ab ^ SK(Z_0, Z_2, Z_1, Z_3) ^ cast_sk[3][X_a]; |
171 | Z_89ab = X_cdef ^ SK(Z_7, Z_6, Z_5, Z_4) ^ cast_sk[0][X_9]; |
172 | Z_cdef = X_4567 ^ SK(Z_a, Z_9, Z_b, Z_8) ^ cast_sk[1][X_b]; |
173 | k->km[i++] = SK(Z_3, Z_2, Z_c, Z_d) ^ cast_sk[0][Z_9]; |
174 | k->km[i++] = SK(Z_1, Z_0, Z_e, Z_f) ^ cast_sk[1][Z_c]; |
175 | k->km[i++] = SK(Z_7, Z_6, Z_8, Z_9) ^ cast_sk[2][Z_2]; |
176 | k->km[i++] = SK(Z_5, Z_4, Z_a, Z_b) ^ cast_sk[3][Z_6]; |
177 | X_0123 = Z_89ab ^ SK(Z_5, Z_7, Z_4, Z_6) ^ cast_sk[2][Z_0]; |
178 | X_4567 = Z_0123 ^ SK(X_0, X_2, X_1, X_3) ^ cast_sk[3][Z_2]; |
179 | X_89ab = Z_4567 ^ SK(X_7, X_6, X_5, X_4) ^ cast_sk[0][Z_1]; |
180 | X_cdef = Z_cdef ^ SK(X_a, X_9, X_b, X_8) ^ cast_sk[1][Z_3]; |
181 | k->km[i++] = SK(X_8, X_9, X_7, X_6) ^ cast_sk[0][X_3]; |
182 | k->km[i++] = SK(X_a, X_b, X_5, X_4) ^ cast_sk[1][X_7]; |
183 | k->km[i++] = SK(X_c, X_d, X_3, X_2) ^ cast_sk[2][X_8]; |
184 | k->km[i++] = SK(X_e, X_f, X_1, X_0) ^ cast_sk[3][X_d]; |
185 | |
186 | i = 0; |
187 | Z_0123 = X_0123 ^ SK(X_d, X_f, X_c, X_e) ^ cast_sk[2][X_8]; |
188 | Z_4567 = X_89ab ^ SK(Z_0, Z_2, Z_1, Z_3) ^ cast_sk[3][X_a]; |
189 | Z_89ab = X_cdef ^ SK(Z_7, Z_6, Z_5, Z_4) ^ cast_sk[0][X_9]; |
190 | Z_cdef = X_4567 ^ SK(Z_a, Z_9, Z_b, Z_8) ^ cast_sk[1][X_b]; |
191 | k->kr[i++] = (SK(Z_8, Z_9, Z_7, Z_6) ^ cast_sk[0][Z_2]) & 0x1f; |
192 | k->kr[i++] = (SK(Z_a, Z_b, Z_5, Z_4) ^ cast_sk[1][Z_6]) & 0x1f; |
193 | k->kr[i++] = (SK(Z_c, Z_d, Z_3, Z_2) ^ cast_sk[2][Z_9]) & 0x1f; |
194 | k->kr[i++] = (SK(Z_e, Z_f, Z_1, Z_0) ^ cast_sk[3][Z_c]) & 0x1f; |
195 | X_0123 = Z_89ab ^ SK(Z_5, Z_7, Z_4, Z_6) ^ cast_sk[2][Z_0]; |
196 | X_4567 = Z_0123 ^ SK(X_0, X_2, X_1, X_3) ^ cast_sk[3][Z_2]; |
197 | X_89ab = Z_4567 ^ SK(X_7, X_6, X_5, X_4) ^ cast_sk[0][Z_1]; |
198 | X_cdef = Z_cdef ^ SK(X_a, X_9, X_b, X_8) ^ cast_sk[1][Z_3]; |
199 | k->kr[i++] = (SK(X_3, X_2, X_c, X_d) ^ cast_sk[0][X_8]) & 0x1f; |
200 | k->kr[i++] = (SK(X_1, X_0, X_e, X_f) ^ cast_sk[1][X_d]) & 0x1f; |
201 | k->kr[i++] = (SK(X_7, X_6, X_8, X_9) ^ cast_sk[2][X_3]) & 0x1f; |
202 | k->kr[i++] = (SK(X_5, X_4, X_a, X_b) ^ cast_sk[3][X_7]) & 0x1f; |
203 | Z_0123 = X_0123 ^ SK(X_d, X_f, X_c, X_e) ^ cast_sk[2][X_8]; |
204 | Z_4567 = X_89ab ^ SK(Z_0, Z_2, Z_1, Z_3) ^ cast_sk[3][X_a]; |
205 | Z_89ab = X_cdef ^ SK(Z_7, Z_6, Z_5, Z_4) ^ cast_sk[0][X_9]; |
206 | Z_cdef = X_4567 ^ SK(Z_a, Z_9, Z_b, Z_8) ^ cast_sk[1][X_b]; |
207 | k->kr[i++] = (SK(Z_3, Z_2, Z_c, Z_d) ^ cast_sk[0][Z_9]) & 0x1f; |
208 | k->kr[i++] = (SK(Z_1, Z_0, Z_e, Z_f) ^ cast_sk[1][Z_c]) & 0x1f; |
209 | k->kr[i++] = (SK(Z_7, Z_6, Z_8, Z_9) ^ cast_sk[2][Z_2]) & 0x1f; |
210 | k->kr[i++] = (SK(Z_5, Z_4, Z_a, Z_b) ^ cast_sk[3][Z_6]) & 0x1f; |
211 | X_0123 = Z_89ab ^ SK(Z_5, Z_7, Z_4, Z_6) ^ cast_sk[2][Z_0]; |
212 | X_4567 = Z_0123 ^ SK(X_0, X_2, X_1, X_3) ^ cast_sk[3][Z_2]; |
213 | X_89ab = Z_4567 ^ SK(X_7, X_6, X_5, X_4) ^ cast_sk[0][Z_1]; |
214 | X_cdef = Z_cdef ^ SK(X_a, X_9, X_b, X_8) ^ cast_sk[1][Z_3]; |
215 | k->kr[i++] = (SK(X_8, X_9, X_7, X_6) ^ cast_sk[0][X_3]) & 0x1f; |
216 | k->kr[i++] = (SK(X_a, X_b, X_5, X_4) ^ cast_sk[1][X_7]) & 0x1f; |
217 | k->kr[i++] = (SK(X_c, X_d, X_3, X_2) ^ cast_sk[2][X_8]) & 0x1f; |
218 | k->kr[i++] = (SK(X_e, X_f, X_1, X_0) ^ cast_sk[3][X_d]) & 0x1f; |
219 | |
220 | BURN(kk); |
221 | } |
222 | |
223 | /* --- @cast128_eblk@, @cast128_dblk@ --- * |
224 | * |
225 | * Arguments: @const cast128_ctx *k@ = pointer to key block |
226 | * @const uint32 s[2]@ = pointer to source block |
227 | * @uint32 d[2]@ = pointer to destination block |
228 | * |
229 | * Returns: --- |
230 | * |
231 | * Use: Low-level block encryption and decryption. |
232 | */ |
233 | |
234 | void cast128_eblk(const cast128_ctx *k, const uint32 *s, uint32 *d) |
235 | { |
236 | uint32 a = s[0], b = s[1]; |
237 | const uint32 *km = k->km; |
238 | const octet *kr = k->kr; |
239 | |
240 | switch (k->r) { |
241 | default: |
242 | CAST_R1(*km++, *kr++, a, b); |
243 | CAST_R2(*km++, *kr++, b, a); |
244 | CAST_R3(*km++, *kr++, a, b); |
245 | CAST_R1(*km++, *kr++, b, a); |
246 | CAST_R2(*km++, *kr++, a, b); |
247 | CAST_R3(*km++, *kr++, b, a); |
248 | CAST_R1(*km++, *kr++, a, b); |
249 | CAST_R2(*km++, *kr++, b, a); |
250 | CAST_R3(*km++, *kr++, a, b); |
251 | CAST_R1(*km++, *kr++, b, a); |
252 | CAST_R2(*km++, *kr++, a, b); |
253 | CAST_R3(*km++, *kr++, b, a); |
254 | if (k->r == 12) |
255 | break; |
256 | CAST_R1(*km++, *kr++, a, b); |
257 | CAST_R2(*km++, *kr++, b, a); |
258 | CAST_R3(*km++, *kr++, a, b); |
259 | CAST_R1(*km++, *kr++, b, a); |
260 | break; |
261 | } |
262 | |
263 | d[0] = b; d[1] = a; |
264 | } |
265 | |
266 | void cast128_dblk(const cast128_ctx *k, const uint32 *s, uint32 *d) |
267 | { |
268 | uint32 a = s[0], b = s[1]; |
269 | const uint32 *km = k->km + k->r; |
270 | const octet *kr = k->kr + k->r; |
271 | |
272 | switch (k->r) { |
273 | case 16: |
274 | default: |
275 | CAST_R1(*--km, *--kr, a, b); |
276 | CAST_R3(*--km, *--kr, b, a); |
277 | CAST_R2(*--km, *--kr, a, b); |
278 | CAST_R1(*--km, *--kr, b, a); |
279 | case 12: |
280 | CAST_R3(*--km, *--kr, a, b); |
281 | CAST_R2(*--km, *--kr, b, a); |
282 | CAST_R1(*--km, *--kr, a, b); |
283 | CAST_R3(*--km, *--kr, b, a); |
284 | CAST_R2(*--km, *--kr, a, b); |
285 | CAST_R1(*--km, *--kr, b, a); |
286 | CAST_R3(*--km, *--kr, a, b); |
287 | CAST_R2(*--km, *--kr, b, a); |
288 | CAST_R1(*--km, *--kr, a, b); |
289 | CAST_R3(*--km, *--kr, b, a); |
290 | CAST_R2(*--km, *--kr, a, b); |
291 | CAST_R1(*--km, *--kr, b, a); |
292 | break; |
293 | } |
294 | |
295 | d[0] = b; d[1] = a; |
296 | } |
297 | |
298 | BLKC_TEST(CAST128, cast128) |
299 | |
300 | /*----- That's all, folks -------------------------------------------------*/ |