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add support for DSA with SHA2

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This commit is contained in:
Nils Larsch
2007-02-03 14:41:12 +00:00
parent 0501f02b06
commit 357d5de5b9
16 changed files with 270 additions and 75 deletions
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43
crypto/dsa/dsa_ossl.c
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@@ -61,6 +61,7 @@
#include <stdio.h>
#include "cryptlib.h"
#include <openssl/bn.h>
#include <openssl/sha.h>
#include <openssl/dsa.h>
#include <openssl/rand.h>
#include <openssl/asn1.h>
@@ -133,7 +134,7 @@ static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)
BIGNUM m;
BIGNUM xr;
BN_CTX *ctx=NULL;
int i,reason=ERR_R_BN_LIB;
int i, j, reason=ERR_R_BN_LIB;
DSA_SIG *ret=NULL;
BN_init(&m);
@@ -148,8 +149,9 @@ static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)
s=BN_new();
if (s == NULL) goto err;
i=BN_num_bytes(dsa->q); /* should be 20 */
if ((dlen > i) || (dlen > 50))
/* reject a excessive digest length (currently at most
* dsa-with-SHA256 is supported) */
if (dlen > SHA256_DIGEST_LENGTH)
{
reason=DSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE;
goto err;
@@ -170,7 +172,17 @@ static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)
dsa->r=NULL;
}
if (BN_bin2bn(dgst,dlen,&m) == NULL) goto err;
if (BN_bin2bn(dgst,dlen,&m) == NULL)
goto err;
i = BN_num_bytes(dsa->q);
if (dlen > i)
{
/* if the digest length is greater than the size of q use the
* BN_num_bits(dsa->q) leftmost bits of the digest, see
* fips 186-3, 4.2 */
if (!BN_rshift(&m, &m, (dlen - i) << 3))
goto err;
}
/* Compute s = inv(k) (m + xr) mod q */
if (!BN_mod_mul(&xr,dsa->priv_key,r,dsa->q,ctx)) goto err;/* s = xr */
@@ -296,14 +308,16 @@ static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig,
BN_CTX *ctx;
BIGNUM u1,u2,t1;
BN_MONT_CTX *mont=NULL;
int ret = -1;
int ret = -1, i, j;
if (!dsa->p || !dsa->q || !dsa->g)
{
DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MISSING_PARAMETERS);
return -1;
}
if (BN_num_bits(dsa->q) != 160)
i = BN_num_bits(dsa->q);
/* fips 186-3 allows only different sizes for q */
if (i != 160 && i != 224 && i != 256)
{
DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_BAD_Q_VALUE);
return -1;
@@ -315,6 +329,14 @@ static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig,
return -1;
}
/* reject a excessive digest length (currently at most
* dsa-with-SHA256 is supported) */
if (dgst_len > SHA256_DIGEST_LENGTH)
{
DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
return -1;
}
BN_init(&u1);
BN_init(&u2);
BN_init(&t1);
@@ -340,6 +362,15 @@ static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig,
/* save M in u1 */
if (BN_bin2bn(dgst,dgst_len,&u1) == NULL) goto err;
j = dgst_len << 3;
if (j > i)
{
/* if the digest length is greater than the size of q use the
* BN_num_bits(dsa->q) leftmost bits of the digest, see
* fips 186-3, 4.2 */
if (!BN_rshift(&u1, &u1, j - i))
goto err;
}
/* u1 = M * w mod q */
if (!BN_mod_mul(&u1,&u1,&u2,dsa->q,ctx)) goto err;