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Separate helper function for ec_pubkey_tweak_add

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This is in preparation for allowing code reuse by xonly tweak add functions
This commit is contained in:
Jonas Nick 2020-05-12 14:45:22 +00:00
parent 4cd2ee474d
commit 176bfb1110
1 changed files with 10 additions and 9 deletions
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19
src/secp256k1.c
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@ -631,25 +631,26 @@ int secp256k1_ec_privkey_tweak_add(const secp256k1_context* ctx, unsigned char *
return secp256k1_ec_seckey_tweak_add(ctx, seckey, tweak);
}
static int secp256k1_ec_pubkey_tweak_add_helper(const secp256k1_ecmult_context* ecmult_ctx, secp256k1_ge *p, const unsigned char *tweak) {
secp256k1_scalar term;
int overflow = 0;
secp256k1_scalar_set_b32(&term, tweak, &overflow);
return !overflow && secp256k1_eckey_pubkey_tweak_add(ecmult_ctx, p, &term);
}
int secp256k1_ec_pubkey_tweak_add(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const unsigned char *tweak) {
secp256k1_ge p;
secp256k1_scalar term;
int ret = 0;
int overflow = 0;
VERIFY_CHECK(ctx != NULL);
ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx));
ARG_CHECK(pubkey != NULL);
ARG_CHECK(tweak != NULL);
secp256k1_scalar_set_b32(&term, tweak, &overflow);
ret = !overflow && secp256k1_pubkey_load(ctx, &p, pubkey);
ret = secp256k1_pubkey_load(ctx, &p, pubkey);
memset(pubkey, 0, sizeof(*pubkey));
ret = ret && secp256k1_ec_pubkey_tweak_add_helper(&ctx->ecmult_ctx, &p, tweak);
if (ret) {
if (secp256k1_eckey_pubkey_tweak_add(&ctx->ecmult_ctx, &p, &term)) {
secp256k1_pubkey_save(pubkey, &p);
} else {
ret = 0;
}
secp256k1_pubkey_save(pubkey, &p);
}
return ret;