diff options
Diffstat (limited to 'openssl/crypto/ecdsa/ecs_ossl.c')
| -rw-r--r-- | openssl/crypto/ecdsa/ecs_ossl.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/openssl/crypto/ecdsa/ecs_ossl.c b/openssl/crypto/ecdsa/ecs_ossl.c index 551cf5068..1bbf328de 100644 --- a/openssl/crypto/ecdsa/ecs_ossl.c +++ b/openssl/crypto/ecdsa/ecs_ossl.c @@ -144,6 +144,14 @@ static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp, } while (BN_is_zero(k)); + /* We do not want timing information to leak the length of k, + * so we compute G*k using an equivalent scalar of fixed + * bit-length. */ + + if (!BN_add(k, k, order)) goto err; + if (BN_num_bits(k) <= BN_num_bits(order)) + if (!BN_add(k, k, order)) goto err; + /* compute r the x-coordinate of generator * k */ if (!EC_POINT_mul(group, tmp_point, k, NULL, NULL, ctx)) { |