3 * $Id: oaep.c,v 1.3 2001/02/22 09:04:39 mdw Exp $
5 * Optimal asymmetric encryption packing
7 * (c) 2000 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
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.
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.
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,
30 /*----- Revision history --------------------------------------------------*
33 * Revision 1.3 2001/02/22 09:04:39 mdw
36 * Revision 1.2 2000/07/15 10:01:48 mdw
37 * Test rig added, based on RIPEMD160-MGF1 test vectors.
39 * Revision 1.1 2000/07/01 11:18:30 mdw
40 * Support for Optimal Asymmetric Encryption Padding.
44 /*----- Header files ------------------------------------------------------*/
48 #include <mLib/alloc.h>
49 #include <mLib/bits.h>
50 #include <mLib/dstr.h>
57 /*----- Main code ---------------------------------------------------------*/
59 /* --- @oaep_encode@ --- *
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
67 * Returns: Zero if all went well, negative on failure.
69 * Use: Implements the operation @EME-OAEP-ENCODE@, as defined in
70 * PKCS#1 v. 2.0 (RFC2437).
73 int oaep_encode(const void *msg
, size_t msz
, void *buf
, size_t sz
, void *p
)
76 size_t hsz
= o
->ch
->hashsz
;
83 /* --- Ensure that everything is sensibly sized --- */
85 if (2 * hsz
+ 2 + msz
> sz
)
88 /* --- Make the `seed' value --- */
94 o
->r
->ops
->fill(o
->r
, q
, hsz
);
96 /* --- Fill in the rest of the buffer --- */
99 h
->ops
->hash(h
, o
->ep
, o
->epsz
);
103 n
= sz
- 2 * hsz
- msz
- 1;
107 memcpy(pp
, msg
, msz
);
109 /* --- Do the packing --- */
112 c
= o
->cc
->init(q
, hsz
);
113 c
->ops
->encrypt(c
, mq
, mq
, n
);
116 c
= o
->cc
->init(mq
, n
);
117 c
->ops
->encrypt(c
, q
, q
, hsz
);
125 /* --- @oaep_decode@ --- *
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
132 * Returns: The length of the output string if successful, negative on
135 * Use: Implements the operation @EME-OAEP-DECODE@, as defined in
136 * PKCS#1 v. 2.0 (RFC2437).
139 int oaep_decode(const void *buf
, size_t sz
, dstr
*d
, void *p
)
147 size_t hsz
= o
->ch
->hashsz
;
150 /* --- Ensure that the block is large enough --- */
155 q
= x_alloc(d
->a
, sz
);
158 /* --- Decrypt the message --- */
166 c
= o
->cc
->init(mq
, n
);
167 c
->ops
->decrypt(c
, q
, q
, hsz
);
170 c
= o
->cc
->init(q
, hsz
);
171 c
->ops
->decrypt(c
, mq
, mq
, n
);
175 /* --- Check the hash on the encoding parameters --- */
178 h
->ops
->hash(h
, o
->ep
, o
->epsz
);
181 if (memcmp(q
, mq
, hsz
) != 0)
184 /* --- Now find the start of the actual message --- */
187 while (*pp
== 0 && pp
< qq
)
189 if (pp
>= qq
|| *pp
++ != 1)
200 /*----- Test rig ----------------------------------------------------------*/
204 #include <mLib/testrig.h>
207 #include "rmd160-mgf.h"
209 typedef struct gctx
{
214 static void rfill(grand
*r
, void *buf
, size_t sz
)
217 memcpy(buf
, g
->buf
, sz
);
220 static const grand_ops gops
= {
226 static int verify(dstr
*v
)
233 dstr_ensure(&d
, v
[3].len
);
236 gr
.buf
= (octet
*)v
[2].buf
;
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) {
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
);
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) {
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
);
273 static test_chunk tests
[] = {
274 { "oaep", verify
, { &type_hex
, &type_hex
, &type_hex
, &type_hex
, 0 } },
278 int main(int argc
, char *argv
[])
280 test_run(argc
, argv
, tests
, SRCDIR
"/tests/oaep");
286 /*----- That's all, folks -------------------------------------------------*/