How SSP Components Work Together

The Complete SSP Ecosystem

SSP consists of three core components working together to provide secure, user-friendly cryptocurrency management using traditional 2-of-2 multisignature technology:

graph TB
    subgraph "User Devices"
        A[SSP Wallet<br/>Browser Extension<br/>Private Key #1]
        B[SSP Key<br/>Mobile App<br/>Private Key #2]
    end
    
    subgraph "Infrastructure"
        C[SSP Relay<br/>Optional Communication Server<br/>Zero-Knowledge Design]
    end
    
    subgraph "Blockchain Networks"
        D[Bitcoin/UTXO Networks<br/>P2SH/P2WSH Multisig]
        E[Ethereum/EVM Networks<br/>EOA + Schnorr Signing]
        F[15+ Other Blockchains]
    end
    
    A <--> C
    B <--> C
    A --> D
    A --> E
    A --> F
    B --> D
    B --> E
    B --> F
    
    style A fill:#4CAF50
    style B fill:#2196F3
    style C fill:#FF9800
    style D fill:#FF5722
    style E fill:#9C27B0

Component Deep Dive

🌐 SSP Wallet (Browser Extension)

Primary Key Holder & User Interface

Purpose: Main interface for wallet management and transaction initiation
Key Role: Holds first private key (Key #1) of the 2-of-2 multisig pair
Platforms: Chrome, Firefox, Brave, Edge
Built With: React 19, TypeScript, Vite
Architecture: Manifest v3 browser extension

Core Responsibilities:

👤 User interface for all wallet operations across 15+ blockchains
🔑 Generate and securely store first BIP48-derived private key
💸 Construct transactions for UTXO and EVM networks
🔄 Coordinate with SSP Key for transaction approval
🌍 Multi-blockchain support with network-specific optimizations
🔗 WalletConnect v2 integration for dApp connectivity

Supported Address Types:

Bitcoin/UTXO: P2SH, P2WSH (SegWit) multisignature addresses
Ethereum/EVM: Standard EOA addresses with Schnorr multisig message signing
Account Abstraction: Optional smart contract wallets on EVM chains

📱 SSP Key (Mobile App)

Secondary Key Holder & Transaction Authorizer

Purpose: Secure mobile 2FA device for transaction authorization
Key Role: Holds second private key (Key #2) of the 2-of-2 multisig pair
Platforms: iOS 15.1+, Android 7+
Built With: React Native 0.78, TypeScript
Security: React Native Keychain + MMKV encrypted storage

Core Responsibilities:

🔐 Generate and store second BIP48-derived private key independently
✅ Review transaction details and approve/reject on mobile interface
📱 Receive push notifications for transaction requests (FCM/APNS)
🔄 Synchronize with SSP Wallet via QR codes or optional relay server
📤 Complete multisignature transactions using Schnorr signatures
🛡️ Independent security layer with biometric authentication

Key Security Features:

iOS: Keychain Services integration with Face ID/Touch ID
Android: Android Keystore with fingerprint authentication
Encryption: AES-256 with device fingerprinting
Offline Capable: Full functionality via QR code scanning

⚡ SSP Relay (Communication Server)

Optional Zero-Knowledge Communication Bridge

Purpose: Optional server to facilitate communication between devices
Key Role: Message relay only - never accesses or stores private keys
Infrastructure: Node.js 20+, MongoDB, WebSocket, REST API
Security: Zero-knowledge architecture, end-to-end encryption
Alternative: Full offline operation available via QR codes

Core Responsibilities:

📡 Relay encrypted messages between SSP Wallet and SSP Key
🔄 Coordinate device synchronization process (optional)
📊 Provide blockchain data, network fees, and UTXO information
🌐 Support for 15+ blockchain networks via various APIs
🚀 WebSocket connections for real-time communication
📈 Caching and performance optimization

Zero-Knowledge Design:

❌ Never sees: Private keys, seed phrases, transaction details
✅ Only handles: Encrypted message passing and public blockchain data
✅ Alternative: Users can operate completely offline with QR codes

Communication Flow

Initial Setup & Synchronization

Online Synchronization (via SSP Relay)

SSP Wallet                SSP Relay (Optional)       SSP Key
    |                         |                         |
    |--- Generate QR Code ---->|                         |
    |    (Contains xPub)       |<--- Scan QR Code -------|
    |                         |   (Extract xPub)        |
    |<-- Exchange xPubs -------|<-- Exchange xPubs ------|
    |                         |                         |
    |<-- Generate Multisig --->|<-- Generate Multisig -->|
    |    Addresses (BIP48)     |    Addresses (BIP48)    |
    |                         |                         |
    |--- Sync Confirmed ------>|--- Sync Confirmed ----->|

Offline Synchronization (QR Code Only)

SSP Wallet                                    SSP Key
    |                                           |
    |--- Display QR Code (xPub) -------------->|
    |                                           |
    |<-- Display QR Code (xPub) ---------------|
    |                                           |
    |--- Both devices generate identical ------|
    |    multisig addresses using BIP48        |

Transaction Process

Online Transaction Flow

SSP Wallet                SSP Relay                SSP Key
    |                         |                         |
    |--- Create Transaction -->|                         |
    |    (UTXO or EVM)         |--- Push Notification -->|
    |    Signed with Key #1    |                         |
    |                         |<-- User Reviews Tx -----|
    |                         |<-- Signs with Key #2 ---|
    |<-- Complete Multisig ---|                         |
    |    Transaction           |                         |
    |--- Broadcast to Network->|                         |

Offline Transaction Flow

SSP Wallet                                    SSP Key
    |                                           |
    |--- Display Unsigned Tx QR Code --------->|
    |                                           |
    |<-- Display Signed Tx QR Code ------------|
    |                                           |
    |--- Scan, Combine, & Broadcast Tx -------|

Security Architecture

🔐 Traditional Multisignature Security

True 2-of-2: Both private keys required for every transaction
BIP48 Derivation: Industry-standard hierarchical deterministic keys
Network Native: Uses each blockchain's native multisig capabilities
No Single Point of Failure: Compromise of one device doesn't affect funds

🛡️ Device-Level Protection

SSP Wallet: Browser extension with encrypted local storage
SSP Key: Mobile app with hardware-backed key storage
Communication: Optional relay server with zero-knowledge design
Backup: User-controlled seed phrase backup (no cloud storage)

🔄 Redundant Verification

Address validation on both devices during setup
Transaction details verification before signing
Network-specific validation before broadcast
Optional offline operation for maximum security

Data Flow & Storage

SSP Wallet Storage (Browser Extension)

✅ Encrypted with AES-256: BIP48 private key with password-based encryption
✅ Device Fingerprinted: Encryption tied to specific browser and device
✅ Local Storage: Transaction history, contacts via LocalForage
✅ Session Storage: Temporary password caching for user convenience
✅ No Cloud Sync: All data remains on user's local device

SSP Key Storage (Mobile App)

✅ React Native Keychain: iOS Keychain Services/Android Keystore
✅ MMKV Encrypted: High-performance encrypted local database
✅ Device-Specific Encryption: Uses device fingerprint + user PIN/biometric
✅ Biometric Integration: Face ID/Touch ID/Fingerprint authentication
✅ User-Controlled Backup: Seed phrase backup managed by user

SSP Relay Storage (Zero-Knowledge)

❌ No Private Keys: Never sees, stores, or accesses private keys
❌ No Seed Phrases: No access to wallet recovery information
✅ Message Queue: Temporary encrypted message passing only
✅ Blockchain Data: Public UTXO and network information caching
✅ Performance Data: Network fees and transaction estimation

Integration Points

Blockchain Networks (Actual Implementation)

Based on /src/storage/blockchains.ts:

UTXO Networks (Native Multisignature)

Bitcoin: P2WSH multisig addresses, RBF support, SegWit optimization
Litecoin: P2WSH multisig, 2.5-minute blocks, low fees
Dogecoin: P2SH multisig, high throughput, meme-friendly
Bitcoin Cash: P2SH multisig, cashaddr format, BCH-specific features
Ravencoin: P2SH multisig, asset creation and transfers
Zcash: P2SH multisig, transparent addresses (shielded coming)
Flux: P2SH multisig, native integration with Flux ecosystem

EVM Networks (EOA + Schnorr Signing)

Ethereum (Chain ID: 1): Schnorr multisig message signing, Account Abstraction
Polygon (Chain ID: 137): Low-cost transactions, full EVM compatibility
BSC (Chain ID: 56): High throughput, Binance ecosystem integration
Base (Chain ID: 8453): Coinbase L2, optimized user experience
Avalanche (Chain ID: 43114): Sub-second finality, C-Chain compatibility

External Service Integration

WalletConnect v2: Full protocol support with Schnorr multisig compatibility
Onramper: Integrated fiat-to-crypto onramp services
Blockbook/Insight: UTXO network APIs for Bitcoin-like chains
Alchemy: Premium Ethereum infrastructure provider
Etherspot: Account Abstraction bundler services

Performance Characteristics

Network-Specific Optimization

UTXO Networks: Efficient UTXO selection and fee optimization
EVM Networks: Gas price optimization and transaction batching
Cross-Chain: Unified interface across different blockchain architectures

Scaling Capabilities

Concurrent Users: Thousands per relay instance
Transaction Throughput: Limited by blockchain networks, not SSP
Network Efficiency: Optimized API calls and caching strategies
Offline Operations: Full functionality without internet connectivity

Monitoring & Health

System Health Indicators

🟢 Device Sync Status: Real-time synchronization between wallet and key
🟢 Network Connectivity: Blockchain node and API endpoint health
🟢 Relay Server Status: Optional communication server availability
🟢 Transaction Queue: Pending and confirmed transaction status

Error Recovery Mechanisms

Automatic Reconnection: Network interruption handling
State Synchronization: Consistent state across devices and sessions
Offline Mode Activation: Seamless QR code fallback
Transaction Retry Logic: Failed transaction recovery procedures

Next Steps

Introduction to 2-of-2 Multisignature - Core security concepts
BIP48 Key Derivation Explained - Technical key generation details
Security Architecture Deep Dive - Comprehensive security analysis
Communication Protocol - Detailed communication flows

PreviousIntroduction to 2-of-2 Multisignature NextWalletConnect v2 Integration

Last updated 6 days ago