Architecture Overview
Architecture Overview
A deep dive into the transaction flow, system architecture, and security mechanisms.
A deep dive into the transaction flow, system architecture, and security mechanisms.
Transaction Flow
Transaction Flow
End-to-end process across merchant and user devices.
End-to-end process across merchant and user devices.
1. Merchant device constructs unsigned payload (amount, network parameters, recipent address)
1. Merchant device constructs unsigned payload (amount, network parameters, recipent address)
2. User signals payment intent authenticates through biometrics to enable transaction signing
2. User signals payment intent authenticates through biometrics to enable transaction signing
3. Unsigned payload is transmitted to the user device via NFC
3. Unsigned payload is transmitted to the user device via NFC
4. User device signs the transaction locally using the private key
4. User device signs the transaction locally using the private key
5. Signed transaction is returned to the merchant device via NFC
5. Signed transaction is returned to the merchant device via NFC
6. Merchant device broadcasts the signed transaction to the blockchain
6. Merchant device broadcasts the signed transaction to the blockchain
7. Transaction is confirmed on-chanin and TXID is retrieved
7. Transaction is confirmed on-chanin and TXID is retrieved
8. Confirmation is relayed back to both merchant and user devices
8. Confirmation is relayed back to both merchant and user devices
Executed through a contactless, tap-to-pay user experience.
Executed through a contactless, tap-to-pay user experience.
COMPONENTS
System Components
System Components
Four core components operate together the enable contactless, on‑chain transactions.
Four core components operate together the enable contactless, on‑chain transactions.
Merchant Device - Constructs payloads and broadcasts signed transacions
Merchant Device - Constructs payloads and broadcasts signed transacions
User Device - Authenticates users and signs transactions locally
User Device - Authenticates users and signs transactions locally
CTAP Orchestration Layer - Manages communication, validation, and transaction handling between devices
CTAP Orchestration Layer - Manages communication, validation, and transaction handling between devices
Blockchain Network - Processes transactions and provides on-chain settlement
Blockchain Network - Processes transactions and provides on-chain settlement
SDK Structure
SDK Structure
Two SDKs enable integration across merchant systems and user devices.
Two SDKs enable integration across merchant systems and user devices.
MERCHANT SDK
Merchant Integraion Layer
Integrated into POS systems and merchant software platforms.
Built for Android-based smart POS systems.
Built for Android-based smart POS systems.
Built using Kotlin.
Built using Kotlin.
Connects to CTAP backend APIs for transaction orchestration
Connects to CTAP backend APIs for transaction orchestration
Interfaces with merchant-side software for transaction initiation
Interfaces with merchant-side software for transaction initiation
USER SDK
Wallet Provider Integration Layer
Designed for integration into wallet applications across mobile platforms.
Built for Android and iOS systems
Built for Android and iOS systems
Built using Kotlin and Swift
Built using Kotlin and Swift
Connects to CTAP backend APIs for transaction orchestration
Connects to CTAP backend APIs for transaction orchestration
Interfaces with wallet provider-side software for authentication relay
Interfaces with wallet provider-side software for authentication relay
Backend Infrastructure
Backend Infrastructure
Supporting systems enabling coordination, execution, and reliability across the payment flow.
Supporting systems enabling coordination, execution, and reliability across the payment flow.
Backend coordination layer (TypeScript, Node.js) manages transaction orchestration and exposes the APIs used for system communication
Backend coordination layer (TypeScript, Node.js) manages transaction orchestration and exposes the APIs used for system communication
Transaction relay and confirmation layer ensures signed transactions are broadcast and tracked on‑chain
Transaction relay and confirmation layer ensures signed transactions are broadcast and tracked on‑chain
Data layer (PostgreSQL) supports transaction tracking, logging, and system analytics
Data layer (PostgreSQL) supports transaction tracking, logging, and system analytics
Cloud Infrastructure (AWS) enables scalable deployment with redundancy and high availability
Cloud Infrastructure (AWS) enables scalable deployment with redundancy and high availability
Modular backend design supports expansion across multiple digital asset ecoststems and blockchain networks
Modular backend design supports expansion across multiple digital asset ecoststems and blockchain networks
SECURITY
Security Mechanisms
Designed to ensure secure, non-custodial transaction execution.
Private keys remain on the user device and are never exposed
Private keys remain on the user device and are never exposed
Transaction signing occurs locally on the user device
Transaction signing occurs locally on the user device
Biometric authentication enables a time-limited signing window for a single transaction
Biometric authentication enables a time-limited signing window for a single transaction
Transaction details are defined by the merchant and validated before payload broadcast
Transaction details are defined by the merchant and validated before payload broadcast
No custody of funds or private keys at any point in the system
No custody of funds or private keys at any point in the system
Communication between devices is limited to unsigned and signed transactions only
Communication between devices is limited to unsigned and signed transactions only
System Design Principles
System Design Principles
Core principles guiding system architecture and implementation.
Core principles guiding system architecture and implementation.
Non-custodial design ensures private keys remain with the user at all times
Non-custodial design ensures private keys remain with the user at all times
Transaction authority is distributed between merchant and user devices
Transaction authority is distributed between merchant and user devices
Direct on-chain settlement without reliance on intermediaries
Direct on-chain settlement without reliance on intermediaries
Compliance and regulatory responsibility are handled primarily at partner level, with CTAP operating as a technology layer for transaction orchestration
Compliance and regulatory responsibility are handled primarily at partner level, with CTAP operating as a technology layer for transaction orchestration
Designed for compatability with existing payment infrastructure
Designed for compatability with existing payment infrastructure
Built around a contactless, tap-to-pay user experience
Built around a contactless, tap-to-pay user experience
Explore the Business Model
Explore the Business Model
A Contactless Payment Rail for Digital Assets
A Contactless Payment Rail for Digital Assets