T-Watch: Towards Timed Execution of Private Transaction in Blockchains
<|reference_start|>T-Watch: Towards Timed Execution of Private Transaction in Blockchains: In blockchains such as Bitcoin and Ethereum, transactions represent the primary mechanism that the external world can use to trigger a change of blockchain state. Transactions serve as key sources of evidence and play a vital role in forensic analysis. Timed transaction refers to a specific class of service that enables a user to schedule a transaction to change the blockchain state during a chosen future time-frame. This paper proposes T-Watch, a decentralized and cost-efficient approach for users to schedule timed execution of any type of transaction in Ethereum with privacy guarantees. T-Watch employs a novel combination of threshold secret sharing and decentralized smart contracts. To protect the private elements of a scheduled transaction from getting disclosed before the future time-frame, T-Watch maintains shares of the decryption key of the scheduled transaction using a group of executors recruited in a blockchain network before the specified future time-frame and restores the scheduled transaction at a proxy smart contract to trigger the change of blockchain state at the required time-frame. To reduce the cost of smart contract execution in T-Watch, we carefully design the proposed protocol to run in an optimistic mode by default and then switch to a pessimistic mode once misbehaviors occur. Furthermore, the protocol supports users to form service request pooling to further reduce the gas cost. We rigorously analyze the security of T-Watch and implement the protocol over the Ethereum official test network. The results demonstrate that T-Watch is more scalable compared to the state of the art and could reduce the cost by over 90% through pooling.<|reference_end|>
@article{li2024t-watch:,
    title={T-Watch: Towards Timed Execution of Private Transaction in Blockchains},
    author={Chao Li and Balaji Palanisamy},
    journal={arXiv preprint arXiv:2405.08268},
    year={2024},
    archivePrefix={arXiv},
    eprint={2405.08268},
    primaryClass={cs.CR cs.DC}
}