Verifiable Encrypted Timed Signature Scheme and Its Application in Blockchains

Le résumé fourni par la source

Verifiable Timed Signatures (CCS '20) add a verification feature to timed signatures. Before spending computing effort, a solver can check that the timed signature contains a valid signature. Because of this, VTS has been used in distributed protocols such as atomic swaps and payment channels on scriptless blockchains. But in existing VTS schemes, the solver can start solving as soon as the timed signature is received. This can cause problems when solving should start only after a certain condition is met. In an atomic swap, for example, a malicious initiator with high-performance hardware could solve the timed signature faster than the counterparty anticipates, thereby threatening the security of the counterparty's funds. While increasing the time parameter can mitigate this threat, it does so at the cost of prolonged lock-up periods for ordinary users, resulting in high opportunity costs. In this work, we propose Verifiable Encrypted Timed Signatures (VETS), a new cryptographic tool. It separates public verification from time-based extraction. Anyone can check that the encapsulated signature is valid, but no one can extract it by performing the sequential computation alone. Extraction is possible only after an unlock key is released, and this key can be tied to an outside event or condition. We show how to use VETS by designing an atomic swap protocol. In this protocol, the initiator can start solving the timed signature only after the counterparty publishes the refund transaction. Therefore, the initiator cannot extract the hidden signature before the refund transaction is published, even if the initiator has high-performance hardware. Meanwhile, this “publish-then-solve” paradigm can reduce the opportunity costs of the initiator. In addition to atomic swaps, we believe this tool can also be used in other settings, such as payment channels and delayed payments.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.