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1 | /* -*-c-*- |
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2 | * |
3 | * Generalized version of KCDSA |
4 | * |
5 | * (c) 2004 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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9 | * |
10 | * This file is part of Catacomb. |
11 | * |
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. |
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16 | * |
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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. |
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21 | * |
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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, |
25 | * MA 02111-1307, USA. |
26 | */ |
27 | |
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28 | #ifndef CATACOMB_GKCDSA_H |
29 | #define CATACOMB_GKCDSA_H |
30 | |
31 | #ifdef __cplusplus |
32 | extern "C" { |
33 | #endif |
34 | |
35 | /*----- Header files ------------------------------------------------------*/ |
36 | |
37 | #ifndef CATACOMB_GROUP_H |
38 | # include "group.h" |
39 | #endif |
40 | |
41 | #ifndef CATACOMB_GHASH_H |
42 | # include "ghash.h" |
43 | #endif |
44 | |
45 | #ifndef CATACOMB_GDSA_H |
46 | # include "gdsa.h" |
47 | #endif |
48 | |
49 | /*----- Data structures ---------------------------------------------------*/ |
50 | |
51 | /* --- Careful! --- * |
52 | * |
53 | * These structures are the same as for DSA. However, the private key @u@ is |
54 | * the %$\emph{inverse}$% of the exponent. Do this wrong and the maths will |
55 | * fail hopelessly. |
56 | */ |
57 | |
58 | typedef gdsa gkcdsa; |
59 | |
60 | typedef struct gkcdsa_sig { |
61 | octet *r; /* Null means @xmalloc@ me */ |
62 | mp *s; |
63 | } gkcdsa_sig; |
64 | #define GKCDSA_SIG_INIT { 0, 0 } |
65 | |
66 | /*----- Functions provided ------------------------------------------------*/ |
67 | |
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68 | /* --- @gkcdsa_beginhash@ --- * |
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69 | * |
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70 | * Arguments: @const gkcdsa *c@ = pointer to the context structure |
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71 | * |
72 | * Returns: A hashing context for you to hash the message. |
73 | * |
74 | * Use: Initializes a hash function correctly for you to hash a |
75 | * message. Requires @h@, @g@ and @p@. |
76 | */ |
77 | |
78 | extern ghash *gkcdsa_beginhash(const gkcdsa */*c*/); |
79 | |
80 | /* --- @gkcdsa_endhash@ --- * |
81 | * |
82 | * Arguments: @const gkcdsa *c@ = pointer to the context structure |
83 | * @ghash *h@ = the hashing context |
84 | * |
85 | * Returns: --- |
86 | * |
87 | * Use: Does any final thing that KCDSA wants to do when hashing a |
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88 | * message. (Actually, there's nothing.) The hashing context |
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89 | * isn't finalized. |
90 | */ |
91 | |
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92 | extern void gkcdsa_endhash(const gkcdsa */*c*/, ghash */*h*/); |
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93 | |
94 | /* --- @gkcdsa_sign@ --- * |
95 | * |
96 | * Arguments: @const gkcdsa *c@ = my context structure |
97 | * @gkcdsa_sig *s@ = where to put the signature (initialized) |
98 | * @const void *m@ = pointer to message hash |
99 | * @mp *k@ = random exponent for this message or null |
100 | * |
101 | * Returns: --- |
102 | * |
103 | * Use: Signs a message. Requires @g@, @u@, @h@, and @r@ if @k@ is |
104 | * null. This is a better idea than inventing @k@ yourself. |
105 | */ |
106 | |
107 | extern void gkcdsa_sign(const gkcdsa */*c*/, gkcdsa_sig */*s*/, |
108 | const void */*m*/, mp */*k*/); |
109 | |
110 | /* --- @gkcdsa_verify@ --- * |
111 | * |
112 | * Arguments: @const gkcdsa *c@ = my context structure |
113 | * @const gkcdsa_sig *s@ = the signature to verify |
114 | * @const void *m@ = pointer to message hash |
115 | * |
116 | * Returns: Zero if OK, negative on failure. |
117 | * |
118 | * Use: Checks a signature on a message, Requires @g@, @p@, @h@. |
119 | */ |
120 | |
121 | extern int gkcdsa_verify(const gkcdsa */*c*/, const gkcdsa_sig */*s*/, |
122 | const void */*m*/); |
123 | |
124 | /*----- That's all, folks -------------------------------------------------*/ |
125 | |
126 | #ifdef __cplusplus |
127 | } |
128 | #endif |
129 | |
130 | #endif |