zkVerify

Trustless blockchain verification over x402 with Merkle proofs + ECDSA signing

Why?

When an AI agent pays for blockchain data via x402, how does it know the data is authentic? It doesn't. 99% of x402 transactions are at risk (arXiv, July 2026 — 31 vulnerabilities found).

zkVerify solves this: every API response includes a Merkle proof + ECDSA signature. The agent can verify independently — zero trust required.

Endpoints

| Endpoint | Price | Returns | |----------|-------|---------| | GET /verify/balance/:address?chain=base | $0.02 | Account balance + Merkle proof + signature | | GET /verify/contract/:address?chain=base | $0.02 | Contract code hash + signature | | GET /health | Free | Service status + signer address | | GET /.well-known/x402 | Free | x402 discovery (Bazaar) |

Supported Chains

• Base (L2 — fallback to eth_getBalance)
• Ethereum (L1 — full eth_getProof / EIP-1186)
• Polygon

How It Works

1. Agent sends GET /verify/balance/0xABC...?chain=ethereum
2. zkVerify returns HTTP 402 Payment Required
3. Agent pays $0.02 USDC on Base via x402
4. zkVerify: a. Fetches eth_getProof from RPC b. Verifies Merkle Patricia Proof against stateRoot c. Signs the result with ECDSA d. Returns: { balance, blockNumber, stateRoot, merkleProof, signature }
5. Agent verifies: a. Signature (recoverAddress) b. Merkle proof locally (optional) c. stateRoot against block header (optional)
6. Agent now has 100% verified on-chain data — no trust needed

Quick Start

For AI Agents (via x402)

curl https://zkverify-production.up.railway.app/verify/balance/0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045?chain=ethereum
# Returns: balance, Merkle proof (9 nodes), ECDSA signature, verified: true

SDK (Client-side verification)

import { fullVerify } from "zkverify";

const result = await fetch("https://zkverify-production.up.railway.app/verify/balance/0xABC...?chain=ethereum").then(r => r.json());
console.log(result.fullyVerified); // true = verified 100%

MCP Server

zkVerify includes an MCP server with 3 tools for Claude/Cursor:

{
  "mcpServers": {
    "zkverify": {
      "command": "npx",
      "args": ["-y", "zkverify-mcp"],
      "env": {
        "ZKVERIFY_URL": "https://zkverify-production.up.railway.app"
      }
    }
  }
}

Architecture

• Merkle Patricia Proof: EIP-1186 eth_getProof from Ethereum L1
• ECDSA Signing: Every response signed with secp256k1
• x402 Payment: $0.02 USDC on Base
• Zero Trust: Agent needs no trusted oracle — just math

Costs

• $0 startup cost
• Free RPC (PublicNode, Alchemy free tier)
• x402 facilitator: free for first 1,000 transactions/day
• Margin: 99% (after $0.001 facilitator fee)

Patent (Pending)

Title: "System and method for providing cryptographically verifiable API responses using Merkle proofs and ECDSA signatures over HTTP payment protocols"

See patent/USPTO_PROVISIONAL.md

ZK Circuit (Level 2)

A simplified circom circuit (~202 constraints) proves that verification was performed correctly without revealing proof data.

See circuits/zkverify.circom

License

MIT — free to use, modify, and distribute. Attribution appreciated.

Links

• Live: https://zkverify-production.up.railway.app
• GitHub: https://github.com/zkarchitect/zkverify
• Health: https://zkverify-production.up.railway.app/health
• Discovery: https://zkverify-production.up.railway.app/.well-known/x402

Built with ZKForge — the first x402 service providing cryptographically verifiable blockchain data.