diff options
author | Bodo Möller <bodo@openssl.org> | 2005-05-16 01:43:31 +0000 |
---|---|---|
committer | Bodo Möller <bodo@openssl.org> | 2005-05-16 01:43:31 +0000 |
commit | 46a643763de6d8e39ecf6f76fa79b4d04885aa59 (patch) | |
tree | e1f3cfc98bddba797b5300977dbf3223f008fc4a /crypto/bn/exptest.c | |
parent | 92c44685724c0d993ea8920577680f3c0a1d79c8 (diff) |
Implement fixed-window exponentiation to mitigate hyper-threading
timing attacks.
BN_FLG_EXP_CONSTTIME requests this algorithm, and this done by default for
RSA/DSA/DH private key computations unless
RSA_FLAG_NO_EXP_CONSTTIME/DSA_FLAG_NO_EXP_CONSTTIME/
DH_FLAG_NO_EXP_CONSTTIME is set.
Submitted by: Matthew D Wood
Reviewed by: Bodo Moeller
Diffstat (limited to 'crypto/bn/exptest.c')
-rw-r--r-- | crypto/bn/exptest.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/crypto/bn/exptest.c b/crypto/bn/exptest.c index 37aec55b89..f598a07cf5 100644 --- a/crypto/bn/exptest.c +++ b/crypto/bn/exptest.c @@ -77,7 +77,7 @@ int main(int argc, char *argv[]) BIO *out=NULL; int i,ret; unsigned char c; - BIGNUM *r_mont,*r_recp,*r_simple,*a,*b,*m; + BIGNUM *r_mont,*r_mont_const,*r_recp,*r_simple,*a,*b,*m; RAND_seed(rnd_seed, sizeof rnd_seed); /* or BN_rand may fail, and we don't * even check its return value @@ -88,6 +88,7 @@ int main(int argc, char *argv[]) ctx=BN_CTX_new(); if (ctx == NULL) EXIT(1); r_mont=BN_new(); + r_mont_const=BN_new(); r_recp=BN_new(); r_simple=BN_new(); a=BN_new(); @@ -143,8 +144,17 @@ int main(int argc, char *argv[]) EXIT(1); } + ret=BN_mod_exp_mont_consttime(r_mont_const,a,b,m,ctx,NULL); + if (ret <= 0) + { + printf("BN_mod_exp_mont_consttime() problems\n"); + ERR_print_errors(out); + EXIT(1); + } + if (BN_cmp(r_simple, r_mont) == 0 - && BN_cmp(r_simple,r_recp) == 0) + && BN_cmp(r_simple,r_recp) == 0 + && BN_cmp(r_simple,r_mont_const) == 0) { printf("."); fflush(stdout); @@ -153,6 +163,8 @@ int main(int argc, char *argv[]) { if (BN_cmp(r_simple,r_mont) != 0) printf("\nsimple and mont results differ\n"); + if (BN_cmp(r_simple,r_mont) != 0) + printf("\nsimple and mont const time results differ\n"); if (BN_cmp(r_simple,r_recp) != 0) printf("\nsimple and recp results differ\n"); @@ -162,11 +174,13 @@ int main(int argc, char *argv[]) printf("\nsimple ="); BN_print(out,r_simple); printf("\nrecp ="); BN_print(out,r_recp); printf("\nmont ="); BN_print(out,r_mont); + printf("\nmont_ct ="); BN_print(out,r_mont_const); printf("\n"); EXIT(1); } } BN_free(r_mont); + BN_free(r_mont_const); BN_free(r_recp); BN_free(r_simple); BN_free(a); |