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Add another bn modexp test.

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Add a test based on multiplication optimizations from OpenSSL HEAD
(1.1.0-dev) Based on openssl-SNAP-20111003
This commit is contained in:
Adam Langley 2014-06-20 12:00:00 -07:00
parent 520ed0446c
commit b36a3156b6
2 changed files with 73 additions and 4 deletions
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3
crypto/bn/bn.h
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@ -709,9 +709,6 @@ int BN_mod_exp_mont_word(BIGNUM *r, BN_ULONG a, const BIGNUM *p,
int BN_mod_exp2_mont(BIGNUM *r, const BIGNUM *a1, const BIGNUM *p1,
const BIGNUM *a2, const BIGNUM *p2, const BIGNUM *m,
BN_CTX *ctx, BN_MONT_CTX *m_ctx);
int BN_mod_exp_simple(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
const BIGNUM *m, BN_CTX *ctx);
/* Private functions */

74
crypto/bn/bn_test.c
View File

@ -98,6 +98,7 @@ int test_mod_exp(BIO *bp, BN_CTX *ctx);
int test_mod_exp_mont_consttime(BIO *bp, BN_CTX *ctx);
int test_exp(BIO *bp, BN_CTX *ctx);
int test_mod_sqrt(BIO *bp, BN_CTX *ctx);
int test_mod_exp_mont5(BIO *bp, BN_CTX *ctx);
#if 0
int test_gf2m_add(BIO *bp);
int test_gf2m_mod(BIO *bp);
@ -243,8 +244,10 @@ int main(int argc, char *argv[]) {
(void)BIO_flush(out);
message(out, "BN_mod_exp_mont_consttime");
if (!test_mod_exp_mont_consttime(out, ctx))
if (!test_mod_exp_mont_consttime(out, ctx) ||
!test_mod_exp_mont5(out, ctx)) {
goto err;
}
(void)BIO_flush(out);
message(out, "BN_exp");
@ -1000,6 +1003,75 @@ int test_mod_exp_mont_consttime(BIO *bp, BN_CTX *ctx) {
return (1);
}
/* Test constant-time modular exponentiation with 1024-bit inputs,
* which on x86_64 cause a different code branch to be taken. */
int test_mod_exp_mont5(BIO *bp, BN_CTX *ctx) {
BIGNUM *a, *p, *m, *d, *e;
BN_MONT_CTX *mont;
a = BN_new();
p = BN_new();
m = BN_new();
d = BN_new();
e = BN_new();
mont = BN_MONT_CTX_new();
BN_rand(m, 1024, 0, 1); /* must be odd for montgomery */
/* Zero exponent */
BN_rand(a, 1024, 0, 0);
BN_zero(p);
if (!BN_mod_exp_mont_consttime(d, a, p, m, ctx, NULL))
return 0;
if (!BN_is_one(d)) {
fprintf(stderr, "Modular exponentiation test failed!\n");
return 0;
}
/* Zero input */
BN_rand(p, 1024, 0, 0);
BN_zero(a);
if (!BN_mod_exp_mont_consttime(d, a, p, m, ctx, NULL))
return 0;
if (!BN_is_zero(d)) {
fprintf(stderr, "Modular exponentiation test failed!\n");
return 0;
}
/* Craft an input whose Montgomery representation is 1,
* i.e., shorter than the modulus m, in order to test
* the const time precomputation scattering/gathering.
*/
BN_one(a);
BN_MONT_CTX_set(mont, m, ctx);
if (!BN_from_montgomery(e, a, mont, ctx) ||
!BN_mod_exp_mont_consttime(d, e, p, m, ctx, NULL) ||
!BN_mod_exp(a, e, p, m, ctx)) {
return 0;
}
if (BN_cmp(a, d) != 0) {
fprintf(stderr, "Modular exponentiation test failed!\n");
return 0;
}
/* Finally, some regular test vectors. */
BN_rand(e, 1024, 0, 0);
if (!BN_mod_exp_mont_consttime(d, e, p, m, ctx, NULL))
return 0;
if (!BN_mod_exp(a, e, p, m, ctx))
return 0;
if (BN_cmp(a, d) != 0) {
fprintf(stderr, "Modular exponentiation test failed!\n");
return 0;
}
BN_MONT_CTX_free(mont);
BN_free(a);
BN_free(p);
BN_free(m);
BN_free(d);
BN_free(e);
return (1);
}
int test_exp(BIO *bp, BN_CTX *ctx) {
BIGNUM *a, *b, *d, *e, *one;
int i;