https://github.com/ZcashCommunityGrants/zcashcommunitygrants/issues/145#issue-3675403285
FLASH Bridge: Project Overview
Empowering Financial Freedom Through Privacy-Preserving Cross-Chain Technology
Our Mission
FLASH Bridge is building infrastructure for a private, decentralized financial system where users can move value across blockchains without sacrificing privacy or freedom. Financial transactions should be as private as cash while keeping the programmability and efficiency of blockchain.
Core Values
Privacy by Design
Privacy is fundamental to financial freedom. We implement multiple layers of privacy protection:
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Layer 1: Zcash Shielding - Zero-knowledge proofs that hide transaction amounts and participants
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Layer 2: Arcium MPC - Multi-party computation that encrypts all bridge operations
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Layer 3: Cryptographic Proofs - Institutional-grade verification without revealing sensitive data
Why it matters: Without privacy, every transaction becomes a permanent record that can be analyzed, censored, or used against you. True financial freedom requires the ability to transact privately.
Financial Freedom
We’re building tools that give users control over their assets and transactions:
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Permissionless Access - No KYC, no gatekeepers, no approval processes
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Cross-Chain Sovereignty - Move value between Bitcoin, Zcash, and Solana seamlessly
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User Control - Your keys, your assets, your privacy
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Censorship Resistance - No single entity can block or reverse transactions
Why it matters: Financial freedom means the ability to transact with anyone, anywhere, without asking permission. It means your money is truly yours.
Security Through Cryptography
We use cryptographic proofs, not trust:
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Zero-Knowledge Verification - Prove transactions are valid without revealing details
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Multi-Party Computation - No single party can see or control the full transaction
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Cryptographic Signatures - Institutional-grade key management and verification
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Merkle Proofs - Mathematical guarantees of transaction inclusion
Why it matters: Trust is a vulnerability. Cryptography provides mathematical guarantees that don’t depend on trusting any individual or organization.
What We’ve Built
Phase 1: Foundation (Completed)
Multi-Chain Bridge Infrastructure
Bitcoin Integration
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Real Bitcoin transaction verification via explorer APIs
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Support for testnet4 and mainnet networks
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Automatic deposit detection and monitoring
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Small amount handling (0.0001 BTC support)
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Configurable confirmation requirements
Zcash Integration
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Shielded transaction verification
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Lightwalletd integration for real Zcash operations (testing only, PDA for production)
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Zcash Explorer API integration
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Price fetching and address validation
Solana Integration
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Native ZEC token support (official Solana ZEC)
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Jupiter DEX integration for token swaps (future plans of PDA treasury rate based swaps)
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Treasury management system
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Event-driven relayer architecture
Privacy Architecture
Arcium MPC Framework
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Custom MXE (Multi-Execution Environment) implementation
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Encrypted bridge amount operations
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Private transaction verification
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Trustless random generation
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Confidential swap calculations
Cryptographic Proof System
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HMAC-SHA256 signatures with institutional key management
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Merkle tree proofs for transaction inclusion
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Chain of custody tracking
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Audit trail capabilities
Backend Infrastructure
19 API Endpoints
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Bridge operations (mint, burn, swap)
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Multi-chain verification (BTC, ZEC)
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Privacy operations (encryption, decryption)
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Transaction status and history
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Health monitoring and status
Production-Ready Features
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Crash prevention with comprehensive error handling
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Circuit breaker protection against API failures
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Database persistence (PostgreSQL)
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Health monitoring and automatic recovery
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Retry logic with exponential backoff
Frontend Application
Modern React UI
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Solana Wallet Adapter integration (Phantom, Solflare)
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WebZjs integration for Zcash wallet support
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Real-time transaction status
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Responsive design
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Wallet persistence (localStorage)
Testing & Quality
Comprehensive Test Suite
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Unit tests for core services
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Integration tests for multi-chain flows
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End-to-end workflow validation
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Automated demo testing scripts
Documentation
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13+ comprehensive guides (7,000+ lines)
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Complete API documentation
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Setup and deployment instructions
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Security assessments
Phase 2: Current Development (In Progress)
Bitcoin Testnet4 Integration
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Configured testnet4 network support
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Bridge address monitoring system
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Small amount deposit handling (0.0001 BTC)
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Real-time deposit detection
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Automated processing pipeline
Enhanced User Experience
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Wallet persistence across sessions
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Import wallet from private keys (WIF format)
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Improved bridge flow automation
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Real-time status updates
What We’re Trying to Accomplish
Vision: The Private Financial Internet
We envision a world where:
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Anyone can bridge assets privately - Move Bitcoin to Solana without revealing amounts or participants
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No trusted intermediaries - Cryptographic proofs replace trust in third parties
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Censorship-resistant infrastructure - No entity can block or reverse transactions
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Programmable privacy - Use private assets in DeFi without sacrificing privacy
Short-Term Goals (Next 3-6 Months)
1. Production-Ready Bridge
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Complete security audit
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Multi-sig authority implementation
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Rate limiting and DDoS protection
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Comprehensive test coverage (>80%)
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Production infrastructure setup
2. Enhanced Privacy Features
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Full Halo2 ZK proof verification
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Advanced MPC operations
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Encrypted address handling
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Private relayer selection
3. User Experience Improvements
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Automated bridge flow (connect wallet → send → auto-process)
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Unique deposit addresses per request
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Real-time status tracking
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Mobile wallet support
4. Additional Chain Support
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Ethereum/EVM chain integration
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More Solana token options
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Cross-chain liquidity pools
Long-Term Vision (1-2 Years)
The Private DeFi Ecosystem
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Private Lending - Borrow against private assets
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Private Swaps - Trade without revealing positions
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Private Yield Farming - Earn yield while maintaining privacy
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Private Governance - Vote on proposals without revealing holdings
Institutional Adoption
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Compliance tools that prove validity without revealing details
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Enterprise-grade key management
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Regulatory-friendly privacy features
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Institutional proof generation
Global Financial Freedom
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Enable financial services in censored regions
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Protect users from financial surveillance
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Enable private remittances
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Support for privacy-focused economies
Technical Architecture
Three-Layer Privacy Model
┌─────────────────────────────────────────────────┐
│ Layer 1: Zcash Shielding │
│ - Zero-knowledge proofs │
│ - Shielded transaction support │
│ - Amount and participant privacy │
└─────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────┐
│ Layer 2: Arcium MPC │
│ - Multi-party computation │
│ - Encrypted bridge operations │
│ - Private verification │
│ - Trustless random generation │
└─────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────┐
│ Layer 3: Solana Security │
│ - Access controls │
│ - Transaction limits │
│ - Event-driven architecture │
│ - Programmable privacy │
└─────────────────────────────────────────────────┘
Bridge Flow
Bitcoin Payment
↓
[Zcash Shielding] → Private ZEC
↓
[MPC Encryption] → Encrypted Bridge Amount
↓
[Solana Transfer] → Native ZEC Token
↓
[Jupiter Swap] → User’s Desired Token
Why FLASH Bridge Matters
The Problem We’re Solving
Current State:
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Most bridges require KYC and reveal all transaction details -
Cross-chain transactions are transparent and traceable
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Users sacrifice privacy for functionality
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Centralized bridges can censor or freeze funds
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No way to use private assets in DeFi
Our Solution:
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Privacy-preserving bridge with zero-knowledge proofs
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Multi-party computation ensures no single point of failure
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Cryptographic proofs replace trust in intermediaries
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Censorship-resistant infrastructure
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Private assets can participate in DeFi
Real-World Impact
For Individuals:
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Protect your financial privacy from surveillance
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Move assets across chains without revealing amounts
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Use private assets in DeFi applications
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Maintain financial sovereignty
For Businesses:
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Protect competitive information (trading strategies, positions)
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Comply with regulations while maintaining privacy
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Enable private treasury management
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Support privacy-focused business models
For Society:
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Enable financial services in censored regions
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Protect vulnerable populations from financial surveillance
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Support privacy as a human right
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Build infrastructure for a free financial internet
The Future of Private Finance
FLASH Bridge is more than a bridge—it’s infrastructure for a new financial system where:
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Privacy is the default, not an option
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Freedom is built-in, not granted
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Security is mathematical, not assumed
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Users are sovereign, not subjects
We’re building the tools that will enable the next generation of private financial applications, where users can transact, lend, borrow, and trade without sacrificing their privacy or freedom.