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MoreBC2

Wallet spend and PSBT RPC

CategoryDocumentationStatusSource-reviewed / Runtime-tested partialLast reviewed2026-09-12

Summary

Section titled “Summary”

This page covers BitcoinII wallet spend/funding/PSBT behavior centered on src/wallet/rpc/spend.cpp and the signing helpers it calls.

The broad wallet RPC structure remains Bitcoin-style, but BitcoinII Core v31.1.0 adds an important BitcoinII-specific requirement: wallet and PSBT signing must use the replay-protection signature-hash domain selected for the next block.

Spend-related commands can move funds. Runtime evidence cited here used only a fresh disposable wallet and isolated regtest environment.

Main command groups

Section titled “Main command groups”

Reviewed command families include:

  • direct sends: sendtoaddress, sendmany, send, sendall;
  • fee/funding: settxfee, fundrawtransaction, walletcreatefundedpsbt;
  • fee bumping: bumpfee, psbtbumpfee;
  • signing/PSBT: signrawtransactionwithwallet, walletprocesspsbt;
  • PSBT finalization/extraction paths used by wallet RPC.

v31 replay-protection integration

Section titled “v31 replay-protection integration”

Mainnet replay protection activates at height 57750 with fork/domain id 0x01324342.

CWallet::GetSighashForkId() obtains the domain appropriate for transactions targeting the next block. Wallet signing and PSBT handling propagate that value through signing/precomputation/finalization rather than relying on generic Bitcoin signature hashes.

A PSBT can therefore be syntactically valid while a third-party signer still produces unusable post-activation BC2 signatures if it ignores the BC2 replay domain.

External signer boundary

Section titled “External signer boundary”

The v31 external-signer path explicitly rejects the assumption that a generic external signer can safely sign post-fork BitcoinII without replay-protection sighash support.

MoreBC2 should not describe a hardware/external signer as compatible merely because it supports Bitcoin-format addresses or generic PSBT.

Runtime evidence — 2026-09-11

Section titled “Runtime evidence — 2026-09-11”

MoreBC2 executed a complete bounded PSBT lifecycle using BitcoinII Core v31.1.0 on Windows with a fresh disposable regtest data directory, zero peers, and a newly created descriptor wallet.

The successful path included:

  • createwallet;
  • getnewaddress;
  • local generatetoaddress funding;
  • getbalances;
  • walletcreatefundedpsbt;
  • decodepsbt;
  • walletprocesspsbt with complete = true;
  • finalizepsbt with complete = true;
  • decoderawtransaction;
  • testmempoolaccept with allowed = true;
  • local-only sendrawtransaction into the isolated regtest mempool.

The transaction used only disposable regtest funds. No existing wallet/data directory was opened, copied, rescanned, imported, unlocked, inspected, or spent from, and no public-network broadcast occurred.

See Windows v31.1.0 PSBT and replay-protection validation — 2026-09-11.

Runtime boundary

Section titled “Runtime boundary”

The regtest lifecycle proves the documented wallet/PSBT workflow under that isolated environment. It does not runtime-prove the mainnet replay-protection activation switch because regtest leaves replay protection disabled as shipped.

The mainnet domain propagation and activation boundary remain release-pinned source evidence.

Still unverified:

  • deterministic pre/post-fork signature vectors;
  • raw-RPC versus wallet-signing digest equivalence across activation;
  • external/hardware signer compatibility;
  • public-network transaction broadcast;
  • broad direct-send/fee-bump/backup/encryption workflows.

Operational implication

Section titled “Operational implication”

For services and exchanges, the safe default is to use current BitcoinII Core wallet/signing/PSBT code or independently implement and test BC2’s replay-domain rules. The compatibility boundary is signature-digest behavior, not merely address encoding.

Section titled “Related pages”

Sources

Section titled “Sources”

Pinned BitcoinII Core v31.1.0 paths include src/wallet/rpc/spend.cpp, wallet/scriptpubkeyman files, src/psbt.*, signing/interpreter paths, and the chain interface.

Canonical tag: https://github.com/Bitcoin-II/BitcoinII-Core/tree/v31.1.0

Verification

Section titled “Verification”

Status: Source-reviewed / Runtime-tested partial
Primary sources checked: BitcoinII Core v31.1.0 plus the 2026-09-11 isolated PSBT runtime record
Notes: Wallet/PSBT replay-domain propagation is source-backed and the ordinary isolated PSBT lifecycle is runtime-tested. Mainnet replay activation and third-party/external signing remain outside the runtime scope.