Computes a scalar offset and adds it to another existing one
| 348 | |
| 349 | // Computes a scalar offset and adds it to another existing one |
| 350 | bool ComputeAndAddToScalarOffset(uint256& a, CAmount value, const uint256& asset_blinder, const uint256& value_blinder) |
| 351 | { |
| 352 | // If both asset and value blinders are null, 0 is added to the offset, so nothing actually happens |
| 353 | if (asset_blinder.IsNull() && value_blinder.IsNull()) return true; |
| 354 | |
| 355 | uint256 scalar; |
| 356 | if (!CalculateScalarOffset(scalar, value, asset_blinder, value_blinder)) return false; |
| 357 | |
| 358 | // When we start out, the result (a) is 0, so just set it to the scalar we just computed. |
| 359 | if (a.IsNull()) { |
| 360 | a = scalar; |
| 361 | } else { |
| 362 | uint256 scalar_negated = scalar; |
| 363 | if (secp256k1_ec_seckey_negate(secp256k1_blind_context, scalar_negated.begin()) != 1) { |
| 364 | return false; |
| 365 | } |
| 366 | // Special-case zero, which would otherwise cause `secp256k1_ec_seckey_tweak_add` to fail |
| 367 | if (scalar_negated == a) { |
| 368 | a = uint256{}; |
| 369 | } else { |
| 370 | // If we have a, then add the scalar to it. |
| 371 | if (secp256k1_ec_seckey_tweak_add(secp256k1_blind_context, a.begin(), scalar.begin()) != 1) return false; |
| 372 | } |
| 373 | } |
| 374 | return true; |
| 375 | } |
| 376 | |
| 377 | BlindingStatus BlindPSBT(PartiallySignedTransaction& psbt, std::map<uint32_t, std::tuple<CAmount, CAsset, uint256, uint256>> our_input_data, std::map<uint32_t, std::pair<CKey, CKey>> our_issuances_to_blind) |
| 378 | { |
no test coverage detected