8dd8c294 |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: seal.h,v 1.1 2000/06/17 12:08:34 mdw Exp $ |
4 | * |
5 | * The SEAL pseudo-random function family |
6 | * |
7 | * (c) 2000 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Catacomb. |
13 | * |
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. |
18 | * |
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. |
23 | * |
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, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: seal.h,v $ |
33 | * Revision 1.1 2000/06/17 12:08:34 mdw |
34 | * New cipher. |
35 | * |
36 | */ |
37 | |
38 | /*----- Notes on the SEAL pseudo-random function family -------------------* |
39 | * |
40 | * SEAL is a slightly odd cryptographic primitive. It was designed by Phil |
41 | * Rogaway and Don Coppersmith at IBM, basically as an exercise in producing |
42 | * a really fast symmetric cipher of some kind. They succeeded: SEAL is |
43 | * faster than the much simpler RC4. |
44 | * |
45 | * For each key, it gives you %$2^{32}$% different output streams. This |
46 | * implementation imposes no length limits on the size of output streams and |
47 | * performs careful buffer handling to allow arbitrary amounts of data to be |
48 | * extracted. In practice, extracting more than about 64K is possibly dodgy |
49 | * from a security point of view. |
50 | * |
51 | * SEAL is patented. |
52 | */ |
53 | |
54 | #ifndef CATACOMB_SEAL_H |
55 | #define CATACOMB_SEAL_H |
56 | |
57 | #ifdef __cplusplus |
58 | extern "C" { |
59 | #endif |
60 | |
61 | /*----- Header files ------------------------------------------------------*/ |
62 | |
63 | #ifndef CATACOMB_GCIPHER_H |
64 | # include "gcipher.h" |
65 | #endif |
66 | |
67 | #ifndef CATACOMB_GRAND_H |
68 | # include "grand.h" |
69 | #endif |
70 | |
71 | /*----- Data structures ---------------------------------------------------*/ |
72 | |
73 | #define SEAL_R 256 |
74 | |
75 | typedef struct seal_key { |
76 | octet k[20]; /* Copy of the 160-bit key */ |
77 | uint32 t[512]; /* Substitution table */ |
78 | uint32 s[256]; /* Magic for each iteration */ |
79 | uint32 r[SEAL_R]; /* Magic for the first 64K */ |
80 | } seal_key; |
81 | |
82 | typedef struct seal_ctx { |
83 | seal_key *k; /* Pointer to the key block */ |
84 | uint32 *r, ri; /* Pointer to current magic */ |
85 | uint32 n, l; /* Various indices into things */ |
86 | uint32 a, b, c, d; /* Current chaining variables */ |
87 | uint32 n1, n2, n3, n4; /* Increments for the variables */ |
88 | unsigned i; /* Index into current iteration */ |
89 | octet q[16]; /* Output buffer */ |
90 | unsigned qsz; /* Number of bytes in the buffer */ |
91 | uint32 rbuf[SEAL_R]; /* Buffer for later magic */ |
92 | } seal_ctx; |
93 | |
94 | /*----- Functions provided ------------------------------------------------*/ |
95 | |
96 | /* --- @seal_initkey@ --- * |
97 | * |
98 | * Arguments: @seal_key *k@ = pointer to key block |
99 | * @const void *buf@ = pointer to key material |
100 | * @size_t sz@ = size of the key material |
101 | * |
102 | * Returns: --- |
103 | * |
104 | * Use: Initializes a SEAL key block. The key material may be any |
105 | * size, but if it's not 20 bytes long it's passed to SHA for |
106 | * hashing first. |
107 | */ |
108 | |
109 | extern void seal_initkey(seal_key */*k*/, |
110 | const void */*buf*/, size_t /*sz*/); |
111 | |
112 | /* --- @seal_initctx@ --- * |
113 | * |
114 | * Arguments: @seal_ctx *c@ = pointer to a SEAL context |
115 | * @seal_key *k@ = pointer to a SEAL key |
116 | * @uint32 n@ = integer sequence number |
117 | * |
118 | * Returns: --- |
119 | * |
120 | * Use: Initializes a SEAL context which can be used for random |
121 | * number generation or whatever. |
122 | */ |
123 | |
124 | extern void seal_initctx(seal_ctx */*c*/, seal_key */*k*/, uint32 /*n*/); |
125 | |
126 | /* --- @seal_encrypt@ --- * |
127 | * |
128 | * Arguments: @seal_ctx *c@ = pointer to a SEAL context |
129 | * @const void *src@ = pointer to source data |
130 | * @void *dest@ = pointer to destination data |
131 | * @size_t sz@ = size of the data |
132 | * |
133 | * Returns: --- |
134 | * |
135 | * Use: Encrypts a block of data using SEAL. If @src@ is zero, |
136 | * @dest@ is filled with SEAL output. If @dest@ is zero, the |
137 | * SEAL generator is just spun around for a bit. This shouldn't |
138 | * be necessary, because SEAL isn't RC4. |
139 | */ |
140 | |
141 | extern void seal_encrypt(seal_ctx */*c*/, const void */*src*/, |
142 | void */*dest*/, size_t /*sz*/); |
143 | |
144 | /*----- Generic cipher interface ------------------------------------------*/ |
145 | |
146 | #define SEAL_KEYSZ 20 |
147 | extern const octet seal_keysz[]; |
148 | |
149 | extern const gccipher seal; |
150 | |
151 | /*----- Generic random number generator interface -------------------------*/ |
152 | |
153 | /* --- @seal_rand@ --- * |
154 | * |
155 | * Arguments: @const void *k@ = pointer to key material |
156 | * @size_t sz@ = size of key material |
157 | * @uint32 n@ = sequence number |
158 | * |
159 | * Returns: Pointer to generic random number generator interface. |
160 | * |
161 | * Use: Creates a random number interface wrapper around a SEAL |
162 | * pseudorandom function. |
163 | */ |
164 | |
165 | extern grand *seal_rand(const void */*k*/, size_t /*sz*/, uint32 /*n*/); |
166 | |
167 | /*----- That's all, folks -------------------------------------------------*/ |
168 | |
169 | #ifdef __cplusplus |
170 | } |
171 | #endif |
172 | |
173 | #endif |