3 * The Skipjack 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 ------------------------------------------------------*/
30 #include <mLib/bits.h>
36 /*----- Global variables --------------------------------------------------*/
38 const octet skipjack_keysz
[] = { KSZ_SET
, 10, 0 };
40 /*----- The Skipjack S-box ------------------------------------------------*/
42 extern const octet skipjack_s
[256];
44 /*----- Main code ---------------------------------------------------------*/
46 /* --- @skipjack_init@ --- *
48 * Arguments: @skipjack_ctx *k@ = pointer to key block
49 * @const void *buf@ = pointer to key buffer
50 * @size_t sz@ = size of key material
54 * Use: Initializes a Skipjack key buffer. The key buffer must be
55 * exactly 10 bytes long.
58 void skipjack_init(skipjack_ctx
*k
, const void *buf
, size_t sz
)
62 KSZ_ASSERT(skipjack
, sz
);
64 k
->kb
= LOAD32(b
+ 4);
66 k
->kc
= U32((crud
<< 16) | (k
->ka
>> 16));
67 k
->kd
= U32((k
->ka
<< 16) | (k
->kb
>> 16));
68 k
->ke
= U32((k
->kb
<< 16) | crud
);
72 /* --- @skipjack_eblk@, @skipjack_dblk@ --- *
74 * Arguments: @const skipjack_ctx *k@ = pointer to key block
75 * @const uint32 s[2]@ = pointer to source block
76 * @uint32 d[2]@ = pointer to skipjacktination block
80 * Use: Low-level block encryption and decryption.
83 #define G(x, k) do { \
84 octet _x = U8(x >> 8), _y = U8(x); \
85 _x ^= skipjack_s[_y ^ U8(k >> 24)]; \
86 _y ^= skipjack_s[_x ^ U8(k >> 16)]; \
87 _x ^= skipjack_s[_y ^ U8(k >> 8)]; \
88 _y ^= skipjack_s[_x ^ U8(k >> 0)]; \
92 #define RULE_A(w, x, y, z, n, k) do { \
93 G(w, k); z ^= w ^ n++; \
96 #define RULE_B(w, x, y, z, n, k) do { \
97 x ^= w ^ n++; G(w, k); \
100 void skipjack_eblk(const skipjack_ctx
*k
, const uint32
*s
, uint32
*d
)
103 uint16 w
= U16(s
[0] >> 16), x
= U16(s
[0]);
104 uint16 y
= U16(s
[1] >> 16), z
= U16(s
[1]);
105 uint32 ka
= k
->ka
, kb
= k
->kb
, kc
= k
->kc
, kd
= k
->kd
, ke
= k
->ke
;
107 RULE_A(w
, x
, y
, z
, n
, ka
); RULE_A(z
, w
, x
, y
, n
, kb
);
108 RULE_A(y
, z
, w
, x
, n
, kc
); RULE_A(x
, y
, z
, w
, n
, kd
);
109 RULE_A(w
, x
, y
, z
, n
, ke
); RULE_A(z
, w
, x
, y
, n
, ka
);
110 RULE_A(y
, z
, w
, x
, n
, kb
); RULE_A(x
, y
, z
, w
, n
, kc
);
111 RULE_B(w
, x
, y
, z
, n
, kd
); RULE_B(z
, w
, x
, y
, n
, ke
);
112 RULE_B(y
, z
, w
, x
, n
, ka
); RULE_B(x
, y
, z
, w
, n
, kb
);
113 RULE_B(w
, x
, y
, z
, n
, kc
); RULE_B(z
, w
, x
, y
, n
, kd
);
114 RULE_B(y
, z
, w
, x
, n
, ke
); RULE_B(x
, y
, z
, w
, n
, ka
);
115 RULE_A(w
, x
, y
, z
, n
, kb
); RULE_A(z
, w
, x
, y
, n
, kc
);
116 RULE_A(y
, z
, w
, x
, n
, kd
); RULE_A(x
, y
, z
, w
, n
, ke
);
117 RULE_A(w
, x
, y
, z
, n
, ka
); RULE_A(z
, w
, x
, y
, n
, kb
);
118 RULE_A(y
, z
, w
, x
, n
, kc
); RULE_A(x
, y
, z
, w
, n
, kd
);
119 RULE_B(w
, x
, y
, z
, n
, ke
); RULE_B(z
, w
, x
, y
, n
, ka
);
120 RULE_B(y
, z
, w
, x
, n
, kb
); RULE_B(x
, y
, z
, w
, n
, kc
);
121 RULE_B(w
, x
, y
, z
, n
, kd
); RULE_B(z
, w
, x
, y
, n
, ke
);
122 RULE_B(y
, z
, w
, x
, n
, ka
); RULE_B(x
, y
, z
, w
, n
, kb
);
124 d
[0] = ((uint32
)w
<< 16) | (uint32
)x
;
125 d
[1] = ((uint32
)y
<< 16) | (uint32
)z
;
128 #define G_INV(x, k) do { \
129 octet _x = U8(x >> 8), _y = U8(x); \
130 _y ^= skipjack_s[_x ^ U8(k >> 0)]; \
131 _x ^= skipjack_s[_y ^ U8(k >> 8)]; \
132 _y ^= skipjack_s[_x ^ U8(k >> 16)]; \
133 _x ^= skipjack_s[_y ^ U8(k >> 24)]; \
134 x = (_x << 8) | _y; \
137 #define RULE_A_INV(w, x, y, z, n, i) do { \
138 w ^= x ^ --n; G_INV(x, i); \
141 #define RULE_B_INV(w, x, y, z, n, i) do { \
142 G_INV(x, i); y ^= x ^ --n; \
145 void skipjack_dblk(const skipjack_ctx
*k
, const uint32
*s
, uint32
*d
)
148 uint16 w
= U16(s
[0] >> 16), x
= U16(s
[0]);
149 uint16 y
= U16(s
[1] >> 16), z
= U16(s
[1]);
150 uint32 ka
= k
->ka
, kb
= k
->kb
, kc
= k
->kc
, kd
= k
->kd
, ke
= k
->ke
;
152 RULE_B_INV(w
, x
, y
, z
, n
, kb
); RULE_B_INV(x
, y
, z
, w
, n
, ka
);
153 RULE_B_INV(y
, z
, w
, x
, n
, ke
); RULE_B_INV(z
, w
, x
, y
, n
, kd
);
154 RULE_B_INV(w
, x
, y
, z
, n
, kc
); RULE_B_INV(x
, y
, z
, w
, n
, kb
);
155 RULE_B_INV(y
, z
, w
, x
, n
, ka
); RULE_B_INV(z
, w
, x
, y
, n
, ke
);
156 RULE_A_INV(w
, x
, y
, z
, n
, kd
); RULE_A_INV(x
, y
, z
, w
, n
, kc
);
157 RULE_A_INV(y
, z
, w
, x
, n
, kb
); RULE_A_INV(z
, w
, x
, y
, n
, ka
);
158 RULE_A_INV(w
, x
, y
, z
, n
, ke
); RULE_A_INV(x
, y
, z
, w
, n
, kd
);
159 RULE_A_INV(y
, z
, w
, x
, n
, kc
); RULE_A_INV(z
, w
, x
, y
, n
, kb
);
160 RULE_B_INV(w
, x
, y
, z
, n
, ka
); RULE_B_INV(x
, y
, z
, w
, n
, ke
);
161 RULE_B_INV(y
, z
, w
, x
, n
, kd
); RULE_B_INV(z
, w
, x
, y
, n
, kc
);
162 RULE_B_INV(w
, x
, y
, z
, n
, kb
); RULE_B_INV(x
, y
, z
, w
, n
, ka
);
163 RULE_B_INV(y
, z
, w
, x
, n
, ke
); RULE_B_INV(z
, w
, x
, y
, n
, kd
);
164 RULE_A_INV(w
, x
, y
, z
, n
, kc
); RULE_A_INV(x
, y
, z
, w
, n
, kb
);
165 RULE_A_INV(y
, z
, w
, x
, n
, ka
); RULE_A_INV(z
, w
, x
, y
, n
, ke
);
166 RULE_A_INV(w
, x
, y
, z
, n
, kd
); RULE_A_INV(x
, y
, z
, w
, n
, kc
);
167 RULE_A_INV(y
, z
, w
, x
, n
, kb
); RULE_A_INV(z
, w
, x
, y
, n
, ka
);
169 d
[0] = ((uint32
)w
<< 16) | (uint32
)x
;
170 d
[1] = ((uint32
)y
<< 16) | (uint32
)z
;
173 BLKC_TEST(SKIPJACK
, skipjack
)
175 /*----- That's all, folks -------------------------------------------------*/