Mercurial > dropbear

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

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
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_hash.c 14 @file dsa_verify_hash.c
26 @param hashlen The length of the hash that was signed 26 @param hashlen The length of the hash that was signed
27 @param stat [out] The result of the signature verification, 1==valid, 0==invalid 27 @param stat [out] The result of the signature verification, 1==valid, 0==invalid
28 @param key The corresponding public DH key 28 @param key The corresponding public DH key
29 @return CRYPT_OK if successful (even if the signature is invalid) 29 @return CRYPT_OK if successful (even if the signature is invalid)
30 */ 30 */
31 int dsa_verify_hash_raw( mp_int *r, mp_int *s, 31 int dsa_verify_hash_raw( void *r, void *s,
32 const unsigned char *hash, unsigned long hashlen, 32 const unsigned char *hash, unsigned long hashlen,
33 int *stat, dsa_key *key) 33 int *stat, dsa_key *key)
34 { 34 {
35 mp_int w, v, u1, u2; 35 void *w, *v, *u1, *u2;
36 int err; 36 int err;
37 37
38 LTC_ARGCHK(r != NULL); 38 LTC_ARGCHK(r != NULL);
39 LTC_ARGCHK(s != NULL); 39 LTC_ARGCHK(s != NULL);
40 LTC_ARGCHK(stat != NULL); 40 LTC_ARGCHK(stat != NULL);
42 42
43 /* default to invalid signature */ 43 /* default to invalid signature */
44 *stat = 0; 44 *stat = 0;
45 45
46 /* init our variables */ 46 /* init our variables */
47 if ((err = mp_init_multi(&w, &v, &u1, &u2, NULL)) != MP_OKAY) { 47 if ((err = mp_init_multi(&w, &v, &u1, &u2, NULL)) != CRYPT_OK) {
48 return mpi_to_ltc_error(err); 48 return err;
49 } 49 }
50 50
51 /* neither r or s can be null or >q*/ 51 /* neither r or s can be null or >q*/
52 if (mp_iszero(r) == MP_YES || mp_iszero(s) == MP_YES || mp_cmp(r, &key->q) != MP_LT || mp_cmp(s, &key->q) != MP_LT) { 52 if (mp_iszero(r) == LTC_MP_YES || mp_iszero(s) == LTC_MP_YES || mp_cmp(r, key->q) != LTC_MP_LT || mp_cmp(s, key->q) != LTC_MP_LT) {
53 err = CRYPT_INVALID_PACKET; 53 err = CRYPT_INVALID_PACKET;
54 goto done; 54 goto error;
55 } 55 }
56 56
57 /* w = 1/s mod q */ 57 /* w = 1/s mod q */
58 if ((err = mp_invmod(s, &key->q, &w)) != MP_OKAY) { goto error; } 58 if ((err = mp_invmod(s, key->q, w)) != CRYPT_OK) { goto error; }
59 59
60 /* u1 = m * w mod q */ 60 /* u1 = m * w mod q */
61 if ((err = mp_read_unsigned_bin(&u1, (unsigned char *)hash, hashlen)) != MP_OKAY) { goto error; } 61 if ((err = mp_read_unsigned_bin(u1, (unsigned char *)hash, hashlen)) != CRYPT_OK) { goto error; }
62 if ((err = mp_mulmod(&u1, &w, &key->q, &u1)) != MP_OKAY) { goto error; } 62 if ((err = mp_mulmod(u1, w, key->q, u1)) != CRYPT_OK) { goto error; }
63 63
64 /* u2 = r*w mod q */ 64 /* u2 = r*w mod q */
65 if ((err = mp_mulmod(r, &w, &key->q, &u2)) != MP_OKAY) { goto error; } 65 if ((err = mp_mulmod(r, w, key->q, u2)) != CRYPT_OK) { goto error; }
66 66
67 /* v = g^u1 * y^u2 mod p mod q */ 67 /* v = g^u1 * y^u2 mod p mod q */
68 if ((err = mp_exptmod(&key->g, &u1, &key->p, &u1)) != MP_OKAY) { goto error; } 68 if ((err = mp_exptmod(key->g, u1, key->p, u1)) != CRYPT_OK) { goto error; }
69 if ((err = mp_exptmod(&key->y, &u2, &key->p, &u2)) != MP_OKAY) { goto error; } 69 if ((err = mp_exptmod(key->y, u2, key->p, u2)) != CRYPT_OK) { goto error; }
70 if ((err = mp_mulmod(&u1, &u2, &key->p, &v)) != MP_OKAY) { goto error; } 70 if ((err = mp_mulmod(u1, u2, key->p, v)) != CRYPT_OK) { goto error; }
71 if ((err = mp_mod(&v, &key->q, &v)) != MP_OKAY) { goto error; } 71 if ((err = mp_mod(v, key->q, v)) != CRYPT_OK) { goto error; }
72 72
73 /* if r = v then we're set */ 73 /* if r = v then we're set */
74 if (mp_cmp(r, &v) == MP_EQ) { 74 if (mp_cmp(r, v) == LTC_MP_EQ) {
75 *stat = 1; 75 *stat = 1;
76 } 76 }
77 77
78 err = CRYPT_OK; 78 err = CRYPT_OK;
79 goto done; 79 error:
80 80 mp_clear_multi(w, v, u1, u2, NULL);
81 error : err = mpi_to_ltc_error(err);
82 done : mp_clear_multi(&w, &v, &u1, &u2, NULL);
83 return err; 81 return err;
84 } 82 }
85 83
86 /** 84 /**
87 Verify a DSA signature 85 Verify a DSA signature
96 int dsa_verify_hash(const unsigned char *sig, unsigned long siglen, 94 int dsa_verify_hash(const unsigned char *sig, unsigned long siglen,
97 const unsigned char *hash, unsigned long hashlen, 95 const unsigned char *hash, unsigned long hashlen,
98 int *stat, dsa_key *key) 96 int *stat, dsa_key *key)
99 { 97 {
100 int err; 98 int err;
101 mp_int r, s; 99 void *r, *s;
102 100
103 if ((err = mp_init_multi(&r, &s, NULL)) != CRYPT_OK) { 101 if ((err = mp_init_multi(&r, &s, NULL)) != CRYPT_OK) {
104 return CRYPT_MEM; 102 return CRYPT_MEM;
105 } 103 }
106 104
107 /* decode the sequence */ 105 /* decode the sequence */
108 if ((err = der_decode_sequence_multi(sig, siglen, 106 if ((err = der_decode_sequence_multi(sig, siglen,
109 LTC_ASN1_INTEGER, 1UL, &r, 107 LTC_ASN1_INTEGER, 1UL, r,
110 LTC_ASN1_INTEGER, 1UL, &s, 108 LTC_ASN1_INTEGER, 1UL, s,
111 LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) { 109 LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
112 goto LBL_ERR; 110 goto LBL_ERR;
113 } 111 }
114 112
115 /* do the op */ 113 /* do the op */
116 err = dsa_verify_hash_raw(&r, &s, hash, hashlen, stat, key); 114 err = dsa_verify_hash_raw(r, s, hash, hashlen, stat, key);
117 115
118 LBL_ERR: 116 LBL_ERR:
119 mp_clear_multi(&r, &s, NULL); 117 mp_clear_multi(r, s, NULL);
120 return err; 118 return err;
121 } 119 }
122 120
123 #endif 121 #endif
124 122
125 123
126 /* $Source: /cvs/libtom/libtomcrypt/src/pk/dsa/dsa_verify_hash.c,v $ */ 124 /* $Source: /cvs/libtom/libtomcrypt/src/pk/dsa/dsa_verify_hash.c,v $ */
127 /* $Revision: 1.8 $ */ 125 /* $Revision: 1.13 $ */
128 /* $Date: 2005/05/15 21:48:59 $ */ 126 /* $Date: 2006/12/04 03:18:43 $ */