3 * $Id: skipjack.c,v 1.3 2000/08/01 00:28:34 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 /*----- Revision history --------------------------------------------------*
32 * $Log: skipjack.c,v $
33 * Revision 1.3 2000/08/01 00:28:34 mdw
34 * Performance improvement: read keys in as 32-bit words and deal them out
37 * Revision 1.2 2000/07/15 20:48:45 mdw
38 * Remove some useless tests in the G function.
40 * Revision 1.1 2000/07/15 15:39:33 mdw
41 * The NSA's Skipjack block cipher.
45 /*----- Header files ------------------------------------------------------*/
47 #include <mLib/bits.h>
52 #include "skipjack-tab.h"
54 /*----- Global variables --------------------------------------------------*/
56 const octet skipjack_keysz
[] = { KSZ_SET
, 10, 0 };
58 /*----- The Skipjack S-box ------------------------------------------------*/
60 static octet f
[256] = SKIPJACK_S
;
62 /*----- Main code ---------------------------------------------------------*/
64 /* --- @skipjack_init@ --- *
66 * Arguments: @skipjack_ctx *k@ = pointer to key block
67 * @const void *buf@ = pointer to key buffer
68 * @size_t sz@ = size of key material
72 * Use: Initializes a Skipjack key buffer. The key buffer must be
73 * exactly 10 bytes long.
76 void skipjack_init(skipjack_ctx
*k
, const void *buf
, size_t sz
)
80 KSZ_ASSERT(skipjack
, sz
);
82 k
->kb
= LOAD32(b
+ 4);
84 k
->kc
= U32((crud
<< 16) | (k
->ka
>> 16));
85 k
->kd
= U32((k
->ka
<< 16) | (k
->kb
>> 16));
86 k
->ke
= U32((k
->kb
<< 16) | crud
);
90 /* --- @skipjack_eblk@, @skipjack_dblk@ --- *
92 * Arguments: @const skipjack_ctx *k@ = pointer to key block
93 * @const uint32 s[2]@ = pointer to source block
94 * @uint32 d[2]@ = pointer to skipjacktination block
98 * Use: Low-level block encryption and decryption.
101 #define G(x, k) do { \
102 octet _x = U8(x >> 8), _y = U8(x); \
103 _x ^= f[_y ^ U8(k >> 24)]; \
104 _y ^= f[_x ^ U8(k >> 16)]; \
105 _x ^= f[_y ^ U8(k >> 8)]; \
106 _y ^= f[_x ^ U8(k >> 0)]; \
107 x = (_x << 8) | _y; \
110 #define RULE_A(w, x, y, z, n, k) do { \
111 G(w, k); z ^= w ^ n++; \
114 #define RULE_B(w, x, y, z, n, k) do { \
115 x ^= w ^ n++; G(w, k); \
118 void skipjack_eblk(const skipjack_ctx
*k
, const uint32
*s
, uint32
*d
)
121 uint16 w
= U16(s
[0] >> 16), x
= U16(s
[0]);
122 uint16 y
= U16(s
[1] >> 16), z
= U16(s
[1]);
123 uint32 ka
= k
->ka
, kb
= k
->kb
, kc
= k
->kc
, kd
= k
->kd
, ke
= k
->ke
;
125 RULE_A(w
, x
, y
, z
, n
, ka
); RULE_A(z
, w
, x
, y
, n
, kb
);
126 RULE_A(y
, z
, w
, x
, n
, kc
); RULE_A(x
, y
, z
, w
, n
, kd
);
127 RULE_A(w
, x
, y
, z
, n
, ke
); RULE_A(z
, w
, x
, y
, n
, ka
);
128 RULE_A(y
, z
, w
, x
, n
, kb
); RULE_A(x
, y
, z
, w
, n
, kc
);
129 RULE_B(w
, x
, y
, z
, n
, kd
); RULE_B(z
, w
, x
, y
, n
, ke
);
130 RULE_B(y
, z
, w
, x
, n
, ka
); RULE_B(x
, y
, z
, w
, n
, kb
);
131 RULE_B(w
, x
, y
, z
, n
, kc
); RULE_B(z
, w
, x
, y
, n
, kd
);
132 RULE_B(y
, z
, w
, x
, n
, ke
); RULE_B(x
, y
, z
, w
, n
, ka
);
133 RULE_A(w
, x
, y
, z
, n
, kb
); RULE_A(z
, w
, x
, y
, n
, kc
);
134 RULE_A(y
, z
, w
, x
, n
, kd
); RULE_A(x
, y
, z
, w
, n
, ke
);
135 RULE_A(w
, x
, y
, z
, n
, ka
); RULE_A(z
, w
, x
, y
, n
, kb
);
136 RULE_A(y
, z
, w
, x
, n
, kc
); RULE_A(x
, y
, z
, w
, n
, kd
);
137 RULE_B(w
, x
, y
, z
, n
, ke
); RULE_B(z
, w
, x
, y
, n
, ka
);
138 RULE_B(y
, z
, w
, x
, n
, kb
); RULE_B(x
, y
, z
, w
, n
, kc
);
139 RULE_B(w
, x
, y
, z
, n
, kd
); RULE_B(z
, w
, x
, y
, n
, ke
);
140 RULE_B(y
, z
, w
, x
, n
, ka
); RULE_B(x
, y
, z
, w
, n
, kb
);
142 d
[0] = ((uint32
)w
<< 16) | (uint32
)x
;
143 d
[1] = ((uint32
)y
<< 16) | (uint32
)z
;
146 #define G_INV(x, k) do { \
147 octet _x = U8(x >> 8), _y = U8(x); \
148 _y ^= f[_x ^ U8(k >> 0)]; \
149 _x ^= f[_y ^ U8(k >> 8)]; \
150 _y ^= f[_x ^ U8(k >> 16)]; \
151 _x ^= f[_y ^ U8(k >> 24)]; \
152 x = (_x << 8) | _y; \
155 #define RULE_A_INV(w, x, y, z, n, i) do { \
156 w ^= x ^ --n; G_INV(x, i); \
159 #define RULE_B_INV(w, x, y, z, n, i) do { \
160 G_INV(x, i); y ^= x ^ --n; \
163 void skipjack_dblk(const skipjack_ctx
*k
, const uint32
*s
, uint32
*d
)
166 uint16 w
= U16(s
[0] >> 16), x
= U16(s
[0]);
167 uint16 y
= U16(s
[1] >> 16), z
= U16(s
[1]);
168 uint32 ka
= k
->ka
, kb
= k
->kb
, kc
= k
->kc
, kd
= k
->kd
, ke
= k
->ke
;
170 RULE_B_INV(w
, x
, y
, z
, n
, kb
); RULE_B_INV(x
, y
, z
, w
, n
, ka
);
171 RULE_B_INV(y
, z
, w
, x
, n
, ke
); RULE_B_INV(z
, w
, x
, y
, n
, kd
);
172 RULE_B_INV(w
, x
, y
, z
, n
, kc
); RULE_B_INV(x
, y
, z
, w
, n
, kb
);
173 RULE_B_INV(y
, z
, w
, x
, n
, ka
); RULE_B_INV(z
, w
, x
, y
, n
, ke
);
174 RULE_A_INV(w
, x
, y
, z
, n
, kd
); RULE_A_INV(x
, y
, z
, w
, n
, kc
);
175 RULE_A_INV(y
, z
, w
, x
, n
, kb
); RULE_A_INV(z
, w
, x
, y
, n
, ka
);
176 RULE_A_INV(w
, x
, y
, z
, n
, ke
); RULE_A_INV(x
, y
, z
, w
, n
, kd
);
177 RULE_A_INV(y
, z
, w
, x
, n
, kc
); RULE_A_INV(z
, w
, x
, y
, n
, kb
);
178 RULE_B_INV(w
, x
, y
, z
, n
, ka
); RULE_B_INV(x
, y
, z
, w
, n
, ke
);
179 RULE_B_INV(y
, z
, w
, x
, n
, kd
); RULE_B_INV(z
, w
, x
, y
, n
, kc
);
180 RULE_B_INV(w
, x
, y
, z
, n
, kb
); RULE_B_INV(x
, y
, z
, w
, n
, ka
);
181 RULE_B_INV(y
, z
, w
, x
, n
, ke
); RULE_B_INV(z
, w
, x
, y
, n
, kd
);
182 RULE_A_INV(w
, x
, y
, z
, n
, kc
); RULE_A_INV(x
, y
, z
, w
, n
, kb
);
183 RULE_A_INV(y
, z
, w
, x
, n
, ka
); RULE_A_INV(z
, w
, x
, y
, n
, ke
);
184 RULE_A_INV(w
, x
, y
, z
, n
, kd
); RULE_A_INV(x
, y
, z
, w
, n
, kc
);
185 RULE_A_INV(y
, z
, w
, x
, n
, kb
); RULE_A_INV(z
, w
, x
, y
, n
, ka
);
187 d
[0] = ((uint32
)w
<< 16) | (uint32
)x
;
188 d
[1] = ((uint32
)y
<< 16) | (uint32
)z
;
191 BLKC_TEST(SKIPJACK
, skipjack
)
193 /*----- That's all, folks -------------------------------------------------*/