| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id$ |
| 4 | * |
| 5 | * Generalized version of KCDSA |
| 6 | * |
| 7 | * (c) 2004 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 | #ifndef CATACOMB_GKCDSA_H |
| 31 | #define CATACOMB_GKCDSA_H |
| 32 | |
| 33 | #ifdef __cplusplus |
| 34 | extern "C" { |
| 35 | #endif |
| 36 | |
| 37 | /*----- Header files ------------------------------------------------------*/ |
| 38 | |
| 39 | #ifndef CATACOMB_GROUP_H |
| 40 | # include "group.h" |
| 41 | #endif |
| 42 | |
| 43 | #ifndef CATACOMB_GHASH_H |
| 44 | # include "ghash.h" |
| 45 | #endif |
| 46 | |
| 47 | #ifndef CATACOMB_GDSA_H |
| 48 | # include "gdsa.h" |
| 49 | #endif |
| 50 | |
| 51 | /*----- Data structures ---------------------------------------------------*/ |
| 52 | |
| 53 | /* --- Careful! --- * |
| 54 | * |
| 55 | * These structures are the same as for DSA. However, the private key @u@ is |
| 56 | * the %$\emph{inverse}$% of the exponent. Do this wrong and the maths will |
| 57 | * fail hopelessly. |
| 58 | */ |
| 59 | |
| 60 | typedef gdsa gkcdsa; |
| 61 | |
| 62 | typedef struct gkcdsa_sig { |
| 63 | octet *r; /* Null means @xmalloc@ me */ |
| 64 | mp *s; |
| 65 | } gkcdsa_sig; |
| 66 | #define GKCDSA_SIG_INIT { 0, 0 } |
| 67 | |
| 68 | /*----- Functions provided ------------------------------------------------*/ |
| 69 | |
| 70 | /* --- @gkcdsa_beginhash@ --- * |
| 71 | * |
| 72 | * Arguments: @const gkcdsa *c@ = pointer to the context structure |
| 73 | * |
| 74 | * Returns: A hashing context for you to hash the message. |
| 75 | * |
| 76 | * Use: Initializes a hash function correctly for you to hash a |
| 77 | * message. Requires @h@, @g@ and @p@. |
| 78 | */ |
| 79 | |
| 80 | extern ghash *gkcdsa_beginhash(const gkcdsa */*c*/); |
| 81 | |
| 82 | /* --- @gkcdsa_endhash@ --- * |
| 83 | * |
| 84 | * Arguments: @const gkcdsa *c@ = pointer to the context structure |
| 85 | * @ghash *h@ = the hashing context |
| 86 | * |
| 87 | * Returns: --- |
| 88 | * |
| 89 | * Use: Does any final thing that KCDSA wants to do when hashing a |
| 90 | * message. (Actually, there's nothing.) The hashing context |
| 91 | * isn't finalized. |
| 92 | */ |
| 93 | |
| 94 | extern void gkcdsa_endhash(const gkcdsa */*c*/, ghash */*h*/); |
| 95 | |
| 96 | /* --- @gkcdsa_sign@ --- * |
| 97 | * |
| 98 | * Arguments: @const gkcdsa *c@ = my context structure |
| 99 | * @gkcdsa_sig *s@ = where to put the signature (initialized) |
| 100 | * @const void *m@ = pointer to message hash |
| 101 | * @mp *k@ = random exponent for this message or null |
| 102 | * |
| 103 | * Returns: --- |
| 104 | * |
| 105 | * Use: Signs a message. Requires @g@, @u@, @h@, and @r@ if @k@ is |
| 106 | * null. This is a better idea than inventing @k@ yourself. |
| 107 | */ |
| 108 | |
| 109 | extern void gkcdsa_sign(const gkcdsa */*c*/, gkcdsa_sig */*s*/, |
| 110 | const void */*m*/, mp */*k*/); |
| 111 | |
| 112 | /* --- @gkcdsa_verify@ --- * |
| 113 | * |
| 114 | * Arguments: @const gkcdsa *c@ = my context structure |
| 115 | * @const gkcdsa_sig *s@ = the signature to verify |
| 116 | * @const void *m@ = pointer to message hash |
| 117 | * |
| 118 | * Returns: Zero if OK, negative on failure. |
| 119 | * |
| 120 | * Use: Checks a signature on a message, Requires @g@, @p@, @h@. |
| 121 | */ |
| 122 | |
| 123 | extern int gkcdsa_verify(const gkcdsa */*c*/, const gkcdsa_sig */*s*/, |
| 124 | const void */*m*/); |
| 125 | |
| 126 | /*----- That's all, folks -------------------------------------------------*/ |
| 127 | |
| 128 | #ifdef __cplusplus |
| 129 | } |
| 130 | #endif |
| 131 | |
| 132 | #endif |