| 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 |