- refactored random mp_int generation and byte->mp_int code

- added RSA blinding

--HG--
extra : convert_revision : 5d5b4657a24a1c8f53c6fc45d5ec29ddb85fb45a

1 files changed, 8 insertions, 22 deletions

diff --git a/dss.c b/dss.c
index 5cf018d..cb877ca 100644
--- a/dss.c
+++ b/dss.c
@@ -190,10 +190,8 @@ int buf_dss_verify(buffer* buf, dss_key *key, const unsigned char* data,
 	/* create the signature - s' and r' are the received signatures in buf */
 	/* w = (s')-1 mod q */
 	/* let val1 = s' */
-	if (mp_read_unsigned_bin(&val1, &string[SHA1_HASH_SIZE], SHA1_HASH_SIZE)
-			!= MP_OKAY) {
-		goto out;
-	}
+	bytes_to_mp(&val1, &string[SHA1_HASH_SIZE], SHA1_HASH_SIZE);
+
 	if (mp_cmp(&val1, key->q) != MP_LT) {
 		TRACE(("verify failed, s' >= q"))
 		goto out;
@@ -205,9 +203,8 @@ int buf_dss_verify(buffer* buf, dss_key *key, const unsigned char* data,
 
 	/* u1 = ((SHA(M')w) mod q */
 	/* let val1 = SHA(M') = msghash */
-	if (mp_read_unsigned_bin(&val1, msghash, SHA1_HASH_SIZE) != MP_OKAY) {
-		goto out;
-	}
+	bytes_to_mp(&val1, msghash, SHA1_HASH_SIZE);
+
 	/* let val3 = u1 = ((SHA(M')w) mod q */
 	if (mp_mulmod(&val1, &val2, key->q, &val3) != MP_OKAY) {
 		goto out;
@@ -215,10 +212,7 @@ int buf_dss_verify(buffer* buf, dss_key *key, const unsigned char* data,
 
 	/* u2 = ((r')w) mod q */
 	/* let val1 = r' */
-	if (mp_read_unsigned_bin(&val1, &string[0], SHA1_HASH_SIZE)
-			!= MP_OKAY) {
-		goto out;
-	}
+	bytes_to_mp(&val1, &string[0], SHA1_HASH_SIZE);
 	if (mp_cmp(&val1, key->q) != MP_LT) {
 		TRACE(("verify failed, r' >= q"))
 		goto out;
@@ -306,8 +300,6 @@ void buf_put_dss_sign(buffer* buf, dss_key *key, const unsigned char* data,
 	unsigned char *privkeytmp;
 	unsigned char proto_k[SHA512_HASH_SIZE];
 	DEF_MP_INT(dss_protok);
-#else
-	unsigned char kbuf[SHA1_HASH_SIZE];
 #endif
 	DEF_MP_INT(dss_k);
 	DEF_MP_INT(dss_m);
@@ -345,22 +337,16 @@ void buf_put_dss_sign(buffer* buf, dss_key *key, const unsigned char* data,
 
 	/* generate k */
 	m_mp_init(&dss_protok);
-	bytestomp(&dss_protok, proto_k, SHA512_HASH_SIZE);
+	bytes_to_mp(&dss_protok, proto_k, SHA512_HASH_SIZE);
 	mp_mod(&dss_protok, key->q, &dss_k);
 	mp_clear(&dss_protok);
 	m_burn(proto_k, SHA512_HASH_SIZE);
 #else /* DSS_PROTOK not defined*/
-	do {
-		genrandom(kbuf, SHA1_HASH_SIZE);
-		if (mp_read_unsigned_bin(&dss_k, kbuf, SHA1_HASH_SIZE) != MP_OKAY) {
-			dropbear_exit("dss error");
-		}
-	} while (mp_cmp(&dss_k, key->q) == MP_GT || mp_cmp_d(&dss_k, 0) != MP_GT);
-	m_burn(kbuf, SHA1_HASH_SIZE);
+	gen_random_mpint(key->q, &dss_k);
 #endif
 
 	/* now generate the actual signature */
-	bytestomp(&dss_m, msghash, SHA1_HASH_SIZE);
+	bytes_to_mp(&dss_m, msghash, SHA1_HASH_SIZE);
 
 	/* g^k mod p */
 	if (mp_exptmod(key->g, &dss_k, key->p, &dss_temp1) !=  MP_OKAY) {