🔐 Proof160 Identity Sandbox

A guided journey to create verifiable proof of Bitcoin ownership for EVM chains.

🔸 This sandbox never connects to a blockchain
🔸 All data stays in your browser
🔸 No private keys or signatures leave your device
🔸 This is for education only
🎓 Classroom Mode

Learn How It Works

Understand the cryptographic link between Bitcoin and EVM chains in a safe, risk-free environment.

🎓 Learning Objective: See how an EVM address is transformed into a Bitcoin signature, and how that signature identifies your unique Hash160 identifier. No real keys are required here.
Note: We automatically convert to lowercase for cryptographic consistency. Try using 0x1234...abcd for a demo.

🏫 Classroom FAQ

❓ How is this sandbox different from the real FastPath?
In the sandbox, we generate a throwaway Bitcoin keypair in your browser, sign your EVM address, and show the derived Hash160 immediately. Nothing touches a real blockchain. In production on Sepolia, you will:
  • Sign with your real Bitcoin wallet (Ledger, Electrum, Sparrow)
  • Send the proof to the Proof160 contract to anchor it on-chain
  • Reuse the same Hash160 across any SegWit/Taproot/Legacy format
Hash160 is the bridge—20 bytes that smart contracts can verify without moving BTC.
⛓️ Why is Proof160 on Sepolia?
Sepolia provides the perfect balance for Bitcoin-EVM linking:
  • 💰 Low Cost: Linking your identity costs ~$0.10 vs ~$50 on Ethereum mainnet.
  • 🔒 Maximum Security: Your proof inherits Ethereum's security via Sepolia's testnet environment.
  • 🔄 EVM Ecosystem Access: Once linked, you can use your Bitcoin proof across Sepolia DeFi (Aave, GMX, Camelot), NFTs, and social apps.
  • 🌐 Future-Proof: Your Hash160 works on all EVM chains. Start on Sepolia, use anywhere.
Hash160 is chain-agnostic - it's just 20 bytes of data. Sepolia's EVM compatibility means the same contract code works on Arbitrum, Ethereum, Polygon, etc., and lower gas on Sepolia enables more features.
How does the cryptography work?
We use the standard Bitcoin "Sign Message" protocol. You sign your EVM address with your Bitcoin key. The resulting signature allows anyone to mathematically resolve your Public Key and verify you own the Bitcoin address.
What is Hash160?
It's a 20-byte fingerprint of your Public Key. It's the "DNA" of your Bitcoin identity that stays the same whether you use Legacy, SegWit, or Taproot addresses.
Why is this safe?
In this classroom mode, we use random keys. In production, you sign in an air-gapped environment using a cold wallet (like Ledger or Trezor) or a secure software wallet like Electrum. Your private key never leaves your device and is never exposed to the internet.
🔬 Test Mode

Verification Lab

Already have a signature? Test it here to ensure everything is correct before committing to the blockchain.

🔬 Lab Objective: Verify that your real Bitcoin signature correctly identifies your Public Key and matches your EVM address. This is a test—nothing is stored on-chain yet.
In this sandbox, we automatically simulate a valid Bitcoin signature for you.

🔬 Lab FAQ

⚠️ Address Mismatch Warning
Always make sure your public key matches the Bitcoin address expected. If it automatically shows a different one, manually override.

If addresses don't match:
  • You may be using a different derivation path
  • You may have signed with the wrong wallet
  • Do NOT proceed until resolved
Common reasons for mismatch:
  1. Signed with wrong Bitcoin wallet
  2. Used wrong derivation path
  3. Wallet showed different address than expected. To avoid that, double check (for example on "Electrum", right click on the address, look for the tab where it shows the "Public Key"). It's simple, and will avoid this rare but known issue.
My signature failed—what went wrong?
Common issues: 1) The message signed must be the exact lowercase EVM address (including 0x). 2) Ensure you are using a standard Bitcoin wallet. We highly recommend Electrum for its robust "Sign Message" feature.
Does capitalization matter?
Yes! FastPath expects the lowercase version of your EVM address to ensure consistency across all platforms. Our UI handles this conversion for you automatically.
How do I sign a message with Ledger?
For maximum security, connect your Ledger to Electrum. This allows you to sign the message in an air-gapped fashion where the private key never touches an internet-connected machine.
🏗️ Simulation Mode

Finalize Your Identity

Create a permanent, verifiable link between your Bitcoin and EVM identities in this simulation.

🏗️ Finalization Objective: Connect your wallet and simulate your proof. Once finalized, smart contracts in production can "see" your Bitcoin ownership, unlocking DeFi and governance rights.

🏗️ Finalization FAQ

What happens in production?
In the real protocol, your EVM address and your Bitcoin Hash160 are mapped together in the FastPath smart contract without exposing your private keys. This creates:
  • Permanent History: Lenders can see your consistent Bitcoin ownership over time, and DAOs can verify long-term holder status for governance.
  • Anti-Sybil Protection: It eliminates "Double-Spend" identity attacks by ensuring you can't link the same Bitcoin to multiple EVM addresses simultaneously to game systems.
🔄 Can I change my linked EVM address later?
No. Each Bitcoin identity (Hash160) can only be linked to one EVM address, and each EVM address can only receive one Bitcoin identity link. This exclusivity ensures the cryptographic proof cannot be duplicated or manipulated. If you need to use a different EVM address, you must start with a new Bitcoin wallet.
🔐 What happens if I lose access to my EVM wallet?
Your Bitcoin remains secure in cold storage, but you lose the ability to use the linked capabilities (DeFi, governance, etc.). You cannot transfer the link to a new EVM address. This is why securing your EVM wallet is critical after creating the link.

🛡️ Why This 1:1 Binding is Actually Better

While restrictive, this design has significant advantages for your security and the integrity of the network:

  • ✓
    Prevents Sybil Attacks
    Ensures bad actors can't game systems by creating multiple fake identities from the same Bitcoin stack.
  • ✓
    Simplifies Verification
    One Bitcoin → One EVM. No ambiguity, no confusion for smart contracts or lenders.
  • ✓
    Creates True Digital Identity
    Mimics real-world "one person, one identity" principles, making your link more valuable for high-trust applications.
  • ✓
    Eliminates Confusion
    No wondering "which link is active?". This permanence is the bedrock of cryptographic security.
🖼️ NFT Preview

Exclusive Bitcoin NFTs

Mint the demo Early Adopter NFT in its own space—no DeFi widgets or vault controls mixed in.

🎖️ Focused experience: This panel is only for the NFT demo. It uses the same wallet connection as the rest of the sandbox but keeps the UI separate from the lending controls.
Connect wallet to mint
🎖️ Early Adopter NFT (demo)
Mint a Bitcoin OG badge on EVM. This is a simulation and stays separate from the BTC-backed DeFi flows.
Ready to mint (demo)
⚖️ Bitcoin DAO

Governance Demo

Vote on proposals with your real Bitcoin holdings. 1 satoshi = 1 vote. No wrapped tokens.

🏛️ How Bitcoin Governance Works: Your voting power equals your actual Bitcoin balance (in satoshis). This creates true stake-weighted governance where long-term holders have the most say—no token farming, no dilution.
Connect wallet to participate
📜 Deployed Contracts (Sepolia)
BitcoinDAO: 0x8f92abBB1081879a9aCC5E30E28611047a7e7CA2
FastPathIdentity: 0x2bAeD4982Aa37c9b7ab5Cd321f4f29e59D9C8757

⚖️ Governance FAQ

Why use real Bitcoin for voting?
Traditional DAOs use mintable governance tokens that can be farmed or bought. Bitcoin DAO ties voting power to actual BTC holdings—no inflation, no Sybil attacks. Long-term Bitcoin holders naturally have the most influence.
Is my Bitcoin at risk?
No. Your Bitcoin stays in cold storage. You only prove ownership via your Hash160 identity. The DAO reads your balance from an oracle—your BTC never moves.
How is voting power calculated?
1 satoshi = 1 vote. If you hold 1.5 BTC, you have 150,000,000 votes. This creates proportional representation based on real economic stake.
🏦 DeFi Showcase

BTC-Backed Lending Demo

Experience how your Bitcoin identity unlocks real financial utility on EVM chains.

LIVE
ETH Collateral
LIVE
dUSD Borrowed
LIVE
Active Users
50%
Max LTV
Fixed Rate
💰 Prices (live): ETH: … BTC: … (Demo math in contract still uses $2,000/ETH for limits)
🌟
Live Demo Identity
Registered on Sepolia • Ready to use
EVM Address
0x6227e26f3b705e9e0d395cb9cf501a0190ec0510
Bitcoin Address
bc1qcutq0sh45e6t27avhfkarcqtvpa9jc24fptask
Hash160 Identity
0xc71607c2f5a674b57bacba6dd1e00b607a596155
🔍 View on Etherscan →

⚡ How BTC-Backed Lending Works

1
Register Identity
Link your Bitcoin to EVM via signature
2
Deposit ETH
Add collateral to the vault
3
Borrow dUSD
Mint stablecoins (50% LTV)
4
Repay & Withdraw
Get your collateral back
👛 Connect your wallet to interact with the vault

🏦 Lending FAQ

Why do I need a Bitcoin identity to borrow?
Traditional DeFi is anonymous. By linking your Bitcoin identity, you prove you are a long-term stakeholder in the ecosystem. This allows protocols to offer better rates, higher LTVs, or exclusive access to "Bitcoin-only" liquidity pools.
Is my Bitcoin at risk?
No. Your Bitcoin stays in your cold storage. You are only using the proof of ownership to unlock utility on the EVM chain. The collateral you deposit here is ETH, but the right to borrow is granted by your Bitcoin identity.
What is dUSD?
dUSD (Demo USD) is a test stablecoin minted by the BTCBackedVault. It demonstrates how real protocols could mint synthetic dollars against verified Bitcoin identity. 1 ETH = $2000 in this demo.
📜 Deployed Contracts (Sepolia)
BTCBackedVault: 0xE62feC78242b28dB89c80dBbf46576DBAd46D35E
DemoUSD Token: 0xc87D98735fc7300A4e708841a6074A2F30495b06
FastPathIdentity: 0x2bAeD4982Aa37c9b7ab5Cd321f4f29e59D9C8757
₿ → ✨ Send BTC via Solana

Send Bitcoin Without a Bitcoin Wallet

Connect Phantom → Sign once → Get instant proof + BTC broadcast.

⚡ How it works:
1. Your Hash160 identity links your wallets (EVM ↔ Solana ↔ BTC)
2. Sign in Phantom = instant Solana proof (400ms)
3. Relayer broadcasts real BTC = settlement (10-60 min)
Result: Two independent proofs on two chains.
1
Connect Phantom Wallet
Activity Log
Ready. Connect Phantom to start.

📖 How This Works

Why is this better than just sending BTC directly?
Instant Proof: Solana confirms in 400ms. You can show the recipient "I sent it" immediately.
No BTC Wallet Needed: Control your BTC with just Phantom.
Dual Receipts: Immutable proof on both Solana AND Bitcoin for disputes/accounting.
Where does the BTC come from?
From your Hash160-linked identity. You deposited BTC earlier (or it was credited to your identity). This system only releases BTC from addresses you control via Hash160 — never arbitrary addresses.

Proof160 Identity Sandbox

🔸 No blockchain connection 🔸 Local browser data only 🔸 No keys leave device 🔸 Educational use only