A searchable publication list with local PDFs where possible.

Brief Announcement: Delay-Optimal Transaction Order Fairness

Zhuo Cai^αA. Goharshady^αα Alphabetical order

ACM Symposium on Principles of Distributed Computing · 2026

Transaction order fairness is emerging as a critical defense against Miner Extractable Value (MEV) and censorship, problems that traditional consensus protocols exacerbate by seeking only standard consistency and liveness. This work stands among the few to rigorously address these issues through a strong, fine-grained fairness definition. Unlike existing schemes that settle for (1) coarse "block-order fairness," which still permits intra-block manipulation, or (2) "bounded unfairness," which suffers from high computational overhead, or (3) median timestamp ordering, which is susceptible to manipulation, we propose an alternative driven by Delay-Optimality. We revisit Approximate-Order-Fairness (AOF), which mandates that if a fraction φ of nodes receive transaction tx at least time δ before tx', then tx must be ordered before tx'. While previously dismissed in the literature due to impossibility reductions by a reduction to the ideal but impossible receive-order-fairness, we observe that the reduction relies on an overly restrictive assumption of logical-round-based clock functionality. In practice, especially for modern blockchain applications, we can adopt global physical time to circumvent the reduction. We identify a robust Feasible Region where Condorcet cycles are provably impossible: in a permissioned system of n nodes of which f are Byzantine, under a fully synchronous network of delay Δ, for any k ∈ ℤ⁺, (φ,δ)-AOF is feasible for any φ > 1 − (n−f)/(nk) and δ > Δ/k. We design protocols to achieve AOF that do not rely on a fixed delay parameter δ. Instead, they dynamically compute the optimal δ for each block based on the observed transaction profile, ensuring the strongest possible fairness guarantee under current network conditions. This feature also makes it robust against some asynchrony. We also provide a comprehensive comparison of AOF with existing definitions, demonstrating that AOF offers a compelling fairness alternative while maintaining practical efficiency.

Extending Programmable Blockchain Protocols to Enable and Incentivize Parallel Execution of Smart Contracts

T. Barakbayeva^αX. Cai^αZhuo Cai^αA. K. Goharshady^αα Alphabetical order

The 7th International Conference on Mathematical Research for Blockchain Economy · 2026

Rogue: Updatable Matrix Lookup Arguments and Applications to Verifiable Databases

C. PappasZhuo CaiD. Papadopoulos

ACM SIGSAC Conference on Computer and Communications Security · 2026

To appear.

Rogue develops updatable matrix lookup arguments and studies how they can be used to support verifiable database applications, with an emphasis on proof-system expressiveness and efficient update handling.

LockFee: Refundable Transaction Admission via Time-Locked Collateral

J. Ballweg^αT. Barakbayeva^αZhuo Cai^αA. Goharshady^αα Alphabetical order

IEEE International Conference on Decentralized Applications and Infrastructures · 2026

Alphabetical author order with Amir Goharshady.

We present LockFee, a principal-preserving admission primitive in which each accepted transaction locks collateral for a fixed duration and recovers the principal in full afterward; users bear only the opportunity cost of locked capital.

Proof of Election: A Formally-Verified Democratic Blockchain Protocol

Zhuo Cai^αA. Goharshady^αα Alphabetical order

IEEE International Conference on Decentralized Applications and Infrastructures · 2026

Alphabetical author order with Amir Goharshady.

We present Proof-of-Election, a new blockchain consensus protocol that mimics real-world democratic elections, to vote based on block contents rather than blindly trust proposers, and only admit the highest voted block in each slot.

Smart Contracts for Trustless Sampling of Correlated Equilibria

T. Barakbayeva^αZhuo Cai^αA. Goharshady^αK. Keypoor^αα Alphabetical order

International Joint Conference on Artificial Intelligence · 2025

Alphabetical author order with Amir Goharshady.

This paper gives two trustless smart-contract protocols for sampling correlated equilibria on blockchain, replacing the traditional trusted mediator with cryptographic techniques based on oblivious transfer and zkSNARKs.

Strategic Mining in Proof-of-Stake with Practical Random Election

Zhuo Cai

IACR Cryptology ePrint Archive · 2025

IACR ePrint 2025/1428.

This manuscript studies strategic mining in proof-of-stake systems when random beacon output is fixed across multiple future slots within an epoch. It formalizes the lookahead effect created by practical random election and gives an efficient optimal attack algorithm showing profitable deviations at much lower stake fractions than earlier per-slot-randomness models.

Gas-Efficient Decentralized Random Beacons

V. Abidha^αT. Barakbayeva^αZhuo Cai^αA. Goharshady^αα Alphabetical order

IEEE International Conference on Blockchain and Cryptocurrency · 2024

Alphabetical author order with Amir Goharshady.

This paper develops decentralized random beacon protocols with explicit attention to gas efficiency, aiming to keep randomness services practical for on-chain use without weakening decentralization goals.

SRNG: An Efficient Decentralized Approach for Secret Random Number Generation

T. Barakbayeva^αZhuo Cai^αA. Goharshady^αα Alphabetical order

IEEE International Conference on Blockchain and Cryptocurrency · 2024

Alphabetical author order with Amir Goharshady.

SRNG presents an efficient decentralized approach to secret random number generation, aiming to provide tamper-resistant randomness while preserving the privacy properties needed by higher-level blockchain protocols.

Asparagus: Automated Synthesis of Parametric Gas Upper-Bounds for Smart Contracts

Zhuo Cai^αS. Farokhnia^αA. Goharshady^αS. Hitarth^αα Alphabetical order

ACM SIGPLAN Conference on Object-Oriented Programming, Systems, Languages, and Applications · 2023

Alphabetical author order with Amir Goharshady.

This paper presents Asparagus, an automated tool for synthesizing parametric static gas upper bounds for smart contracts. The main technical contribution is to employ sound quantifier elimination techniques based on Farkas' lemma and other algebro-geometric methods.

Trustless and Bias-Resistant Game-Theoretic Distributed Randomness

Zhuo Cai^αA. Goharshady^αα Alphabetical order

IEEE International Conference on Blockchain and Cryptocurrency · 2023

Alphabetical author order with Amir Goharshady.

In randomness generation smart contracts, participants are assumed but have no incentive to submit random integers rather than sending arbitrary values. This paper presents a novel matrix game to enforce uniformity of batched value generation by collision-resistant Nash equilibria.

Game-Theoretic Randomness for Proof-of-Stake

Zhuo Cai^αA. Goharshady^αα Alphabetical order

The 4th International Conference on Mathematical Research for Blockchain Economy · 2023

Alphabetical author order with Amir Goharshady.

PoS requires decentralized randomness. Existing randomness generation protocols either rely on pseudo-randomness, or assume that a majority of the participants are honest in submitting their randdomness share and follow the rest of the protocol. However, these participants have no incentive to contribute true random shares compared to contributing an arbitrary share in the first place. This paper presents a game-theoretic design for incentivizing participants submitting true random shares, without relying on pseudo-randomness.

PureLottery: Fair Leader Election Without Decentralized Random Number Generation

J. Ballweg^αZhuo Cai^αA. Goharshady^αα Alphabetical order

IEEE International Conference on Blockchain · 2023

Alphabetical author order with Amir Goharshady.

PureLottery studies fair leader election without relying on a decentralized random number generation service, but instead leveraging a tournament among interested participants.

Towards Visual Question Answering on Pathology Images

X. He^*Zhuo Cai^*W. WeiY. ZhangL. MouE. XingP. Xie^* Equal contribution

Annual Meeting of the Association for Computational Linguistics · 2021

* Equal contribution.

This paper studies visual question answering over pathology images and explores how multimodal models can answer medically grounded questions in a scientific imaging domain rather than a natural-image setting.