Partially Signed Bitcoin Transaction (PSBT)

Overview

Partially Signed Bitcoin Transaction (PSBT) is a standardized Bitcoin data format that carries an unsigned or partly signed transaction together with metadata needed by wallets and signers to collaborate. A valid signature proves that the relevant signing authority approved a particular payload; it does not prove that the signer understood the request or that the request was economically safe. Payload interpretation and policy enforcement remain essential.

It is a coordination container, not a broadcastable final transaction until required signatures and final scripts are completed. It should be distinguished from Transaction Signing, Offline Signing, and Co-Signing. These concepts may interact in one workflow, but they identify different control points, records, or security assumptions.

Operationally, participants verify inputs, outputs, change, fees, derivation data, proprietary fields, signer scope, and the final transaction before broadcast. A production implementation should preserve the applicable blockchain network, asset or contract identifier, source and destination ownership, policy version, responsible roles, timestamps, transaction identifiers, and evidence used to authorize or reconcile the action. Exceptions should be visible in an operational queue rather than silently corrected.

The principal risk is that malicious metadata, inconsistent PSBT versions, hidden change, excessive fees, or signing the wrong copy can cause loss or coordination failure. Teams should test normal and exceptional paths, including delayed confirmations, reorgs, unavailable custodians, signing-device failure, stale permissions, incorrect network selection, fee spikes, duplicate requests, compromised user interfaces, and incomplete recovery data. High-value actions should be independently reviewed before execution.

For governance and audit, document the exact meaning of Partially Signed Bitcoin Transaction (PSBT) in the relevant wallet, custody platform, smart contract, or internal ledger. Confirm who can create, change, approve, pause, reverse, or recover the associated configuration. Monitoring should cover privileged access, policy changes, address and key lifecycle events, balance movements, failed transactions, reconciliation differences, and unresolved customer claims. This converts the term from a product label into a testable operational control.