ZK ID — Anonymous Named Accounts on Nara Chain

ZK ID is now live on Nara Chain — a protocol that lets you register human-readable names (like "alice") as private, reusable receiving addresses. Anyone can deposit NARA knowing only the name, and only the owner can withdraw anonymously. No on-chain link between the ZK ID and the withdrawal address is ever created.

How It Works

ZK ID combines Groth16 zero-knowledge proofs with a 64-level Merkle tree to achieve full sender-receiver unlinkability:

1. Register — Derive a cryptographic secret (idSecret) from your wallet, compute a commitment, and register the ZK ID on-chain. Your wallet address never appears in the registration transaction
2. Deposit — Anyone who knows the name can deposit NARA. Fixed denominations (1 / 10 / 100 / 1,000 / 10,000 / 100,000 NARA) prevent amount-based correlation
3. Withdraw — Generate a Groth16 proof off-chain and send it to any recipient address. The proof convinces the on-chain program that you know the secret — without revealing it
4. Transfer — Hand over ownership to a new identity via ZK proof, without exposing any wallet address

Privacy Guarantees

Operation	Visible On-Chain	Hidden
Register	Payer address, name hash, commitment	Owner's wallet, plaintext name
Deposit	Depositor address, name hash, amount	Owner's wallet, plaintext name
Withdraw	Payer address, recipient, nullifier	ZK ID identity, secret
Transfer	Payer address, name hash, new commitment	Owner's wallet, secret

The protocol supports delegated registration — a relayer can submit the registration transaction so the owner's wallet never appears on-chain at all.

Quick Start

# Register a ZK ID
npx naracli zkid create alice

# Deposit 10 NARA (anyone can do this knowing the name)
npx naracli zkid deposit alice 10

# Scan for claimable deposits
npx naracli zkid scan alice

# Withdraw anonymously
npx naracli zkid withdraw alice

For Developers

The nara-sdk provides full programmatic access:

import {
  deriveIdSecret, createZkId, deposit,
  scanClaimableDeposits, withdraw,
  generateValidRecipient, ZKID_DENOMINATIONS,
} from 'nara-sdk';

const idSecret = await deriveIdSecret(wallet, 'alice');
await createZkId(connection, wallet, 'alice', idSecret);
await deposit(connection, wallet, 'alice', ZKID_DENOMINATIONS.SOL_1);

const deposits = await scanClaimableDeposits(connection, 'alice', idSecret);
const recipient = generateValidRecipient();
await withdraw(connection, wallet, 'alice', idSecret, deposits[0]!, recipient.publicKey);

Cryptographic Design

• Proof system: Groth16 on BN254 elliptic curve
• Hash function: Poseidon (ZK-circuit-friendly, on-chain via solana-poseidon syscall)
• Merkle tree: 64 levels, supports 2^64 leaves, 30-root history buffer
• idSecret derivation: Ed25519_sign → SHA-256 → mod BN254_PRIME (deterministic, no extra storage needed)
• Double-spend prevention: Nullifier PDAs — each deposit can be withdrawn exactly once

Key Details

Item	Value
Program Address	ZKidentity111111111111111111111111111111111
Denominations	1 / 10 / 100 / 1,000 / 10,000 / 100,000 NARA
Merkle Depth	64 levels
Root History	30 most recent roots

Learn More

• ZK ID SDK — Full API reference
• CLI Reference — All zkid commands