Suhyeon Lee

I’m a PhD researcher focused on the security of Blockchain and Cryptocurrency. Before academia, I spent 7 years in the military and finished as an army captain, which gave me some disciplined and hands-on experience. Now, I’m working on blockchain security at Tokamak Network, dealing with Layer 2 scalability and security issues. I also travel the world (mostly in Europe), and that really adds some fresh perspectives to my life. Outside of tech, I enjoy conversations about history, philosophy, jazz and science.

Current projects working on:

Layer 2 security and cost analysis
On-chain distributed randomness

latest posts

Mar 18, 2025	Centralization in Joseon and Decentralization in Japan
May 25, 2024	My First Car with an Engine Power Once Defeated a Mighty Dynasty
Apr 18, 2024	Prague in Spring - at the Previous Heart of European Politics

selected publications

2025

Looking for Attention: Randomized Attention Test Design for Validator Monitoring in Optimistic Rollups

Suhyeon Lee

In arXiv preprint arXiv:2505.24393, Jun 2025

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Optimistic Rollups (ORUs) significantly enhance blockchain scalability but inherently suffer from the verifier’s dilemma, particularly concerning validator attentiveness. Current systems lack mechanisms to proactively ensure validators are diligently monitoring L2 state transitions, creating a vulnerability where fraudulent states could be finalized. This paper introduces the Randomized Attention Test (RAT), a novel L1-based protocol designed to probabilistically challenge validators in ORUs, thereby verifying their liveness and computational readiness. Our game-theoretic analysis demonstrates that an Ideal Security Equilibrium, where all validators are attentive and proposers are honest, can be achieved with RAT. Notably, this equilibrium is attainable and stable with relatively low economic penalties (e.g., under $1000) for non-responsive validators and a low attention test frequency (e.g., under 1% per epoch). RAT thus provides a crucial, practical mechanism to enforce validator diligence, fortifying the overall security and integrity of ORU systems with minimizing additional costs.