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Add secure DSA nonce flag.

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This change adds the option to calculate (EC)DSA nonces by hashing the
message and private key along with entropy to avoid leaking the private
key if the PRNG fails.
This commit is contained in:
Adam Langley
2013-01-24 16:27:28 -05:00
committed by Ben Laurie
parent 64a786a292
commit 8a99cb29d1
15 changed files with 201 additions and 30 deletions
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37
crypto/ecdsa/ecs_ossl.c
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@@ -62,11 +62,13 @@
#include <openssl/err.h>
#include <openssl/obj_mac.h>
#include <openssl/bn.h>
#include <openssl/rand.h>
static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dlen,
const BIGNUM *, const BIGNUM *, EC_KEY *eckey);
static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
BIGNUM **rp);
static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in,
BIGNUM **kinvp, BIGNUM **rp,
const unsigned char *dgst, int dlen);
static int ecdsa_do_verify(const unsigned char *dgst, int dgst_len,
const ECDSA_SIG *sig, EC_KEY *eckey);
@@ -88,8 +90,9 @@ const ECDSA_METHOD *ECDSA_OpenSSL(void)
return &openssl_ecdsa_meth;
}
static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
BIGNUM **rp)
static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in,
BIGNUM **kinvp, BIGNUM **rp,
const unsigned char *dgst, int dlen)
{
BN_CTX *ctx = NULL;
BIGNUM *k = NULL, *r = NULL, *order = NULL, *X = NULL;
@@ -143,11 +146,26 @@ static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
{
/* get random k */
do
if (!BN_rand_range(k, order))
#ifndef OPENSSL_NO_SHA512
if (EC_KEY_get_nonce_from_hash(eckey))
{
ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,
ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
goto err;
if (!BN_generate_dsa_nonce(k, order, EC_KEY_get0_private_key(eckey),
dgst, dlen, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,
ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
goto err;
}
}
else
#endif
{
if (!BN_rand_range(k, order))
{
ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,
ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
goto err;
}
}
while (BN_is_zero(k));
@@ -302,8 +320,7 @@ static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len,
{
if (in_kinv == NULL || in_r == NULL)
{
if (!ecdsa->meth->ecdsa_sign_setup(eckey, ctx,
&kinv, &ret->r))
if (!ecdsa->meth->ecdsa_sign_setup(eckey, ctx, &kinv, &ret->r, dgst, dgst_len))
{
ECDSAerr(ECDSA_F_ECDSA_DO_SIGN,ERR_R_ECDSA_LIB);
goto err;