LatticePay Specification

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LatticePay

Tools for Trade, Not Surveillance.

LatticePay is an open-source payment infrastructure specification designed to provide private, encrypted, local-first commerce without unnecessary surveillance, centralized data control, or vendor lock-in.

LatticePay is designed as infrastructure rather than a centralized payment service. It enables merchants, developers, organizations, and communities to operate payment systems under their own control while supporting interoperable payment rails, distributed operation, and offline commerce.

Purpose

LatticePay is designed to establish an open foundation for payment and commerce systems that:

Protect transaction and merchant data through encryption by default
Support local-first and offline-capable commerce
Give merchants control over their payment infrastructure and transaction records
Support multiple payment and settlement methods through modular plugins
Enable peer-to-peer and federated commerce infrastructure
Minimize unnecessary collection and exposure of sensitive information
Provide verifiable transaction records without requiring centralized surveillance
Avoid proprietary payment infrastructure lock-in
Support extensibility for future payment technologies
Preserve transparency through open-source development and auditable protocols

Core Modules

Payment Processing Module

The Payment Processing Module provides the mechanisms required to initiate, authorize, record, reconcile, refund, and reverse payment transactions.

Features include:

Tap payment support
QR payment support
Invoice-based payments
Manual payment entry
Payment authorization
Payment confirmation
Transaction status tracking
Real-time settlement support
Deferred settlement support
Partial payment processing
Split tender payments
Merchant-to-merchant payments
Refund processing
Reversal processing
Cryptographic linkage between related transactions
Multi-currency transaction support
Offline transaction creation
Offline transaction signing
Transaction reconciliation
Duplicate transaction detection
Transaction state validation

Encryption & Privacy Module

The Encryption & Privacy Module protects sensitive commerce information throughout the transaction lifecycle.

Features include:

End-to-end encryption by default
Client-side encryption before transmission
Encrypted transaction payloads
Encrypted receipts
Encrypted merchant records
Encrypted customer information where retained
Forward-secret session keys
Cryptographic key rotation
Cryptographic identity
Digital signatures
Secure key management
Data minimization
Optional pseudonymous transaction identities
Optional privacy-preserving payment validation
Protection against unauthorized transaction disclosure
Separation of transaction authorization from unnecessary personal information

The system is designed so that encryption is a foundational property of the protocol rather than an optional add-on.

Identity & Authorization Module

The Identity & Authorization Module provides cryptographic identities and access controls without requiring a centralized identity provider.

Features include:

Cryptographic merchant identities
Cryptographic device identities
Cryptographic user identities where required
Digital signatures
Device authorization
Merchant authorization
Role-based permissions
Key-based access control
Key rotation
Credential revocation
Multi-device authorization
Delegated authorization
Session authentication
Optional pseudonymous identities

Identity information should only be collected or retained when required for the applicable transaction, payment rail, legal obligation, or merchant-selected function.

Local-First Commerce Module

The Local-First Commerce Module enables LatticePay to operate without continuous access to a centralized server.

Features include:

Local transaction processing
Local transaction storage
Offline POS operation
Offline payment workflows where supported by the selected payment rail
Local receipt generation
Local inventory access
Local merchant administration
Deferred synchronization
Automatic synchronization when connectivity returns
Local recovery mechanisms
Operation during temporary network outages
Merchant-controlled local data

Local operation is treated as a core architectural capability rather than a fallback mode.

Ledger & Accounting Module

The Ledger & Accounting Module provides a deterministic record of commerce activity.

Features include:

Append-only transaction records
Transaction timestamps
Transaction identifiers
Transaction state history
Cryptographic transaction signatures
Tamper-evident records
Hash-linked transaction relationships
Deterministic reconciliation
Multi-device ledger synchronization
Account and balance tracking
Refund and reversal linkage
Merchant-controlled accounting records
Accounting data export
Transaction history search
Financial reporting support
Audit trail generation

The ledger is designed to preserve transaction integrity while limiting unnecessary disclosure of transaction information.

Synchronization Module

The Synchronization Module coordinates commerce data across authorized devices and nodes.

Features include:

Local-to-local synchronization
Device-to-device synchronization
Merchant node synchronization
Offline synchronization
Conflict detection
Conflict resolution
Distributed state reconciliation
Deterministic state convergence
Encrypted synchronization
Selective synchronization
Authorized peer discovery
Recovery after interrupted synchronization

Synchronization must preserve transaction integrity and must not require exposing plaintext transaction data to unauthorized infrastructure.

Network & Federation Module

The Network & Federation Module provides decentralized communication and optional federation between independently operated LatticePay systems.

Features include:

Peer-to-peer communication
Encrypted node communication
Merchant-controlled nodes
Community-operated nodes
Federated merchant networks
Authorized peer relationships
Node discovery
Node authentication
Secure synchronization
Network resilience
Interoperable federation
Independent deployment
Optional disconnected operation

Federation is optional. A merchant must be able to operate independently without joining a shared network.

POS & Merchant Operations Module

The POS & Merchant Operations Module provides the operational tools required to conduct everyday commerce.

Features include:

Point-of-sale transaction processing
Product entry
Product lookup
Cart management
Tax calculation
Discounts
Customer-selected payment methods
Receipt generation
Refund processing
Transaction lookup
Cash drawer support
Register management
Multi-register operation
Multi-device operation
Merchant administration
Employee permissions
Shift management
Sales summaries
Daily transaction summaries
Offline operation

Inventory Module

The Inventory Module provides merchant inventory management capabilities.

Features include:

Product records
Product identifiers
Product pricing
Stock quantities
Inventory adjustments
Low-stock indicators
Inventory synchronization
Product categories
Product search
Stock movement history
Inventory reporting
Multi-location inventory support
Optional integration with external inventory systems

Invoicing Module

The Invoicing Module provides encrypted invoice creation and payment tracking.

Features include:

Invoice creation
Invoice numbering
Line-item management
Tax and discount calculations
Payment status tracking
Partial invoice payments
Invoice expiration
Encrypted invoice delivery
Digital receipts
Invoice history
Refund linkage
Merchant-controlled invoice records
Exportable invoice records

Receipt & Commerce Records Module

The Receipt & Commerce Records Module manages transaction documentation.

Features include:

Digital receipts
Encrypted receipts
Printable receipts
Receipt delivery
Receipt verification
Transaction-linked receipts
Refund receipts
Invoice-linked receipts
Merchant-controlled receipt storage
Customer-selected receipt delivery methods
Exportable transaction documentation

Merchant Data Ownership Module

The Merchant Data Ownership Module establishes merchant control over operational and transaction data.

Features include:

Merchant-controlled data storage
Local data ownership
Encrypted records
Data export
Data portability
Data deletion controls where legally and technically appropriate
Selective data sharing
Access controls
No mandatory centralized analytics
No behavioral profiling
No data brokerage
No required third-party data warehouse

Security & Audit Module

The Security & Audit Module provides mechanisms for detecting unauthorized changes and reviewing system activity.

Features include:

Cryptographically verifiable transactions
Tamper-evident records
Signed events
Security event logging
Authorization event logging
Administrative audit trails
Integrity verification
Transaction verification
Key lifecycle auditing
Reconciliation auditing
Exportable audit records
Privacy-preserving audit capabilities

Audit functionality must avoid creating unnecessary centralized surveillance of merchants or customers.

Optional Plugin Modules

LatticePay uses a modular plugin model so payment rails, settlement systems, and specialized commerce capabilities can be added without modifying the core protocol.