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comparison libtomcrypt/src/pk/dsa/dsa_verify_key.c @ 382:0cbe8f6dbf9e

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propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 2af22fb4e878750b88f80f90d439b316d229796f) to branch 'au.asn.ucc.matt.dropbear' (head 02c413252c90e9de8e03d91e9939dde3029f5c0a)
author Matt Johnston <matt@ucc.asn.au>
date Thu, 11 Jan 2007 02:41:05 +0000
parents 1b9e69c058d2
children f849a5ca2efc
comparison
equal deleted inserted replaced
379:b66a00272a90 382:0cbe8f6dbf9e
4 * algorithms in a highly modular and flexible manner. 4 * algorithms in a highly modular and flexible manner.
5 * 5 *
6 * The library is free for all purposes without any express 6 * The library is free for all purposes without any express
7 * guarantee it works. 7 * guarantee it works.
8 * 8 *
9 * Tom St Denis, [email protected], http://libtomcrypt.org 9 * Tom St Denis, [email protected], http://libtomcrypt.com
10 */ 10 */
11 #include "tomcrypt.h" 11 #include "tomcrypt.h"
12 12
13 /** 13 /**
14 @file dsa_verify_key.c 14 @file dsa_verify_key.c
23 @param stat [out] Result of test, 1==valid, 0==invalid 23 @param stat [out] Result of test, 1==valid, 0==invalid
24 @return CRYPT_OK if successful 24 @return CRYPT_OK if successful
25 */ 25 */
26 int dsa_verify_key(dsa_key *key, int *stat) 26 int dsa_verify_key(dsa_key *key, int *stat)
27 { 27 {
28 mp_int tmp, tmp2; 28 void *tmp, *tmp2;
29 int res, err; 29 int res, err;
30 30
31 LTC_ARGCHK(key != NULL); 31 LTC_ARGCHK(key != NULL);
32 LTC_ARGCHK(stat != NULL); 32 LTC_ARGCHK(stat != NULL);
33 33
34 /* default to an invalid key */ 34 /* default to an invalid key */
35 *stat = 0; 35 *stat = 0;
36 36
37 /* first make sure key->q and key->p are prime */ 37 /* first make sure key->q and key->p are prime */
38 if ((err = is_prime(&key->q, &res)) != CRYPT_OK) { 38 if ((err = mp_prime_is_prime(key->q, 8, &res)) != CRYPT_OK) {
39 return err; 39 return err;
40 } 40 }
41 if (res == 0) { 41 if (res == 0) {
42 return CRYPT_OK; 42 return CRYPT_OK;
43 } 43 }
44 44
45 45 if ((err = mp_prime_is_prime(key->p, 8, &res)) != CRYPT_OK) {
46 if ((err = is_prime(&key->p, &res)) != CRYPT_OK) {
47 return err; 46 return err;
48 } 47 }
49 if (res == 0) { 48 if (res == 0) {
50 return CRYPT_OK; 49 return CRYPT_OK;
51 } 50 }
52 51
53 /* now make sure that g is not -1, 0 or 1 and <p */ 52 /* now make sure that g is not -1, 0 or 1 and <p */
54 if (mp_cmp_d(&key->g, 0) == MP_EQ || mp_cmp_d(&key->g, 1) == MP_EQ) { 53 if (mp_cmp_d(key->g, 0) == LTC_MP_EQ || mp_cmp_d(key->g, 1) == LTC_MP_EQ) {
55 return CRYPT_OK; 54 return CRYPT_OK;
56 } 55 }
57 if ((err = mp_init_multi(&tmp, &tmp2, NULL)) != MP_OKAY) { goto error; } 56 if ((err = mp_init_multi(&tmp, &tmp2, NULL)) != CRYPT_OK) { return err; }
58 if ((err = mp_sub_d(&key->p, 1, &tmp)) != MP_OKAY) { goto error; } 57 if ((err = mp_sub_d(key->p, 1, tmp)) != CRYPT_OK) { goto error; }
59 if (mp_cmp(&tmp, &key->g) == MP_EQ || mp_cmp(&key->g, &key->p) != MP_LT) { 58 if (mp_cmp(tmp, key->g) == LTC_MP_EQ || mp_cmp(key->g, key->p) != LTC_MP_LT) {
60 err = CRYPT_OK; 59 err = CRYPT_OK;
61 goto done; 60 goto error;
62 } 61 }
63 62
64 /* 1 < y < p-1 */ 63 /* 1 < y < p-1 */
65 if (!(mp_cmp_d(&key->y, 1) == MP_GT && mp_cmp(&key->y, &tmp) == MP_LT)) { 64 if (!(mp_cmp_d(key->y, 1) == LTC_MP_GT && mp_cmp(key->y, tmp) == LTC_MP_LT)) {
66 err = CRYPT_OK; 65 err = CRYPT_OK;
67 goto done; 66 goto error;
68 } 67 }
69 68
70 /* now we have to make sure that g^q = 1, and that p-1/q gives 0 remainder */ 69 /* now we have to make sure that g^q = 1, and that p-1/q gives 0 remainder */
71 if ((err = mp_div(&tmp, &key->q, &tmp, &tmp2)) != MP_OKAY) { goto error; } 70 if ((err = mp_div(tmp, key->q, tmp, tmp2)) != CRYPT_OK) { goto error; }
72 if (mp_iszero(&tmp2) != MP_YES) { 71 if (mp_iszero(tmp2) != LTC_MP_YES) {
73 err = CRYPT_OK; 72 err = CRYPT_OK;
74 goto done; 73 goto error;
75 } 74 }
76 75
77 if ((err = mp_exptmod(&key->g, &key->q, &key->p, &tmp)) != MP_OKAY) { goto error; } 76 if ((err = mp_exptmod(key->g, key->q, key->p, tmp)) != CRYPT_OK) { goto error; }
78 if (mp_cmp_d(&tmp, 1) != MP_EQ) { 77 if (mp_cmp_d(tmp, 1) != LTC_MP_EQ) {
79 err = CRYPT_OK; 78 err = CRYPT_OK;
80 goto done; 79 goto error;
81 } 80 }
82 81
83 /* now we have to make sure that y^q = 1, this makes sure y \in g^x mod p */ 82 /* now we have to make sure that y^q = 1, this makes sure y \in g^x mod p */
84 if ((err = mp_exptmod(&key->y, &key->q, &key->p, &tmp)) != MP_OKAY) { goto error; } 83 if ((err = mp_exptmod(key->y, key->q, key->p, tmp)) != CRYPT_OK) { goto error; }
85 if (mp_cmp_d(&tmp, 1) != MP_EQ) { 84 if (mp_cmp_d(tmp, 1) != LTC_MP_EQ) {
86 err = CRYPT_OK; 85 err = CRYPT_OK;
87 goto done; 86 goto error;
88 } 87 }
89 88
90 /* at this point we are out of tests ;-( */ 89 /* at this point we are out of tests ;-( */
91 err = CRYPT_OK; 90 err = CRYPT_OK;
92 *stat = 1; 91 *stat = 1;
93 goto done; 92 error:
94 error: err = mpi_to_ltc_error(err); 93 mp_clear_multi(tmp, tmp2, NULL);
95 done : mp_clear_multi(&tmp, &tmp2, NULL);
96 return err; 94 return err;
97 } 95 }
98 #endif 96 #endif
99 97
100 /* $Source: /cvs/libtom/libtomcrypt/src/pk/dsa/dsa_verify_key.c,v $ */ 98 /* $Source: /cvs/libtom/libtomcrypt/src/pk/dsa/dsa_verify_key.c,v $ */
101 /* $Revision: 1.3 $ */ 99 /* $Revision: 1.6 $ */
102 /* $Date: 2005/05/05 14:35:59 $ */ 100 /* $Date: 2006/12/04 03:18:43 $ */