zkCoins
zkCoins is a wallet for Shielded CSV — a protocol that brings true privacy to Bitcoin through Client-Side Validation and Zero-Knowledge Proofs. No soft fork required. No new consensus rules. Bitcoin as it exists today.
What can users do?
| Action | Description |
|---|---|
| Create Wallet | Generate a BIP32 HD wallet locally. Keys never leave the browser. |
| Receive | Share your address. Incoming coins appear automatically. |
| Send | Send coins to any zkCoins address. Only sender and receiver see the details. |
| Faucet | Mint testnet coins for testing (testnet only). |
How it works
When you send zkCoins, the protocol generates a Zero-Knowledge proof that the transaction is valid — without revealing amounts, sender, receiver, or transaction history. Only a 64-byte nullifier is written to the Bitcoin blockchain, an opaque blob that prevents double-spending. Nothing more.
Normal Bitcoin TX: ~560 weight units — sender, receiver, amount, all visible
zkCoins TX: ~64 weight units — one nullifier, completely opaque
The blockchain serves one purpose: proving that each coin is spent only once. Everything else — validation, balances, history — happens client-side between sender and receiver.
Key properties
- Private by default: amounts, sender, receiver, and transaction graph are hidden
- No protocol changes: works on Bitcoin as it exists today, no soft fork
- ~100 TPS: 8.75x more efficient than regular Bitcoin transactions
- Constant proof size: verification cost is independent of transaction history
- No coordinator: peer-to-peer, no central service to shut down
- Self-custodial: keys are generated and stored locally in the browser
Protocol
zkCoins implements the Shielded CSV protocol by Jonas Nick (Blockstream), Liam Eagen (Alpen Labs), and Robin Linus (ZeroSync). This wallet builds on the ZeroSync prototype.