3 * $Id: skipjack.c,v 1.5 2004/04/08 01:36:15 mdw Exp $
5 * The Skipjack block cipher
7 * (c) 2000 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
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.
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.
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,
30 /*----- Header files ------------------------------------------------------*/
32 #include <mLib/bits.h>
37 #include "skipjack-tab.h"
39 /*----- Global variables --------------------------------------------------*/
41 const octet skipjack_keysz[] = { KSZ_SET, 10, 0 };
43 /*----- The Skipjack S-box ------------------------------------------------*/
45 static const octet f[256] = SKIPJACK_S;
47 /*----- Main code ---------------------------------------------------------*/
49 /* --- @skipjack_init@ --- *
51 * Arguments: @skipjack_ctx *k@ = pointer to key block
52 * @const void *buf@ = pointer to key buffer
53 * @size_t sz@ = size of key material
57 * Use: Initializes a Skipjack key buffer. The key buffer must be
58 * exactly 10 bytes long.
61 void skipjack_init(skipjack_ctx *k, const void *buf, size_t sz)
65 KSZ_ASSERT(skipjack, sz);
67 k->kb = LOAD32(b + 4);
69 k->kc = U32((crud << 16) | (k->ka >> 16));
70 k->kd = U32((k->ka << 16) | (k->kb >> 16));
71 k->ke = U32((k->kb << 16) | crud);
75 /* --- @skipjack_eblk@, @skipjack_dblk@ --- *
77 * Arguments: @const skipjack_ctx *k@ = pointer to key block
78 * @const uint32 s[2]@ = pointer to source block
79 * @uint32 d[2]@ = pointer to skipjacktination block
83 * Use: Low-level block encryption and decryption.
86 #define G(x, k) do { \
87 octet _x = U8(x >> 8), _y = U8(x); \
88 _x ^= f[_y ^ U8(k >> 24)]; \
89 _y ^= f[_x ^ U8(k >> 16)]; \
90 _x ^= f[_y ^ U8(k >> 8)]; \
91 _y ^= f[_x ^ U8(k >> 0)]; \
95 #define RULE_A(w, x, y, z, n, k) do { \
96 G(w, k); z ^= w ^ n++; \
99 #define RULE_B(w, x, y, z, n, k) do { \
100 x ^= w ^ n++; G(w, k); \
103 void skipjack_eblk(const skipjack_ctx *k, const uint32 *s, uint32 *d)
106 uint16 w = U16(s[0] >> 16), x = U16(s[0]);
107 uint16 y = U16(s[1] >> 16), z = U16(s[1]);
108 uint32 ka = k->ka, kb = k->kb, kc = k->kc, kd = k->kd, ke = k->ke;
110 RULE_A(w, x, y, z, n, ka); RULE_A(z, w, x, y, n, kb);
111 RULE_A(y, z, w, x, n, kc); RULE_A(x, y, z, w, n, kd);
112 RULE_A(w, x, y, z, n, ke); RULE_A(z, w, x, y, n, ka);
113 RULE_A(y, z, w, x, n, kb); RULE_A(x, y, z, w, n, kc);
114 RULE_B(w, x, y, z, n, kd); RULE_B(z, w, x, y, n, ke);
115 RULE_B(y, z, w, x, n, ka); RULE_B(x, y, z, w, n, kb);
116 RULE_B(w, x, y, z, n, kc); RULE_B(z, w, x, y, n, kd);
117 RULE_B(y, z, w, x, n, ke); RULE_B(x, y, z, w, n, ka);
118 RULE_A(w, x, y, z, n, kb); RULE_A(z, w, x, y, n, kc);
119 RULE_A(y, z, w, x, n, kd); RULE_A(x, y, z, w, n, ke);
120 RULE_A(w, x, y, z, n, ka); RULE_A(z, w, x, y, n, kb);
121 RULE_A(y, z, w, x, n, kc); RULE_A(x, y, z, w, n, kd);
122 RULE_B(w, x, y, z, n, ke); RULE_B(z, w, x, y, n, ka);
123 RULE_B(y, z, w, x, n, kb); RULE_B(x, y, z, w, n, kc);
124 RULE_B(w, x, y, z, n, kd); RULE_B(z, w, x, y, n, ke);
125 RULE_B(y, z, w, x, n, ka); RULE_B(x, y, z, w, n, kb);
127 d[0] = ((uint32)w << 16) | (uint32)x;
128 d[1] = ((uint32)y << 16) | (uint32)z;
131 #define G_INV(x, k) do { \
132 octet _x = U8(x >> 8), _y = U8(x); \
133 _y ^= f[_x ^ U8(k >> 0)]; \
134 _x ^= f[_y ^ U8(k >> 8)]; \
135 _y ^= f[_x ^ U8(k >> 16)]; \
136 _x ^= f[_y ^ U8(k >> 24)]; \
137 x = (_x << 8) | _y; \
140 #define RULE_A_INV(w, x, y, z, n, i) do { \
141 w ^= x ^ --n; G_INV(x, i); \
144 #define RULE_B_INV(w, x, y, z, n, i) do { \
145 G_INV(x, i); y ^= x ^ --n; \
148 void skipjack_dblk(const skipjack_ctx *k, const uint32 *s, uint32 *d)
151 uint16 w = U16(s[0] >> 16), x = U16(s[0]);
152 uint16 y = U16(s[1] >> 16), z = U16(s[1]);
153 uint32 ka = k->ka, kb = k->kb, kc = k->kc, kd = k->kd, ke = k->ke;
155 RULE_B_INV(w, x, y, z, n, kb); RULE_B_INV(x, y, z, w, n, ka);
156 RULE_B_INV(y, z, w, x, n, ke); RULE_B_INV(z, w, x, y, n, kd);
157 RULE_B_INV(w, x, y, z, n, kc); RULE_B_INV(x, y, z, w, n, kb);
158 RULE_B_INV(y, z, w, x, n, ka); RULE_B_INV(z, w, x, y, n, ke);
159 RULE_A_INV(w, x, y, z, n, kd); RULE_A_INV(x, y, z, w, n, kc);
160 RULE_A_INV(y, z, w, x, n, kb); RULE_A_INV(z, w, x, y, n, ka);
161 RULE_A_INV(w, x, y, z, n, ke); RULE_A_INV(x, y, z, w, n, kd);
162 RULE_A_INV(y, z, w, x, n, kc); RULE_A_INV(z, w, x, y, n, kb);
163 RULE_B_INV(w, x, y, z, n, ka); RULE_B_INV(x, y, z, w, n, ke);
164 RULE_B_INV(y, z, w, x, n, kd); RULE_B_INV(z, w, x, y, n, kc);
165 RULE_B_INV(w, x, y, z, n, kb); RULE_B_INV(x, y, z, w, n, ka);
166 RULE_B_INV(y, z, w, x, n, ke); RULE_B_INV(z, w, x, y, n, kd);
167 RULE_A_INV(w, x, y, z, n, kc); RULE_A_INV(x, y, z, w, n, kb);
168 RULE_A_INV(y, z, w, x, n, ka); RULE_A_INV(z, w, x, y, n, ke);
169 RULE_A_INV(w, x, y, z, n, kd); RULE_A_INV(x, y, z, w, n, kc);
170 RULE_A_INV(y, z, w, x, n, kb); RULE_A_INV(z, w, x, y, n, ka);
172 d[0] = ((uint32)w << 16) | (uint32)x;
173 d[1] = ((uint32)y << 16) | (uint32)z;
176 BLKC_TEST(SKIPJACK, skipjack)
178 /*----- That's all, folks -------------------------------------------------*/