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| author | Bodo Möller <bodo@openssl.org> | 2001-03-11 08:44:50 +0000 |
|---|---|---|
| committer | Bodo Möller <bodo@openssl.org> | 2001-03-11 08:44:50 +0000 |
| commit | 86a921af06f52d1b16fbc8a76d8f0ff1950d1c8a (patch) | |
| tree | ef61352f93abc72ab99295a318ad0b3a45f73b0e | |
| parent | 616df356332246c891fb1a650fef54ee211cafd3 (diff) | |
| download | openssl-86a921af06f52d1b16fbc8a76d8f0ff1950d1c8a.tar.gz | |
handle negative scalars correctly when doing point multiplication
| -rw-r--r-- | crypto/ec/ec_mult.c | 8 | ||||
| -rw-r--r-- | crypto/ec/ectest.c | 19 |
2 files changed, 25 insertions, 2 deletions
diff --git a/crypto/ec/ec_mult.c b/crypto/ec/ec_mult.c index ddd3db5921..01574d8c93 100644 --- a/crypto/ec/ec_mult.c +++ b/crypto/ec/ec_mult.c @@ -187,10 +187,18 @@ int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, BIGNUM *scalar, if (i < num) { if (!EC_POINT_copy(val_sub[i][0], points[i])) goto err; + if (scalars[i]->neg) + { + if (!EC_POINT_invert(group, val_sub[i][0], ctx)) goto err; + } } else { if (!EC_POINT_copy(val_sub[i][0], generator)) goto err; + if (scalar->neg) + { + if (!EC_POINT_invert(group, val_sub[i][0], ctx)) goto err; + } } if (wsize[i] > 1) diff --git a/crypto/ec/ectest.c b/crypto/ec/ectest.c index b68e27e98a..766a0dbc75 100644 --- a/crypto/ec/ectest.c +++ b/crypto/ec/ectest.c @@ -519,7 +519,7 @@ int main(int argc, char *argv[]) scalars[0] = y; /* (group order + 1)/2, so y*Q + y*Q = Q */ scalars[1] = y; - fprintf(stdout, "simultaneous multiplication ... "); + fprintf(stdout, "simultaneous multiplication ..."); fflush(stdout); /* z is still the group order */ @@ -528,7 +528,22 @@ int main(int argc, char *argv[]) if (0 != EC_POINT_cmp(group, P, R, ctx)) ABORT; if (0 != EC_POINT_cmp(group, R, Q, ctx)) ABORT; - fprintf(stdout, "ok\n\n"); + fprintf(stdout, "."); + fflush(stdout); + + if (!BN_pseudo_rand(y, BN_num_bits(y), 0, 0)) ABORT; + if (!BN_copy(z, y)) ABORT; + z->neg = 1; + + points[0] = Q; + points[1] = Q; + scalars[0] = y; + scalars[1] = z; + + if (!EC_POINTs_mul(group, P, NULL, 2, points, scalars, ctx)) ABORT; + if (!EC_POINT_is_at_infinity(group, P)) ABORT; + + fprintf(stdout, " ok\n\n"); } |