Function VerifyWitnessProgram

src/script/interpreter.cpp:3287–3380

}

static bool VerifyWitnessProgram(const CScriptWitness& witness, int witversion, const std::vector<unsigned char>& program, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror, bool is_p2sh)
{
    CScript exec_script; //!< Actually executed script (last stack item in P2WSH; implied P2PKH script in P2WPKH; leaf script in P2TR)
    Span stack{witness.stack};
    ScriptExecutionData execdata;

    if (witversion == 0) {
        if (program.size() == WITNESS_V0_SCRIPTHASH_SIZE) {
            // BIP141 P2WSH: 32-byte witness v0 program (which encodes SHA256(script))
            if (stack.size() == 0) {
                return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_WITNESS_EMPTY);
            }
            const valtype& script_bytes = SpanPopBack(stack);
            exec_script = CScript(script_bytes.begin(), script_bytes.end());
            uint256 hash_exec_script;
            CSHA256().Write(exec_script.data(), exec_script.size()).Finalize(hash_exec_script.begin());
            if (memcmp(hash_exec_script.begin(), program.data(), 32)) {
                return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_MISMATCH);
            }
            return ExecuteWitnessScript(stack, exec_script, flags, SigVersion::WITNESS_V0, checker, execdata, serror);
        } else if (program.size() == WITNESS_V0_KEYHASH_SIZE) {
            // BIP141 P2WPKH: 20-byte witness v0 program (which encodes Hash160(pubkey))
            if (stack.size() != 2) {
                return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_MISMATCH); // 2 items in witness
            }
            exec_script << OP_DUP << OP_HASH160 << program << OP_EQUALVERIFY << OP_CHECKSIG;
            return ExecuteWitnessScript(stack, exec_script, flags, SigVersion::WITNESS_V0, checker, execdata, serror);
        } else {
            return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_WRONG_LENGTH);
        }
    } else if (witversion == 1 && program.size() == WITNESS_V1_TAPROOT_SIZE && !is_p2sh) {
        // BIP341 Taproot: 32-byte non-P2SH witness v1 program (which encodes a P2C-tweaked pubkey)
        if (!(flags & SCRIPT_VERIFY_TAPROOT)) return set_success(serror);
        if (stack.size() == 0) return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_WITNESS_EMPTY);
        if (stack.size() >= 2 && !stack.back().empty() && stack.back()[0] == ANNEX_TAG) {
            // Drop annex (this is non-standard; see IsWitnessStandard)
            const valtype& annex = SpanPopBack(stack);
            execdata.m_annex_hash = (CHashWriter(SER_GETHASH, 0) << annex).GetSHA256();
            execdata.m_annex_present = true;
        } else {
            execdata.m_annex_present = false;
        }
        execdata.m_annex_init = true;
        if (stack.size() == 1) {
            // Key path spending (stack size is 1 after removing optional annex)
            if (!checker.CheckSchnorrSignature(stack.front(), program, SigVersion::TAPROOT, execdata, serror)) {
                return false; // serror is set
            }
            return set_success(serror);
        } else {
            // Script path spending (stack size is >1 after removing optional annex)
            const valtype& control = SpanPopBack(stack);
            const valtype& script_bytes = SpanPopBack(stack);
            exec_script = CScript(script_bytes.begin(), script_bytes.end());
            if (control.size() < TAPROOT_CONTROL_BASE_SIZE || control.size() > TAPROOT_CONTROL_MAX_SIZE || ((control.size() - TAPROOT_CONTROL_BASE_SIZE) % TAPROOT_CONTROL_NODE_SIZE) != 0) {
                return set_error(serror, SCRIPT_ERR_TAPROOT_WRONG_CONTROL_SIZE);
            }
            execdata.m_tapleaf_hash = ComputeTapleafHash(control[0] & TAPROOT_LEAF_MASK, exec_script);