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8b810a45 | 1 | /* -*-c-*- |
2 | * | |
b817bfc6 | 3 | * $Id: dsa.h,v 1.9 2004/04/08 01:36:15 mdw Exp $ |
8b810a45 | 4 | * |
5 | * Digital Signature Algorithm | |
6 | * | |
7 | * (c) 1999 Straylight/Edgeware | |
8 | */ | |
9 | ||
45c0fd36 | 10 | /*----- Licensing notice --------------------------------------------------* |
8b810a45 | 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. | |
45c0fd36 | 18 | * |
8b810a45 | 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. | |
45c0fd36 | 23 | * |
8b810a45 | 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 | ||
b3f05084 | 30 | #ifndef CATACOMB_DSA_H |
31 | #define CATACOMB_DSA_H | |
8b810a45 | 32 | |
33 | #ifdef __cplusplus | |
34 | extern "C" { | |
35 | #endif | |
36 | ||
37 | /*----- Notes on the Digital Signature Algorithm --------------------------* | |
38 | * | |
39 | * The Digital Signature Algorithm was designed by the NSA for US Government | |
40 | * use. It's defined in FIPS 186-1. Whether it's covered by patents is | |
41 | * under dispute, although it looks relatively clear. It produces compact | |
42 | * signatures, and is relatively easy to compute. It seems strong, if | |
43 | * appropriate parameters are chosen. | |
44 | */ | |
45 | ||
46 | /*----- Header files ------------------------------------------------------*/ | |
47 | ||
827e6c99 | 48 | #ifndef CATACOMB_DH_H |
49 | # include "dh.h" | |
50 | #endif | |
51 | ||
80a2ff16 | 52 | #ifndef CATACOMB_KEY_H |
53 | # include "key.h" | |
54 | #endif | |
55 | ||
600127f0 | 56 | #ifndef CATACOMB_KEYCHECK_H |
57 | # include "keycheck.h" | |
58 | #endif | |
59 | ||
b3f05084 | 60 | #ifndef CATACOMB_MP_H |
8b810a45 | 61 | # include "mp.h" |
62 | #endif | |
45c0fd36 | 63 | |
b04a7659 | 64 | #ifndef CATACOMB_PGEN_H |
65 | # include "pgen.h" | |
66 | #endif | |
8b810a45 | 67 | |
68 | /*----- Data structures ---------------------------------------------------*/ | |
69 | ||
827e6c99 | 70 | /* --- The parameters and keys are the same as for Diffie-Hellman --- */ |
80a2ff16 | 71 | |
827e6c99 | 72 | typedef dh_param dsa_param; |
73 | typedef dh_pub dsa_pub; | |
74 | typedef dh_priv dsa_priv; | |
80a2ff16 | 75 | |
600127f0 | 76 | /* --- DSA key seed structure --- */ |
77 | ||
78 | typedef struct dsa_seed { | |
79 | void *p; /* Pointer to seed material */ | |
80 | size_t sz; /* Size of seed material */ | |
81 | unsigned count; /* Iterations to find @p@ */ | |
82 | } dsa_seed; | |
83 | ||
8b810a45 | 84 | /* --- DSA signature structure --- * |
85 | * | |
86 | * This is the recommended structure for a DSA signature. The actual signing | |
87 | * function can cope with arbitrary-sized objects given appropriate | |
88 | * parameters, however. | |
89 | */ | |
90 | ||
91 | #define DSA_SIGLEN 20 | |
92 | ||
93 | typedef struct dsa_sig { | |
94 | octet r[DSA_SIGLEN]; /* 160-bit @r@ value */ | |
95 | octet s[DSA_SIGLEN]; /* 160-bit @s@ value */ | |
96 | } dsa_sig; | |
97 | ||
80a2ff16 | 98 | /*----- Key fetching ------------------------------------------------------*/ |
99 | ||
827e6c99 | 100 | #define dsa_paramfetch dh_paramfetch |
101 | #define dsa_pubfetch dh_pubfetch | |
102 | #define dsa_privfetch dh_privfetch | |
80a2ff16 | 103 | |
827e6c99 | 104 | #define DSA_PARAMFETCHSZ DH_PARAMFETCHSZ |
105 | #define DSA_PUBFETCHSZ DH_PUBFETCHSZ | |
106 | #define DSA_PRIVFETCHSZ DH_PRIVFETCHSZ | |
b92da8eb | 107 | |
827e6c99 | 108 | #define dsa_paramfree dh_paramfree |
109 | #define dsa_pubfree dh_pubfree | |
110 | #define dsa_privfree dh_privfree | |
b92da8eb | 111 | |
b04a7659 | 112 | /*----- DSA stepper -------------------------------------------------------*/ |
113 | ||
114 | typedef struct dsa_stepctx { | |
115 | ||
116 | /* --- To be initialized by the client --- */ | |
117 | ||
118 | grand *r; /* Random number generator */ | |
119 | mp *q; /* Force @p@ to be a multiple */ | |
120 | size_t bits; /* Number of bits in the result */ | |
121 | unsigned or; /* OR mask for low order bits */ | |
600127f0 | 122 | unsigned count; /* Counts the number of steps made */ |
123 | void *seedbuf; /* Pointer to seed buffer */ | |
b04a7659 | 124 | } dsa_stepctx; |
125 | ||
126 | /* --- @dsa_step@ --- * | |
127 | * | |
128 | * The stepper chooses random integers, ensures that they are a multiple of | |
129 | * @q@ (if specified), sets the low-order bits, and then tests for | |
130 | * divisibility by small primes. | |
131 | */ | |
132 | ||
ab6ce636 | 133 | extern pgen_proc dsa_step; |
b04a7659 | 134 | |
8b810a45 | 135 | /*----- Functions provided ------------------------------------------------*/ |
136 | ||
827e6c99 | 137 | /* --- @dsa_gen@ --- * |
8b810a45 | 138 | * |
139 | * Arguments: @dsa_param *dp@ = where to store parameters | |
b04a7659 | 140 | * @unsigned ql@ = length of @q@ in bits |
141 | * @unsigned pl@ = length of @p@ in bits | |
142 | * @unsigned steps@ = number of steps to find @q@ | |
8b810a45 | 143 | * @const void *k@ = pointer to key material |
144 | * @size_t sz@ = size of key material | |
600127f0 | 145 | * @dsa_seed *sd@ = optional pointer for output seed information |
b04a7659 | 146 | * @pgen_proc *event@ = event handler function |
147 | * @void *ectx@ = argument for event handler | |
8b810a45 | 148 | * |
b04a7659 | 149 | * Returns: @PGEN_DONE@ if everything worked ok; @PGEN_ABORT@ otherwise. |
8b810a45 | 150 | * |
151 | * Use: Generates the DSA shared parameters from a given seed value. | |
b04a7659 | 152 | * This can take quite a long time. |
153 | * | |
154 | * The algorithm used is a compatible extension of the method | |
155 | * described in the DSA standard, FIPS 186. The standard | |
156 | * requires that %$q$% be 160 bits in size (i.e., @ql == 160@) | |
157 | * and that the length of %$p$% be %$L = 512 + 64l$% for some | |
158 | * %$l$%. Neither limitation applies to this implementation. | |
8b810a45 | 159 | */ |
160 | ||
827e6c99 | 161 | extern int dsa_gen(dsa_param */*dp*/, unsigned /*ql*/, unsigned /*pl*/, |
162 | unsigned /*steps*/, const void */*k*/, size_t /*sz*/, | |
600127f0 | 163 | dsa_seed */*sd*/, pgen_proc */*event*/, void */*ectx*/); |
164 | ||
165 | /* --- @dsa_checkparam@ --- * | |
166 | * | |
167 | * Arguments: @keycheck *kc@ = keycheck state | |
168 | * @const dsa_param *dp@ = pointer to the parameter set | |
169 | * @const dsa_seed *ds@ = pointer to seed information | |
170 | * | |
171 | * Returns: Zero if all OK, or return status from function. | |
172 | * | |
173 | * Use: Checks a set of DSA parameters for consistency and security. | |
174 | */ | |
175 | ||
176 | extern int dsa_checkparam(keycheck */*kc*/, const dsa_param */*dp*/, | |
177 | const dsa_seed */*ds*/); | |
8b810a45 | 178 | |
c97fbcf9 MW |
179 | /* --- @dsa_h2n@ --- * |
180 | * | |
181 | * Arguments: @mp *d@ = destination integer | |
182 | * @mp *r@ = order of the DSA group | |
183 | * @const void *h@ = pointer to message hash | |
184 | * @size_t hsz@ = size (in bytes) of the hash output | |
185 | * | |
186 | * Returns: Resulting integer. | |
187 | * | |
188 | * Use: Converts a hash to an integer in the demented way necessary | |
189 | * for DSA/ECDSA. This is, of course, completely insane, but | |
190 | * there you go. | |
191 | */ | |
192 | ||
193 | extern mp *dsa_h2n(mp */*d*/, mp */*r*/, const void */*h*/, size_t /*hsz*/); | |
194 | ||
8b810a45 | 195 | /* --- @dsa_mksig@ --- * |
196 | * | |
197 | * Arguments: @const dsa_param *dp@ = pointer to DSA parameters | |
b3f05084 | 198 | * @mp *a@ = secret signing key |
199 | * @mp *m@ = message to be signed | |
200 | * @mp *k@ = random data | |
8b810a45 | 201 | * @mp **rr, **ss@ = where to put output parameters |
202 | * | |
203 | * Returns: --- | |
204 | * | |
205 | * Use: Computes a DSA signature of a message. | |
206 | */ | |
207 | ||
b3f05084 | 208 | extern void dsa_mksig(const dsa_param */*dp*/, mp */*a*/, |
209 | mp */*m*/, mp */*k*/, | |
8b810a45 | 210 | mp **/*rr*/, mp **/*ss*/); |
211 | ||
212 | /* --- @dsa_sign@ --- * | |
213 | * | |
214 | * Arguments: @dsa_param *dp@ = pointer to DSA parameters | |
215 | * @mp *a@ = pointer to secret signing key | |
216 | * @const void *m@ = pointer to message | |
217 | * @size_t msz@ = size of the message | |
218 | * @const void *k@ = secret random data for securing signature | |
219 | * @size_t ksz@ = size of secret data | |
220 | * @void *r@ = pointer to output space for @r@ | |
221 | * @size_t rsz@ = size of output space for @r@ | |
222 | * @void *s@ = pointer to output space for @s@ | |
223 | * @size_t ssz@ = size of output space for @s@ | |
224 | * | |
225 | * Returns: --- | |
226 | * | |
227 | * Use: Signs a message, storing the results in a big-endian binary | |
228 | * form. | |
229 | */ | |
230 | ||
231 | extern void dsa_sign(dsa_param */*dp*/, mp */*a*/, | |
232 | const void */*m*/, size_t /*msz*/, | |
233 | const void */*k*/, size_t /*ksz*/, | |
234 | void */*r*/, size_t /*rsz*/, | |
235 | void */*s*/, size_t /*ssz*/); | |
236 | ||
237 | /* --- @dsa_vrfy@ --- * | |
238 | * | |
239 | * Arguments: @const dsa_param *dp@ = pointer to DSA parameters | |
b3f05084 | 240 | * @mp *y@ = public verification key |
241 | * @mp *m@ = message which was signed | |
242 | * @mp *r, *s@ = the signature | |
8b810a45 | 243 | * |
244 | * Returns: Zero if the signature is a forgery, nonzero if it's valid. | |
245 | * | |
246 | * Use: Verifies a DSA digital signature. | |
247 | */ | |
248 | ||
b3f05084 | 249 | extern int dsa_vrfy(const dsa_param */*dp*/, mp */*y*/, |
250 | mp */*m*/, mp */*r*/, mp */*s*/); | |
8b810a45 | 251 | |
252 | /* --- @dsa_verify@ --- * | |
253 | * | |
254 | * Arguments: @const dsa_param *dp@ = pointer to DSA parameters | |
b3f05084 | 255 | * @mp *y@ = public verification key |
8b810a45 | 256 | * @const void *m@ = pointer to message block |
257 | * @size_t msz@ = size of message block | |
258 | * @const void *r@ = pointer to @r@ signature half | |
259 | * @size_t rsz@ = size of @r@ | |
260 | * @const void *s@ = pointer to @s@ signature half | |
261 | * @size_t ssz@ = size of @s@ | |
262 | * | |
263 | * Returns: Zero if the signature is a forgery, nonzero if it's valid. | |
264 | * | |
265 | * Use: Verifies a DSA digital signature. | |
266 | */ | |
267 | ||
b3f05084 | 268 | extern int dsa_verify(const dsa_param */*dp*/, mp */*y*/, |
b92da8eb | 269 | const void */*m*/, size_t /*msz*/, |
270 | const void */*r*/, size_t /*rsz*/, | |
271 | const void */*s*/, size_t /*ssz*/); | |
8b810a45 | 272 | |
273 | /*----- That's all, folks -------------------------------------------------*/ | |
274 | ||
275 | #ifdef __cplusplus | |
276 | } | |
277 | #endif | |
278 | ||
279 | #endif |