Function CreateBlindAssetProof

src/blindpsbt.cpp:155–189

Create an explicit value rangeproof which proves that the commitment commits to an explicit value

// Create an explicit value rangeproof which proves that the commitment commits to an explicit value
bool CreateBlindAssetProof(std::vector<unsigned char>& assetproof, const CAsset& asset, const CConfidentialAsset& asset_commit, const uint256& asset_blinder)
{
    const unsigned char zero32[32] = {0};
    secp256k1_surjectionproof proof;
    size_t input_index;
    secp256k1_generator asset_gen;
    secp256k1_generator blinded_asset_gen;
    secp256k1_fixed_asset_tag fixed_tag;
    memcpy(&fixed_tag, asset.begin(), 32);

    if (!secp256k1_generator_generate(secp256k1_blind_context, &asset_gen, asset.begin())) {
        return false;
    }
    if (secp256k1_generator_parse(secp256k1_blind_context, &blinded_asset_gen, asset_commit.vchCommitment.data()) == 0) {
        return false;
    }

    if (!secp256k1_surjectionproof_initialize(secp256k1_blind_context, &proof, &input_index, &fixed_tag, 1, 1, &fixed_tag, 1, zero32)) {
        return false;
    }
    assert(input_index == 0);

    if (!secp256k1_surjectionproof_generate(secp256k1_blind_context, &proof, &asset_gen, 1, &blinded_asset_gen, 0, zero32, asset_blinder.data())) {
        return false;
    }
    if (!secp256k1_surjectionproof_verify(secp256k1_blind_context, &proof, &asset_gen, 1, &blinded_asset_gen)) {
        return false;
    }

    size_t output_len = secp256k1_surjectionproof_serialized_size(secp256k1_blind_context, &proof);
    assetproof.resize(output_len);
    secp256k1_surjectionproof_serialize(secp256k1_blind_context, &assetproof[0], &output_len, &proof);
    assert(output_len == assetproof.size());
    return true;
}

bool VerifyBlindValueProof(CAmount value, const CConfidentialValue& conf_value, const std::vector<unsigned char>& proof, const CConfidentialAsset& conf_asset)
{