3 * The CAST-256 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 cast256_keysz
[] = { KSZ_RANGE
, CAST256_KEYSZ
, 0, 32, 1 };
47 /*----- Main code ---------------------------------------------------------*/
49 /* --- @cast256_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-256 key buffer. CAST-256 accepts
58 * 256-bit keys or shorter.
61 void cast256_init(cast256_ctx
*k
, const void *buf
, size_t sz
)
68 uint32 a
, b
, c
, d
, e
, f
, g
, h
;
72 /* --- Fiddle with the key size --- */
74 KSZ_ASSERT(cast256
, sz
);
76 /* --- Read the key into the array --- */
84 a
|= ((uint32
)*p
++ << b
);
100 /* --- Read the key words out --- */
102 a
= kk
[0]; b
= kk
[1]; c
= kk
[2]; d
= kk
[3];
103 e
= kk
[4]; f
= kk
[5]; g
= kk
[6]; h
= kk
[7];
105 #define ROOT2 0x5a827999
106 #define ROOT3 0x6ed9eba1
113 for (i
= 0; i
< 12; i
++) {
114 for (j
= 0; j
< 2; j
++) {
115 CAST_R1(m
, r
, g
, h
); m
+= ROOT3
; r
= (r
+ 17) & 0x1f;
116 CAST_R2(m
, r
, f
, g
); m
+= ROOT3
; r
= (r
+ 17) & 0x1f;
117 CAST_R3(m
, r
, e
, f
); m
+= ROOT3
; r
= (r
+ 17) & 0x1f;
118 CAST_R1(m
, r
, d
, e
); m
+= ROOT3
; r
= (r
+ 17) & 0x1f;
119 CAST_R2(m
, r
, c
, d
); m
+= ROOT3
; r
= (r
+ 17) & 0x1f;
120 CAST_R3(m
, r
, b
, c
); m
+= ROOT3
; r
= (r
+ 17) & 0x1f;
121 CAST_R1(m
, r
, a
, b
); m
+= ROOT3
; r
= (r
+ 17) & 0x1f;
122 CAST_R2(m
, r
, h
, a
); m
+= ROOT3
; r
= (r
+ 17) & 0x1f;
124 km
[0] = h
; km
[1] = f
; km
[2] = d
; km
[3] = b
;
125 kr
[0] = a
& 0x1f; kr
[1] = c
& 0x1f; kr
[2] = e
& 0x1f; kr
[3] = g
& 0x1f;
130 /* --- @cast256_eblk@, @cast256_dblk@ --- *
132 * Arguments: @const cast256_ctx *k@ = pointer to key block
133 * @const uint32 s[2]@ = pointer to source block
134 * @uint32 d[2]@ = pointer to destination block
138 * Use: Low-level block encryption and decryption.
141 #define Q0(k, r, a, b, c, d) do { \
142 CAST_R1(k[0], r[0], c, d); \
143 CAST_R2(k[1], r[1], b, c); \
144 CAST_R3(k[2], r[2], a, b); \
145 CAST_R1(k[3], r[3], d, a); \
148 #define Q1(k, r, a, b, c, d) do { \
149 CAST_R1(k[3], r[3], d, a); \
150 CAST_R3(k[2], r[2], a, b); \
151 CAST_R2(k[1], r[1], b, c); \
152 CAST_R1(k[0], r[0], c, d); \
155 void cast256_eblk(const cast256_ctx
*k
, const uint32
*s
, uint32
*d
)
157 uint32 aa
= s
[0], bb
= s
[1], cc
= s
[2], dd
= s
[3];
158 const uint32
*km
= k
->km
;
159 const octet
*kr
= k
->kr
;
161 Q0(km
, kr
, aa
, bb
, cc
, dd
); km
+= 4; kr
+= 4;
162 Q0(km
, kr
, aa
, bb
, cc
, dd
); km
+= 4; kr
+= 4;
163 Q0(km
, kr
, aa
, bb
, cc
, dd
); km
+= 4; kr
+= 4;
164 Q0(km
, kr
, aa
, bb
, cc
, dd
); km
+= 4; kr
+= 4;
165 Q0(km
, kr
, aa
, bb
, cc
, dd
); km
+= 4; kr
+= 4;
166 Q0(km
, kr
, aa
, bb
, cc
, dd
); km
+= 4; kr
+= 4;
168 Q1(km
, kr
, aa
, bb
, cc
, dd
); km
+= 4; kr
+= 4;
169 Q1(km
, kr
, aa
, bb
, cc
, dd
); km
+= 4; kr
+= 4;
170 Q1(km
, kr
, aa
, bb
, cc
, dd
); km
+= 4; kr
+= 4;
171 Q1(km
, kr
, aa
, bb
, cc
, dd
); km
+= 4; kr
+= 4;
172 Q1(km
, kr
, aa
, bb
, cc
, dd
); km
+= 4; kr
+= 4;
173 Q1(km
, kr
, aa
, bb
, cc
, dd
); km
+= 4; kr
+= 4;
175 d
[0] = aa
; d
[1] = bb
; d
[2] = cc
; d
[3] = dd
;
178 void cast256_dblk(const cast256_ctx
*k
, const uint32
*s
, uint32
*d
)
180 uint32 aa
= s
[0], bb
= s
[1], cc
= s
[2], dd
= s
[3];
181 const uint32
*km
= k
->km
+ 48;
182 const octet
*kr
= k
->kr
+ 48;
184 km
-= 4; kr
-= 4; Q0(km
, kr
, aa
, bb
, cc
, dd
);
185 km
-= 4; kr
-= 4; Q0(km
, kr
, aa
, bb
, cc
, dd
);
186 km
-= 4; kr
-= 4; Q0(km
, kr
, aa
, bb
, cc
, dd
);
187 km
-= 4; kr
-= 4; Q0(km
, kr
, aa
, bb
, cc
, dd
);
188 km
-= 4; kr
-= 4; Q0(km
, kr
, aa
, bb
, cc
, dd
);
189 km
-= 4; kr
-= 4; Q0(km
, kr
, aa
, bb
, cc
, dd
);
191 km
-= 4; kr
-= 4; Q1(km
, kr
, aa
, bb
, cc
, dd
);
192 km
-= 4; kr
-= 4; Q1(km
, kr
, aa
, bb
, cc
, dd
);
193 km
-= 4; kr
-= 4; Q1(km
, kr
, aa
, bb
, cc
, dd
);
194 km
-= 4; kr
-= 4; Q1(km
, kr
, aa
, bb
, cc
, dd
);
195 km
-= 4; kr
-= 4; Q1(km
, kr
, aa
, bb
, cc
, dd
);
196 km
-= 4; kr
-= 4; Q1(km
, kr
, aa
, bb
, cc
, dd
);
198 d
[0] = aa
; d
[1] = bb
; d
[2] = cc
; d
[3] = dd
;
201 BLKC_TEST(CAST256
, cast256
)
203 /*----- That's all, folks -------------------------------------------------*/