3 * The CAST-128 block cipher
5 * (c) 2000 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Catacomb.
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.
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.
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,
28 /*----- Header files ------------------------------------------------------*/
35 #include <mLib/bits.h>
38 #include "cast-base.h"
43 /*----- Global variables --------------------------------------------------*/
45 const octet cast128_keysz[] = { KSZ_RANGE, CAST128_KEYSZ, 0, 16, 1 };
47 /*----- Main code ---------------------------------------------------------*/
49 /* --- @cast128_init@ --- *
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
57 * Use: Initializes a CAST-128 key buffer. CAST-128 accepts
58 * 128-bit keys or shorter.
61 void cast128_init(cast128_ctx *k, const void *buf, size_t sz)
66 uint32 a, b, c, d, aa, bb, cc, dd;
68 /* --- Fiddle with the key size a bit --- */
70 KSZ_ASSERT(cast128, sz);
77 /* --- Read the key into the array --- */
85 aa |= ((uint32)*p++ << b);
101 /* --- Read the key words out --- */
103 a = kk[0]; b = kk[1]; c = kk[2]; d = kk[3];
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)
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)
149 #define SK(w, x, y, z) \
150 cast_sk[0][w] ^ cast_sk[1][x] ^ cast_sk[2][y] ^ cast_sk[3][z]
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];
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;
223 /* --- @cast128_eblk@, @cast128_dblk@ --- *
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
231 * Use: Low-level block encryption and decryption.
234 void cast128_eblk(const cast128_ctx *k, const uint32 *s, uint32 *d)
236 uint32 a = s[0], b = s[1];
237 const uint32 *km = k->km;
238 const octet *kr = k->kr;
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);
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);
266 void cast128_dblk(const cast128_ctx *k, const uint32 *s, uint32 *d)
268 uint32 a = s[0], b = s[1];
269 const uint32 *km = k->km + k->r;
270 const octet *kr = k->kr + k->r;
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);
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);
298 BLKC_TEST(CAST128, cast128)
300 /*----- That's all, folks -------------------------------------------------*/