Writing
Notes on research, teaching, and things I’ve helped build.
- Nubit releases Thunderbolt for Bitcoin transfers to offline recipients
The design kept changing. Eventually, Thunderbolt became a CCS paper and an open-source project.
Building - Reversing three cards illustrates how recursive programs work
Before explaining the code, try reversing a row of cards.
Teaching - Nubit demonstrates Thunderbolt payments with BRC-20 creator Domo
From verifying token balances to transferring bitcoin: research questions behind a Bitcoin 2025 demonstration.
Building - Fried Rice DAO brings more than 500 people together in Las Vegas
My friend Chaofan’s invitation to share a meal became a gathering much larger than we had imagined.
Notes - Bitcoin TVL figures need evidence that the coins are locked
Proof of TVL, proofs of solvency, and the different claims hidden inside a single Bitcoin balance.
Research - Tornado Crash shows how one deposit can be withdrawn twice
A BlazCTF challenge where a valid proof could still let the same deposit pay out twice.
Research - A division bug shows why cryptographic proofs need complete arithmetic rules
A repair to a cryptography library illustrates why verifying division requires care with both the answer and the way numbers are written.
Research