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Abstract — Electronic voting has been a hot research topic for decades and has recently garnered much attention due to the invention of programmable blockchains that support smart contracts. This is the ideal framework and technology for electronic voting since voting protocols implemented as smart contracts automatically inherit many desired properties from the underlying blockchain, e.g. verifiability, transparency and pseduonymity. However, the public and decentralized nature of the blockchain allows all transactions to be traced by everyone and thus voters’ choices would be disclosed publicly. There are many solutions to make blockchain-based voting fully anonymous and untraceable. A recent example is Tornado Vote [1] (ICBC 2023). Such protocols often rely on zero-knowledge proofs, especially zkSNARKS, to achieve secrecy and break the link between a voter’s public key and vote. However, verifying these proofs on-chain is expensive and uses a considerable amount of gas (execution fees).

Recommended citation: A. K. Goharshady and Z. Lin, "Blind Vote: Economical and Secret Blockchain-Based Voting," in 7th IEEE International Conference on Blockchain (Blockchain), 2024, pp. 46-53.
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Improved Gas Optimization of Smart Contracts

Published in FSEN, 2025

Abstract — Smart contracts are programs executed on top of a blockchain consensus protocol. Their compiled code (bytecode) is stored on the blockchain and is immutable after deployment. They are self-enforcing in the sense that any function call to a smart contract is executed by all nodes on the network, ensuring that they all reach consensus about the final state of the contract. To prevent denial-of-service attacks, such an execution is costly by design. A “gas” cost is assigned to each bytecode operation, roughly proportional to the resources required to execute it, and any user who initiates a function call to a smart contract has to pay the total gas cost of the resulting execution. On Ethereum alone, the users pay an astounding gas cost of more than 4 billion USD/year.

Recommended citation: T. Barakbayeva, S. Farokhnia, A. K. Goharshady, P. Li, Z. Lin, "Improved Gas Optimization of Smart Contracts," in 11th International Conference on Fundamentals of Software Engineering (FSEN), 2025, pp 1-10.
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Fast and Gas-efficient Private Sealed-bid Auctions

Published in PODC, 2025

Abstract — In decentralized blockchain environments, auctions must ensure fairness, trustless execution and bid confidentiality while operating efficiently within resource-constrained smart contracts. We propose a new family of algorithms for private, trustless auctions that protect bidder identities and bid values while remaining practical for smart contract execution. Our approach builds on top of the Dutch auction model and a stepwise revelation tree. Bidders commit to their bids using cryptographic commitment schemes and later confirm their honest following of the protocol through zero-knowledge proofs, ensuring that only the highest bid is disclosed while all other bids remain (probabilistically) confidential. A key innovation is the use of a reveal tree, which structures the bidding process into logarithmically many rounds, reducing the total number of messages to $O(\log n)$ and thereby significantly lowering gas costs and execution times. We further explore variants introducing fake bids to optimize our probabilistic privacy guarantees.

Recommended citation: J. Ballweg, A.K. Goharshady, Z. Lin, "Fast and Gas-efficient Private Sealed-bid Auctions," in 44th ACM Symposium on Principles of Distributed Computing (PODC), 2025, pp 169-172.
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MPhil Thesis - Novel Blockchain-based Protocols for Electronic Voting and Auctions

Published in Hong Kong University of Science and Technology, 2025

Abstract — Programmable blockchains have long been a hot research topic given their tremendous use in decentralized applications. Smart contracts, using blockchains as their underlying technology, inherit the desired properties such as verifiability, immutability, and transparency, which make it a great suit in trustless environments.

Download Paper

Blind Vote: Economical and Secret Blockchain-based Voting

发表于 IEEE Blockchain 2024

摘要 — Electronic voting has been a hot research topic for decades and has recently garnered much attention due to the invention of programmable blockchains that support smart contracts. This is the ideal framework and technology for electronic voting since voting protocols implemented as smart contracts automatically inherit many desired properties from the underlying blockchain, e.g. verifiability, transparency and pseduonymity. However, the public and decentralized nature of the blockchain allows all transactions to be traced by everyone and thus voters’ choices would be disclosed publicly. There are many solutions to make blockchain-based voting fully anonymous and untraceable. A recent example is Tornado Vote [1] (ICBC 2023). Such protocols often rely on zero-knowledge proofs, especially zkSNARKS, to achieve secrecy and break the link between a voter’s public key and vote. However, verifying these proofs on-chain is expensive and uses a considerable amount of gas (execution fees).

Recommended citation: A. K. Goharshady and Z. Lin, "Blind Vote: Economical and Secret Blockchain-Based Voting," in 7th IEEE International Conference on Blockchain (Blockchain), 2024, pp. 46-53.
Download Paper

Improved Gas Optimization of Smart Contracts

发表于 FSEN 2025

摘要 — Smart contracts are programs executed on top of a blockchain consensus protocol. Their compiled code (bytecode) is stored on the blockchain and is immutable after deployment. They are self-enforcing in the sense that any function call to a smart contract is executed by all nodes on the network, ensuring that they all reach consensus about the final state of the contract. To prevent denial-of-service attacks, such an execution is costly by design. A “gas” cost is assigned to each bytecode operation, roughly proportional to the resources required to execute it, and any user who initiates a function call to a smart contract has to pay the total gas cost of the resulting execution. On Ethereum alone, the users pay an astounding gas cost of more than 4 billion USD/year.

Recommended citation: T. Barakbayeva, S. Farokhnia, A. K. Goharshady, P. Li, Z. Lin, "Improved Gas Optimization of Smart Contracts," in 11th International Conference on Fundamentals of Software Engineering (FSEN), 2025, pp 1-10.
Download Paper

Fast and Gas-efficient Private Sealed-bid Auctions

发表于 PODC 2025

摘要 — In decentralized blockchain environments, auctions must ensure fairness, trustless execution and bid confidentiality while operating efficiently within resource-constrained smart contracts. We propose a new family of algorithms for private, trustless auctions that protect bidder identities and bid values while remaining practical for smart contract execution. Our approach builds on top of the Dutch auction model and a stepwise revelation tree. Bidders commit to their bids using cryptographic commitment schemes and later confirm their honest following of the protocol through zero-knowledge proofs, ensuring that only the highest bid is disclosed while all other bids remain (probabilistically) confidential. A key innovation is the use of a reveal tree, which structures the bidding process into logarithmically many rounds, reducing the total number of messages to $O(logn)$ and thereby significantly lowering gas costs and execution times. We further explore variants introducing fake bids to optimize our probabilistic privacy guarantees.

Recommended citation: J. Ballweg, A.K. Goharshady, Z. Lin, "Fast and Gas-efficient Private Sealed-bid Auctions," in 44th ACM Symposium on Principles of Distributed Computing (PODC), 2025, pp 169-172.
Download Paper

MPhil Thesis - Novel Blockchain-based Protocols for Electronic Voting and Auctions

发表于 香港科技大学 2025

摘要 — Programmable blockchains have long been a hot research topic given their tremendous use in decentralized applications. Smart contracts, using blockchains as their underlying technology, inherit the desired properties such as verifiability, immutability, and transparency, which make it a great suit in trustless environments.

Download Paper

Zhaorun Lin

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