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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: dsa.h,v 1.8 2001/02/03 16:08:24 mdw Exp $ |
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4 | * |
5 | * Digital Signature Algorithm |
6 | * |
7 | * (c) 1999 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: dsa.h,v $ |
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33 | * Revision 1.8 2001/02/03 16:08:24 mdw |
34 | * Add consistency checking for public keys. |
35 | * |
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36 | * Revision 1.7 2000/07/29 09:59:44 mdw |
37 | * Share data structures with Diffie-Hellman stuff. |
38 | * |
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39 | * Revision 1.6 2000/07/01 11:20:51 mdw |
40 | * New functions for freeing public and private keys. |
41 | * |
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42 | * Revision 1.5 2000/06/17 10:53:42 mdw |
43 | * Minor changes for key fetching. Typesetting fixes. |
44 | * |
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45 | * Revision 1.4 1999/12/22 15:52:44 mdw |
46 | * Reworking for new prime-search system. |
47 | * |
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48 | * Revision 1.3 1999/12/10 23:29:48 mdw |
49 | * Change header file guard names. |
50 | * |
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51 | * Revision 1.2 1999/11/20 22:23:48 mdw |
52 | * Allow event handler to abort the search process. |
53 | * |
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54 | * Revision 1.1 1999/11/19 19:28:00 mdw |
55 | * Implementation of the Digital Signature Algorithm. |
56 | * |
57 | */ |
58 | |
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59 | #ifndef CATACOMB_DSA_H |
60 | #define CATACOMB_DSA_H |
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61 | |
62 | #ifdef __cplusplus |
63 | extern "C" { |
64 | #endif |
65 | |
66 | /*----- Notes on the Digital Signature Algorithm --------------------------* |
67 | * |
68 | * The Digital Signature Algorithm was designed by the NSA for US Government |
69 | * use. It's defined in FIPS 186-1. Whether it's covered by patents is |
70 | * under dispute, although it looks relatively clear. It produces compact |
71 | * signatures, and is relatively easy to compute. It seems strong, if |
72 | * appropriate parameters are chosen. |
73 | */ |
74 | |
75 | /*----- Header files ------------------------------------------------------*/ |
76 | |
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77 | #ifndef CATACOMB_DH_H |
78 | # include "dh.h" |
79 | #endif |
80 | |
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81 | #ifndef CATACOMB_KEY_H |
82 | # include "key.h" |
83 | #endif |
84 | |
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85 | #ifndef CATACOMB_KEYCHECK_H |
86 | # include "keycheck.h" |
87 | #endif |
88 | |
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89 | #ifndef CATACOMB_MP_H |
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90 | # include "mp.h" |
91 | #endif |
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92 | |
93 | #ifndef CATACOMB_PGEN_H |
94 | # include "pgen.h" |
95 | #endif |
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96 | |
97 | /*----- Data structures ---------------------------------------------------*/ |
98 | |
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99 | /* --- The parameters and keys are the same as for Diffie-Hellman --- */ |
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100 | |
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101 | typedef dh_param dsa_param; |
102 | typedef dh_pub dsa_pub; |
103 | typedef dh_priv dsa_priv; |
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104 | |
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105 | /* --- DSA key seed structure --- */ |
106 | |
107 | typedef struct dsa_seed { |
108 | void *p; /* Pointer to seed material */ |
109 | size_t sz; /* Size of seed material */ |
110 | unsigned count; /* Iterations to find @p@ */ |
111 | } dsa_seed; |
112 | |
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113 | /* --- DSA signature structure --- * |
114 | * |
115 | * This is the recommended structure for a DSA signature. The actual signing |
116 | * function can cope with arbitrary-sized objects given appropriate |
117 | * parameters, however. |
118 | */ |
119 | |
120 | #define DSA_SIGLEN 20 |
121 | |
122 | typedef struct dsa_sig { |
123 | octet r[DSA_SIGLEN]; /* 160-bit @r@ value */ |
124 | octet s[DSA_SIGLEN]; /* 160-bit @s@ value */ |
125 | } dsa_sig; |
126 | |
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127 | /*----- Key fetching ------------------------------------------------------*/ |
128 | |
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129 | #define dsa_paramfetch dh_paramfetch |
130 | #define dsa_pubfetch dh_pubfetch |
131 | #define dsa_privfetch dh_privfetch |
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132 | |
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133 | #define DSA_PARAMFETCHSZ DH_PARAMFETCHSZ |
134 | #define DSA_PUBFETCHSZ DH_PUBFETCHSZ |
135 | #define DSA_PRIVFETCHSZ DH_PRIVFETCHSZ |
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136 | |
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137 | #define dsa_paramfree dh_paramfree |
138 | #define dsa_pubfree dh_pubfree |
139 | #define dsa_privfree dh_privfree |
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140 | |
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141 | /*----- DSA stepper -------------------------------------------------------*/ |
142 | |
143 | typedef struct dsa_stepctx { |
144 | |
145 | /* --- To be initialized by the client --- */ |
146 | |
147 | grand *r; /* Random number generator */ |
148 | mp *q; /* Force @p@ to be a multiple */ |
149 | size_t bits; /* Number of bits in the result */ |
150 | unsigned or; /* OR mask for low order bits */ |
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151 | unsigned count; /* Counts the number of steps made */ |
152 | void *seedbuf; /* Pointer to seed buffer */ |
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153 | } dsa_stepctx; |
154 | |
155 | /* --- @dsa_step@ --- * |
156 | * |
157 | * The stepper chooses random integers, ensures that they are a multiple of |
158 | * @q@ (if specified), sets the low-order bits, and then tests for |
159 | * divisibility by small primes. |
160 | */ |
161 | |
162 | extern int dsa_step(int /*rq*/, pgen_event */*ev*/, void */*p*/); |
163 | |
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164 | /*----- Functions provided ------------------------------------------------*/ |
165 | |
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166 | /* --- @dsa_gen@ --- * |
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167 | * |
168 | * Arguments: @dsa_param *dp@ = where to store parameters |
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169 | * @unsigned ql@ = length of @q@ in bits |
170 | * @unsigned pl@ = length of @p@ in bits |
171 | * @unsigned steps@ = number of steps to find @q@ |
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172 | * @const void *k@ = pointer to key material |
173 | * @size_t sz@ = size of key material |
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174 | * @dsa_seed *sd@ = optional pointer for output seed information |
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175 | * @pgen_proc *event@ = event handler function |
176 | * @void *ectx@ = argument for event handler |
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177 | * |
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178 | * Returns: @PGEN_DONE@ if everything worked ok; @PGEN_ABORT@ otherwise. |
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179 | * |
180 | * Use: Generates the DSA shared parameters from a given seed value. |
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181 | * This can take quite a long time. |
182 | * |
183 | * The algorithm used is a compatible extension of the method |
184 | * described in the DSA standard, FIPS 186. The standard |
185 | * requires that %$q$% be 160 bits in size (i.e., @ql == 160@) |
186 | * and that the length of %$p$% be %$L = 512 + 64l$% for some |
187 | * %$l$%. Neither limitation applies to this implementation. |
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188 | */ |
189 | |
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190 | extern int dsa_gen(dsa_param */*dp*/, unsigned /*ql*/, unsigned /*pl*/, |
191 | unsigned /*steps*/, const void */*k*/, size_t /*sz*/, |
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192 | dsa_seed */*sd*/, pgen_proc */*event*/, void */*ectx*/); |
193 | |
194 | /* --- @dsa_checkparam@ --- * |
195 | * |
196 | * Arguments: @keycheck *kc@ = keycheck state |
197 | * @const dsa_param *dp@ = pointer to the parameter set |
198 | * @const dsa_seed *ds@ = pointer to seed information |
199 | * |
200 | * Returns: Zero if all OK, or return status from function. |
201 | * |
202 | * Use: Checks a set of DSA parameters for consistency and security. |
203 | */ |
204 | |
205 | extern int dsa_checkparam(keycheck */*kc*/, const dsa_param */*dp*/, |
206 | const dsa_seed */*ds*/); |
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207 | |
208 | /* --- @dsa_mksig@ --- * |
209 | * |
210 | * Arguments: @const dsa_param *dp@ = pointer to DSA parameters |
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211 | * @mp *a@ = secret signing key |
212 | * @mp *m@ = message to be signed |
213 | * @mp *k@ = random data |
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214 | * @mp **rr, **ss@ = where to put output parameters |
215 | * |
216 | * Returns: --- |
217 | * |
218 | * Use: Computes a DSA signature of a message. |
219 | */ |
220 | |
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221 | extern void dsa_mksig(const dsa_param */*dp*/, mp */*a*/, |
222 | mp */*m*/, mp */*k*/, |
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223 | mp **/*rr*/, mp **/*ss*/); |
224 | |
225 | /* --- @dsa_sign@ --- * |
226 | * |
227 | * Arguments: @dsa_param *dp@ = pointer to DSA parameters |
228 | * @mp *a@ = pointer to secret signing key |
229 | * @const void *m@ = pointer to message |
230 | * @size_t msz@ = size of the message |
231 | * @const void *k@ = secret random data for securing signature |
232 | * @size_t ksz@ = size of secret data |
233 | * @void *r@ = pointer to output space for @r@ |
234 | * @size_t rsz@ = size of output space for @r@ |
235 | * @void *s@ = pointer to output space for @s@ |
236 | * @size_t ssz@ = size of output space for @s@ |
237 | * |
238 | * Returns: --- |
239 | * |
240 | * Use: Signs a message, storing the results in a big-endian binary |
241 | * form. |
242 | */ |
243 | |
244 | extern void dsa_sign(dsa_param */*dp*/, mp */*a*/, |
245 | const void */*m*/, size_t /*msz*/, |
246 | const void */*k*/, size_t /*ksz*/, |
247 | void */*r*/, size_t /*rsz*/, |
248 | void */*s*/, size_t /*ssz*/); |
249 | |
250 | /* --- @dsa_vrfy@ --- * |
251 | * |
252 | * Arguments: @const dsa_param *dp@ = pointer to DSA parameters |
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253 | * @mp *y@ = public verification key |
254 | * @mp *m@ = message which was signed |
255 | * @mp *r, *s@ = the signature |
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256 | * |
257 | * Returns: Zero if the signature is a forgery, nonzero if it's valid. |
258 | * |
259 | * Use: Verifies a DSA digital signature. |
260 | */ |
261 | |
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262 | extern int dsa_vrfy(const dsa_param */*dp*/, mp */*y*/, |
263 | mp */*m*/, mp */*r*/, mp */*s*/); |
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264 | |
265 | /* --- @dsa_verify@ --- * |
266 | * |
267 | * Arguments: @const dsa_param *dp@ = pointer to DSA parameters |
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268 | * @mp *y@ = public verification key |
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269 | * @const void *m@ = pointer to message block |
270 | * @size_t msz@ = size of message block |
271 | * @const void *r@ = pointer to @r@ signature half |
272 | * @size_t rsz@ = size of @r@ |
273 | * @const void *s@ = pointer to @s@ signature half |
274 | * @size_t ssz@ = size of @s@ |
275 | * |
276 | * Returns: Zero if the signature is a forgery, nonzero if it's valid. |
277 | * |
278 | * Use: Verifies a DSA digital signature. |
279 | */ |
280 | |
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281 | extern int dsa_verify(const dsa_param */*dp*/, mp */*y*/, |
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282 | const void */*m*/, size_t /*msz*/, |
283 | const void */*r*/, size_t /*rsz*/, |
284 | const void */*s*/, size_t /*ssz*/); |
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285 | |
286 | /*----- That's all, folks -------------------------------------------------*/ |
287 | |
288 | #ifdef __cplusplus |
289 | } |
290 | #endif |
291 | |
292 | #endif |