frost/secp256k1-zkp
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Comment copyediting.

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This commit is contained in:
Gregory Maxwell
2015-10-31 08:31:15 +00:00
parent b4d17da903
commit 269d422703
6 changed files with 21 additions and 16 deletions
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13
src/ecdsa_impl.h
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@@ -75,8 +75,9 @@ static int secp256k1_der_read_len(const unsigned char **sigp, const unsigned cha
return -1;
}
if ((size_t)lenleft > sizeof(size_t)) {
/* The resulthing length would exceed the range of a size_t, so
certainly longer than the passed array size. */
/* The resulting length would exceed the range of a size_t, so
* certainly longer than the passed array size.
*/
return -1;
}
while (lenleft > 0) {
@@ -267,13 +268,17 @@ static int secp256k1_ecdsa_sig_sign(const secp256k1_ecmult_gen_context *ctx, sec
secp256k1_fe_get_b32(b, &r.x);
secp256k1_scalar_set_b32(sigr, b, &overflow);
if (secp256k1_scalar_is_zero(sigr)) {
/* P.x = order is on the curve, so technically sig->r could end up zero, which would be an invalid signature. */
/* This branch is cryptographically unreachable as hitting it requires finding the discrete log of P.x = N. */
/* P.x = order is on the curve, so technically sig->r could end up zero, which would be an invalid signature.
* This branch is cryptographically unreachable as hitting it requires finding the discrete log of P.x = N.
*/
secp256k1_gej_clear(&rp);
secp256k1_ge_clear(&r);
return 0;
}
if (recid) {
/* The overflow condition is cryptographically unreachable as hitting it requires finding the discrete log
* of some P where P.x >= order, and only 1 in about 2^127 points meet this criteria.
*/
*recid = (overflow ? 2 : 0) | (secp256k1_fe_is_odd(&r.y) ? 1 : 0);
}
secp256k1_scalar_mul(&n, sigr, seckey);