annotate tim_exptmod.c @ 15:6362d3854bb4 libtomcrypt-orig

0.96 release of LibTomCrypt
author Matt Johnston <matt@ucc.asn.au>
date Tue, 15 Jun 2004 14:07:21 +0000
parents
children 5d99163f7e32
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
15
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
2 *
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
3 * LibTomCrypt is a library that provides various cryptographic
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
4 * algorithms in a highly modular and flexible manner.
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
5 *
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
6 * The library is free for all purposes without any express
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
7 * guarantee it works.
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
8 *
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
9 * Tom St Denis, [email protected], http://libtomcrypt.org
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
10 */
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
11
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
12 /* RSA Code by Tom St Denis */
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
13 #include "mycrypt.h"
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
14
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
15 #ifdef RSA_TIMING
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
16
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
17 /* decrypts c into m */
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
18 int tim_exptmod(prng_state *prng, int prng_idx,
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
19 mp_int *c, mp_int *e, mp_int *d, mp_int *n, mp_int *m)
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
20 {
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
21 int err;
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
22 mp_int r, tmp, tmp2;
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
23 unsigned char *rtmp;
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
24 unsigned long rlen;
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
25
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
26 _ARGCHK(c != NULL);
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
27 _ARGCHK(e != NULL);
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
28 _ARGCHK(d != NULL);
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
29 _ARGCHK(n != NULL);
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
30 _ARGCHK(m != NULL);
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
31
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
32 if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) {
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
33 return err;
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
34 }
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
35
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
36 /* pick random r */
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
37 rtmp = XMALLOC(MAX_RSA_SIZE/8);
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
38 if (rtmp == NULL) {
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
39 return CRYPT_MEM;
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
40 }
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
41
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
42
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
43 rlen = mp_unsigned_bin_size(n);
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
44 if (prng_descriptor[prng_idx].read(rtmp, rlen, prng) != rlen) {
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
45 XFREE(rtmp);
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
46 return CRYPT_ERROR_READPRNG;
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
47 }
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
48
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
49 if ((err = mp_init_multi(&r, &tmp, &tmp2, NULL)) != MP_OKAY) {
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
50 XFREE(rtmp);
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
51 return mpi_to_ltc_error(err);
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
52 }
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
53
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
54 /* read in r */
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
55 if ((err = mp_read_unsigned_bin(&r, rtmp, rlen)) != MP_OKAY) { goto __ERR; }
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
56
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
57 /* compute tmp = r^e */
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
58 if ((err = mp_exptmod(&r, e, n, &tmp)) != MP_OKAY) { goto __ERR; }
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
59
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
60 /* multiply C into the mix */
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
61 if ((err = mp_mulmod(c, &tmp, n, &tmp)) != MP_OKAY) { goto __ERR; }
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
62
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
63 /* raise to d */
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
64 if ((err = mp_exptmod(&tmp, d, n, &tmp)) != MP_OKAY) { goto __ERR; }
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
65
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
66 /* invert r and multiply */
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
67 if ((err = mp_invmod(&r, n, &tmp2)) != MP_OKAY) { goto __ERR; }
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
68
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
69 /* multiply and we are totally set */
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
70 if ((err = mp_mulmod(&tmp, &tmp2, n, m)) != MP_OKAY) { goto __ERR; }
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
71
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
72 __ERR: mp_clear_multi(&r, &tmp, &tmp2, NULL);
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
73 XFREE(rtmp);
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
74 return mpi_to_ltc_error(err);
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
75 }
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
76
6362d3854bb4 0.96 release of LibTomCrypt
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
77 #endif