🛡️ ZKP-Based NFT (Zero-Input Solidity Contract)

A minimal Zero-Knowledge Proof (ZKP) verified NFT smart contract built entirely in Solidity, featuring:

🚫 No imports
🚫 No constructors
🚫 No declared input parameters
🧠 ZKP-style verification flow using raw calldata
🎨 ERC-721-like NFT minting for verified users

🔗 Deployed By

Author: Punya Jain
Ethereum Address: 0x818df1B6517D88D52Ff66bD5d1628E486b66dff7

📘 Overview

This project demonstrates how verified users can mint NFTs using a Zero-Knowledge Proof mechanism — without needing to import external libraries or define input parameters.

The contract uses raw msg.data for proof verification and metadata initialization, achieving a pure and minimalist Solidity design.

✨ Key Features

Fully self-contained — no external dependencies or imports.
Admin initialization via initAdmin().
ZKP verification (via verifyProof) uses user-provided calldata.
Mint verified NFTs directly using mintVerified().
Minimal ERC-721 implementation (transfer, approve, balance, ownerOf).

⚙️ Contract Functions

Function	Description	Inputs	Notes
`initAdmin()`	Initializes the deployer/admin (can only be called once)	None	Sets `owner = msg.sender`
`setVerifierRoot()`	Sets the verifier root/commitment	32 bytes in calldata	No input parameters declared; calldata is read directly
`mintVerified()`	Mints a verified NFT if proof passes	Proof bytes in calldata	Verifies proof using `keccak256(user, proof)` vs stored root
`transferFrom()`	Standard ERC721 transfer	-	Simplified transfer function
`burn()`	Burns a token	-	Owner or approved operator only

🔍 ZKP Verification Logic (Demo)

This is a placeholder verifier:

bytes32 h = keccak256(abi.encodePacked(user, proof));
return (h == verifierRoot);

✅ Replace verifyProof() with an actual zkSNARK/zk-STARK verifier generated from your zero-knowledge circuit for production-grade verification.

🚀 Usage

1️⃣ Deploy

Deploy the contract normally using Remix, Hardhat, or Foundry.

2️⃣ Initialize Admin

Call:

initAdmin()

(First caller becomes admin.)

3️⃣ Set Verifier Root

To set the verification root (example root = 0xabc...):

calldata = selector(setVerifierRoot) || abi.encode(root)

Example in ethers.js:

const iface = new ethers.utils.Interface(["function setVerifierRoot()"]);
const selector = iface.getSighash("setVerifierRoot()");
const root = "0xabc..."; // 32-byte commitment
const data = selector + root.slice(2);
await signer.sendTransaction({ to: contract.address, data });

4️⃣ Mint Verified NFT

Call mintVerified() with proof bytes appended to calldata:

const iface = new ethers.utils.Interface(["function mintVerified()"]);
const selector = iface.getSighash("mintVerified()");
const proof = "0x1234abcd..."; // arbitrary proof bytes
const data = selector + proof.slice(2);
await signer.sendTransaction({ to: contract.address, data });

If keccak256(abi.encodePacked(user, proof)) == verifierRoot, mint succeeds 🎉

🧩 Technical Stack

Language: Solidity ^0.8.20
Standard: ERC-721 (simplified)
Verification: Placeholder hash-based ZKP
Storage: Minimal mappings for balances and ownership

📜 License

💬 Contact

📧 Email: [add your email if you want] 🐦 Twitter: @PunyaJain1608 🔗 Ethereum: 0x818df1B6517D88D52Ff66bD5d1628E486b66dff7

⭐ If you found this project interesting, give it a star on GitHub!

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