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Add an internal-representation no-op function.
[u/mdw/catacomb] / oaep.c
CommitLineData
99a01cb9 1/* -*-c-*-
2 *
827a6719 3 * $Id: oaep.c,v 1.3 2001/02/22 09:04:39 mdw Exp $
99a01cb9 4 *
5 * Optimal asymmetric encryption packing
6 *
7 * (c) 2000 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: oaep.c,v $
827a6719 33 * Revision 1.3 2001/02/22 09:04:39 mdw
34 * Fix memory leaks.
35 *
49db8dbe 36 * Revision 1.2 2000/07/15 10:01:48 mdw
37 * Test rig added, based on RIPEMD160-MGF1 test vectors.
38 *
99a01cb9 39 * Revision 1.1 2000/07/01 11:18:30 mdw
40 * Support for Optimal Asymmetric Encryption Padding.
41 *
42 */
43
44/*----- Header files ------------------------------------------------------*/
45
46#include <string.h>
47
48#include <mLib/alloc.h>
49#include <mLib/bits.h>
50#include <mLib/dstr.h>
51
52#include "gcipher.h"
53#include "ghash.h"
54#include "grand.h"
55#include "oaep.h"
56
57/*----- Main code ---------------------------------------------------------*/
58
59/* --- @oaep_encode@ --- *
60 *
61 * Arguments: @const void *msg@ = pointer to message data
62 * @size_t msz@ = size of message data
63 * @void *buf@ = pointer to output buffer
64 * @size_t sz@ = size of the output buffer
65 * @void *p@ = pointer to OAEP parameter block
66 *
67 * Returns: Zero if all went well, negative on failure.
68 *
69 * Use: Implements the operation @EME-OAEP-ENCODE@, as defined in
70 * PKCS#1 v. 2.0 (RFC2437).
71 */
72
73int oaep_encode(const void *msg, size_t msz, void *buf, size_t sz, void *p)
74{
75 oaep *o = p;
76 size_t hsz = o->ch->hashsz;
827a6719 77 ghash *h;
99a01cb9 78 octet *q, *mq, *qq;
79 octet *pp;
80 gcipher *c;
81 size_t n;
82
83 /* --- Ensure that everything is sensibly sized --- */
84
85 if (2 * hsz + 2 + msz > sz)
86 return (-1);
87
88 /* --- Make the `seed' value --- */
89
90 q = buf;
91 *q++ = 0; sz--;
92 mq = q + hsz;
93 qq = q + sz;
94 o->r->ops->fill(o->r, q, hsz);
95
96 /* --- Fill in the rest of the buffer --- */
97
827a6719 98 h = o->ch->init();
99a01cb9 99 h->ops->hash(h, o->ep, o->epsz);
100 h->ops->done(h, mq);
101 h->ops->destroy(h);
102 pp = mq + hsz;
103 n = sz - 2 * hsz - msz - 1;
104 memset(pp, 0, n);
105 pp += n;
106 *pp++ = 1;
107 memcpy(pp, msg, msz);
108
109 /* --- Do the packing --- */
110
111 n = sz - hsz;
112 c = o->cc->init(q, hsz);
113 c->ops->encrypt(c, mq, mq, n);
114 c->ops->destroy(c);
115
116 c = o->cc->init(mq, n);
117 c->ops->encrypt(c, q, q, hsz);
118 c->ops->destroy(c);
119
120 /* --- Done --- */
121
122 return (0);
123}
124
125/* --- @oaep_decode@ --- *
126 *
127 * Arguments: @const void *buf@ = pointer to encoded buffer
128 * @size_t sz@ = size of the encoded buffer
129 * @dstr *d@ = pointer to destination string
130 * @void *p@ = pointer to OAEP parameter block
131 *
132 * Returns: The length of the output string if successful, negative on
133 * failure.
134 *
135 * Use: Implements the operation @EME-OAEP-DECODE@, as defined in
136 * PKCS#1 v. 2.0 (RFC2437).
137 */
138
139int oaep_decode(const void *buf, size_t sz, dstr *d, void *p)
140{
141 oaep *o = p;
142 gcipher *c;
143 ghash *h;
144 octet *q, *mq, *qq;
145 octet *pp;
146 size_t n;
147 size_t hsz = o->ch->hashsz;
148 int rc = -1;
149
150 /* --- Ensure that the block is large enough --- */
151
152 if (sz < 2 * hsz)
153 return (-1);
154
155 q = x_alloc(d->a, sz);
156 memcpy(q, buf, sz);
157
158 /* --- Decrypt the message --- */
159
160 if (*q != 0)
161 goto fail;
162 q++; sz--;
163 mq = q + hsz;
164 qq = q + sz;
165 n = sz - hsz;
166 c = o->cc->init(mq, n);
167 c->ops->decrypt(c, q, q, hsz);
168 c->ops->destroy(c);
169
170 c = o->cc->init(q, hsz);
171 c->ops->decrypt(c, mq, mq, n);
172 c->ops->destroy(c);
173 q--;
174
175 /* --- Check the hash on the encoding parameters --- */
176
177 h = o->ch->init();
178 h->ops->hash(h, o->ep, o->epsz);
179 h->ops->done(h, q);
827a6719 180 h->ops->destroy(h);
99a01cb9 181 if (memcmp(q, mq, hsz) != 0)
182 goto fail;
183
184 /* --- Now find the start of the actual message --- */
185
186 pp = mq + hsz;
187 while (*pp == 0 && pp < qq)
188 pp++;
189 if (pp >= qq || *pp++ != 1)
190 return (-1);
191 n = qq - pp;
192 dstr_putm(d, pp, n);
193 rc = n;
194
195fail:
196 x_free(d->a, q);
197 return (rc);
198}
199
49db8dbe 200/*----- Test rig ----------------------------------------------------------*/
201
202#ifdef TEST_RIG
203
204#include <mLib/testrig.h>
205
206#include "rmd160.h"
207#include "rmd160-mgf.h"
208
209typedef struct gctx {
210 grand r;
211 octet *buf;
212} gctx;
213
214static void rfill(grand *r, void *buf, size_t sz)
215{
216 gctx *g = (gctx *)r;
217 memcpy(buf, g->buf, sz);
218}
219
220static const grand_ops gops = {
221 "const", 0, 0,
222 0, 0,
223 0, 0, 0, 0, rfill
224};
225
226static int verify(dstr *v)
227{
228 gctx gr;
229 dstr d = DSTR_INIT;
230 oaep o;
231 int ok = 1;
232
233 dstr_ensure(&d, v[3].len);
234 d.len = v[3].len;
235 gr.r.ops = &gops;
827a6719 236 gr.buf = (octet *)v[2].buf;
49db8dbe 237
238 o.cc = &rmd160_mgf;
239 o.ch = &rmd160;
240 o.r = &gr.r;
241 o.ep = v[1].buf;
242 o.epsz = v[1].len;
243
244 if (oaep_encode(v[0].buf, v[0].len, d.buf, d.len, &o) ||
245 memcmp(d.buf, v[3].buf, d.len) != 0) {
246 ok = 0;
247 fputs("\nfailure in oaep_encode", stderr);
248 fputs("\n message = ", stderr); type_hex.dump(&v[0], stderr);
249 fputs("\n params = ", stderr); type_hex.dump(&v[1], stderr);
250 fputs("\n salt = ", stderr); type_hex.dump(&v[2], stderr);
251 fputs("\nexpected = ", stderr); type_hex.dump(&v[3], stderr);
252 fputs("\n output = ", stderr); type_hex.dump(&d, stderr);
253 fputc('\n', stderr);
254 }
255
256 DRESET(&d);
257 if (oaep_decode(v[3].buf, v[3].len, &d, &o) < 0 ||
258 d.len != v[0].len || memcmp(d.buf, v[0].buf, d.len) != 0) {
259 ok = 0;
260 fputs("\nfailure in oaep_decode", stderr);
261 fputs("\n goop = ", stderr); type_hex.dump(&v[3], stderr);
262 fputs("\n params = ", stderr); type_hex.dump(&v[1], stderr);
263 fputs("\n salt = ", stderr); type_hex.dump(&v[2], stderr);
264 fputs("\nexpected = ", stderr); type_hex.dump(&v[0], stderr);
265 fputs("\n output = ", stderr); type_hex.dump(&d, stderr);
266 fputc('\n', stderr);
267 }
268
269 dstr_destroy(&d);
270 return (ok);
271}
272
273static test_chunk tests[] = {
274 { "oaep", verify, { &type_hex, &type_hex, &type_hex, &type_hex, 0 } },
275 { 0, 0, { 0 } }
276};
277
278int main(int argc, char *argv[])
279{
280 test_run(argc, argv, tests, SRCDIR "/tests/oaep");
281 return (0);
282}
283
284#endif
285
99a01cb9 286/*----- That's all, folks -------------------------------------------------*/
Catacomb cryptographic library (downstream of http://git.distorted.org.uk/~mdw/catacomb/)