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Add scalar splitting functions

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Which currently delegate to the lambda-splitter in group.
This commit is contained in:
Pieter Wuille
2014-11-26 16:22:02 +01:00
parent d1502eb459
commit 6794be6080
4 changed files with 60 additions and 0 deletions
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23
src/scalar_impl.h
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@@ -198,4 +198,27 @@ static void secp256k1_scalar_inverse_var(secp256k1_scalar_t *r, const secp256k1_
#endif
}
#ifdef USE_ENDOMORPHISM
static void secp256k1_scalar_split_lambda_var(secp256k1_scalar_t *r1, secp256k1_scalar_t *r2, const secp256k1_scalar_t *a) {
unsigned char b[32];
secp256k1_scalar_get_b32(b, a);
secp256k1_num_t na;
secp256k1_num_set_bin(&na, b, 32);
secp256k1_num_t rn1, rn2;
secp256k1_gej_split_exp_var(&rn1, &rn2, &na);
secp256k1_num_get_bin(b, 32, &rn1);
secp256k1_scalar_set_b32(r1, b, NULL);
if (secp256k1_num_is_neg(&rn1)) {
secp256k1_scalar_negate(r1, r1);
}
secp256k1_num_get_bin(b, 32, &rn2);
secp256k1_scalar_set_b32(r2, b, NULL);
if (secp256k1_num_is_neg(&rn2)) {
secp256k1_scalar_negate(r2, r2);
}
}
#endif
#endif