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1 | /* -*-c-*- |
2 | * |
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3 | * $Id$ |
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4 | * |
5 | * Generalized version of KCDSA |
6 | * |
7 | * (c) 2004 Straylight/Edgeware |
8 | */ |
9 | |
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10 | /*----- Licensing notice --------------------------------------------------* |
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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. |
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18 | * |
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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. |
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23 | * |
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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 | |
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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 | |
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70 | /* --- @gkcdsa_beginhash@ --- * |
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71 | * |
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72 | * Arguments: @const gkcdsa *c@ = pointer to the context structure |
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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 |
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90 | * message. (Actually, there's nothing.) The hashing context |
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91 | * isn't finalized. |
92 | */ |
93 | |
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94 | extern void gkcdsa_endhash(const gkcdsa */*c*/, ghash */*h*/); |
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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 |