Blockchain Protocol Engineer — payments & settlement · smart contracts · zero-knowledge · L2
Six years shipping production protocols end-to-end at Tokamak Network (Ethereum L2): token-economy contracts, a live staking protocol maintained through external audits, zkVM applications, and privacy-preserving settlement systems. Now building open-source infrastructure for stablecoin payments.
📍 Seoul · UTC+9 · open to remote protocol / smart-contract roles
| What | Status | |
|---|---|---|
| token-kit | Modular ERC-20 issuance kit following Circle's FiatToken: byte-identical EIP-3009 type hashes (x402 clients work unchanged), timelock + Guardian veto on issuance authority and upgrades | Apache-2.0 · 103 Foundry tests incl. symbolic (Halmos) |
| x402-kit | x402 payments for HTTP APIs: one-line seller middleware, capped buyer fetch wrapper, self-hostable facilitator. Any EIP-3009 token directly, any ERC-20 via Permit2; EOA / ERC-1271 / ERC-6492 signers; open-amount (upto) payments |
Apache-2.0 · TypeScript · 203 unit tests + on-chain e2e · on npm as @x402.kit/* |
Design notes I care about in this work: issuance authority that can be vetoed, spending caps enforced by construction on the payer side, spec-exact wire compatibility, and tests that pin EIP-712 digests to golden vectors so a refactor can't silently change what users sign.
| Project | What it is |
|---|---|
| zkScatter | Privacy-preserving settlement protocol — private OTC trading and bulk payouts on one ZK stack: Groth16 commitment pools, gasless relayed claims, compliant identity gating |
| zk-X509 | On-chain identity from existing X.509 certificates (Korean NPKI, eID, corporate CAs) via SP1 zkVM — only nullifiers on-chain, private keys never enter the zkVM. MIT · live on Sepolia → zk-x509.web.app |
| zk-card-wallet 🔒 | X.509-authenticated hardware wallet: JavaCard applet (secure channel, dual secp256k1 / BabyJubJub signing) + circom proving pipeline + mobile app |
| ethrex | SP1 zkVM proving integrated into a Rust L2 client — bridge guest program, proving profiling baseline |
- TON Staking V2 — live seigniorage & staking protocol; founded the repo, top contributor, maintained three years through external audits
- TONStarter — IDO launchpad in production (2021–22): sale / staking / reward contracts, vesting vault factory
- Rollup metadata registry + checker — L2 registration standard used across the ecosystem
- DAO governance stack — original DAO contracts / backend (2020) and the 2025 community rebuild
- ChainForge Studio — modular app-chain (rollup) factory on ethrex: web wizard → deployable rollup spec + L1 contract deployment
- Tokamon Go — location-based TON reward service: contracts + web + iOS + listener · live at tokamon.io
- Full Uniswap V3 stack fork and integration on an optimistic rollup (contracts, smart order router, interface, analytics)
- AI-agent development pipeline, verification first. I design the decomposition, specs, and acceptance checks; coding agents implement; every PR passes layered AI reviewers (Claude · Copilot · CodeRabbit · Sonar) with mandatory feedback-resolution commits before merge. Tool claims get re-measured, not trusted.
- Throughput this enables: ~5,600 commits / 1,000+ merged PRs in H1 2026 as a single engineer, across the repos above. Lifetime in one ecosystem: 9,000+ commits, 1,748 merged PRs (94.6% merge rate).
- Verification stack: Foundry + Halmos symbolic tests, EIP-712 golden vectors, Slither in CI, on-chain e2e harnesses.
Solidity Foundry / Halmos TypeScript Rust Java (JavaCard) SP1 zkVM Groth16 / circom
EIP-712 · EIP-3009 · Permit2 · ERC-1271 / 6492 Uniswap V3/V4 OP-stack Node.js Docker GCP / AWS
- Lecturer, Korea University — smart contract development (blockchain course)
- 🔒 = private repository; contribution metrics verifiable on request