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use bn_is_zero and bn_is_equal where possible

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This commit is contained in:
Pavol Rusnak 2014-11-17 17:17:14 +01:00
parent df3606dd5e
commit 9469a64a0a
1 changed files with 3 additions and 17 deletions
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20
ecdsa.c
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@ -343,12 +343,7 @@ int ecdsa_sign_digest(const uint8_t *priv_key, const uint8_t *digest, uint8_t *s
// r = (rx mod n)
bn_mod(&R.x, &order256k1);
// if r is zero, we fail
for (i = 0; i < 9; i++) {
if (R.x.val[i] != 0) break;
}
if (i == 9) {
return 2;
}
if (bn_is_zero(&R.x)) return 2;
bn_inverse(&k, &order256k1);
bn_read_be(priv_key, da);
bn_multiply(&R.x, da, &order256k1);
@ -360,13 +355,8 @@ int ecdsa_sign_digest(const uint8_t *priv_key, const uint8_t *digest, uint8_t *s
da->val[8] += z.val[8];
bn_multiply(da, &k, &order256k1);
bn_mod(&k, &order256k1);
for (i = 0; i < 9; i++) {
if (k.val[i] != 0) break;
}
// if k is zero, we fail
if (i == 9) {
return 3;
}
if (bn_is_zero(&k)) return 3;
// if S > order/2 => S = -S
if (bn_is_less(&order256k1_half, &k)) {
@ -595,11 +585,7 @@ int ecdsa_verify_digest(const uint8_t *pub_key, const uint8_t *sig, const uint8_
bn_mod(&(res.x), &order256k1);
// signature does not match
for (i = 0; i < 9; i++) {
if (res.x.val[i] != r.val[i]) {
return 5;
}
}
if (!bn_is_equal(&res.x, &r)) return 5;
// all OK
return 0;