Transaction Authorization Protocol
A framework for secure, compliant, and flexible blockchain transaction authorization
The Transaction Authorization Protocol (TAP) enables secure, compliant, and flexible transaction authorization between parties before settlement on a blockchain. TAP creates a separate "authorization layer" that operates independently from the blockchain "settlement layer," allowing participants to exchange necessary information, perform risk assessments, and implement compliance checks before funds move.
Transaction Authorization Improvement Proposals (TAIPs)
TAIPs describe standards for the Transaction Authorization Protocol ecosystem.
Core TAIPs
TAIP-1: TAP and TAIP Purpose and Guidelines
ReviewEstablishes the Transaction Authorization Protocol (TAP) framework and defines the process for submitting Transaction Authorization Improvement Proposals (TAIPs). Specifies document formatting requirements, editorial workflow, and governance structure for TAP standard development.
TAIP-2: Messaging
ReviewImplements secure messaging between TAP agents using DIDComm v2, JSON encoding, and digital signatures via JWS with optional JWE encryption. Establishes required message attributes, transport protocols, and Out-of-Band invitation mechanisms to enable private, decentralized communication about digital asset transactions.
TAIP-3: Asset Transfer
ReviewDefines a chain-agnostic Transfer message format for moving digital assets between parties with standardized metadata for compliance and record-keeping. Specifies required JSON-LD fields including asset identifiers, amounts, originator/beneficiary information, and settlement details for both fungible and non-fungible tokens.
TAIP-4: Transaction Authorization Protocol
ReviewA protocol framework enabling off-chain authorization of blockchain transactions through DID-based agents before settlement. Separates transaction ordering, authorization, and settlement into distinct phases to address compliance, risk management, and operational challenges without changing permissionless blockchain characteristics.
TAIP-5: Transaction Agents
ReviewEstablishes Transaction Agents as services that execute transactions, including exchanges, wallets, and DeFi protocols, using DIDs for identification and authentication. Defines agent interaction protocols for adding, replacing, or removing agents in transaction flows, enabling collaboration between centralized and decentralized participants.
TAIP-6: Transaction Parties
ReviewDefines Transaction Parties as the real-world legal or natural persons involved in blockchain transactions, identified using IRIs or DIDs. Establishes party relationships with agents, party metadata standards, and messaging protocols for securely sharing party information while preserving privacy.
TAIP-7: Agent Policies
ReviewDefines a policy framework allowing transaction agents to declare their requirements for authorizing digital asset transfers using JSON-LD structured declarations. Establishes standardized policy types including authorization requirements, beneficiary checks, relationship confirmations, and credential presentations to enable trust and compliance in decentralized transaction ecosystems.
TAIP-8: Selective Disclosure
ReviewDefines a secure method for transaction agents to exchange verified credentials and personally identifiable information (PII) using W3C Verifiable Credentials and DIDComm encrypted messaging. Enables regulatory compliance with data protection laws through selective disclosure that minimizes PII exposure and allows agents to verify transaction counterparties while maintaining privacy.
TAIP-9: Proof of Relationship
ReviewEstablishes methods for verifying relationships between transaction participants, particularly proving control of blockchain addresses by specific agents or parties. Enables both declarative confirmations and cryptographic proofs using CACAO signatures to verify wallet ownership for KYC, sanctions screening, and Travel Rule compliance.
TAIP-10: IVMS101 for Travel Rule Identity Verification in TAP
ReviewImplements FATF Travel Rule compliance by integrating IVMS-101 identity data exchange into TAP using existing policy and selective disclosure mechanisms. Enables secure sharing of counterparty identity information through both proactive and reactive approaches while maintaining privacy through minimal disclosure principles.
TAIP-11: Legal Entity Identifier (LEI) to Identify institutional participants in TAP Messages
ReviewIntegrates Legal Entity Identifiers (LEIs) into TAP messages to uniquely and unambiguously identify institutional participants like VASPs in digital asset transactions. Enables regulatory compliance and institutional recognition without exchanging full identity profiles, maintaining TAP's lightweight and privacy-preserving approach to entity verification.
TAIP-12: Hashed Participant Name sharing in TAP messages
ReviewDefines an optional SHA-256 hashed name field for originator and beneficiary party data, enabling identity verification without exposing personal information in plaintext. Provides Travel Rule compliance while preserving privacy through a standardized hashing method compatible with VerifyVASP and GTR networks.
TAIP-13: Transaction Purpose Codes
ReviewAdds standardized ISO 20022 purpose and categoryPurpose fields to Asset Transfer messages, enabling clear indication of payment reasons and improved interoperability with traditional financial systems. Defines a RequirePurpose policy allowing agents to mandate purpose codes for regulatory compliance while maintaining backward compatibility.
TAIP-14: Payments
ReviewDefines a merchant-initiated Payment message standard for requesting blockchain payments with specified amounts in either crypto assets or fiat currencies. Enables selective disclosure of customer information for compliance and business purposes while facilitating standard e-commerce and invoice payment flows with privacy protection.
TAIP-15: Agent Connection Protocol
DraftEstablishes a protocol for creating secure, authorized connections between TAP agents with predefined transaction constraints and OAuth-style authorization flows. Enables persistent B2B integrations with transaction limits, purpose restrictions, and user control mechanisms for ongoing business relationships while maintaining robust risk management.
TAIP-16: Invoices
DraftDefines a structured Invoice object format for embedding detailed payment information with line items and tax data in TAIP-14 Payment Requests. Maps to established standards like UBL and W3C Payment Request for interoperability with existing business systems while supporting regulatory compliance requirements.