Bandwidth-efficient threshold EC-DSA revisited: Online/Offline Extensions, Identifiable Aborts Proactive and Adaptive Security
CASTAGNOS, Guilhem
Lithe and fast algorithmic number theory [LFANT]
Analyse cryptographique et arithmétique [CANARI]
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Lithe and fast algorithmic number theory [LFANT]
Analyse cryptographique et arithmétique [CANARI]
CASTAGNOS, Guilhem
Lithe and fast algorithmic number theory [LFANT]
Analyse cryptographique et arithmétique [CANARI]
< Reduce
Lithe and fast algorithmic number theory [LFANT]
Analyse cryptographique et arithmétique [CANARI]
Language
en
Article de revue
This item was published in
Theoretical Computer Science. 2023, vol. 939, p. 78-104
Elsevier
English Abstract
Due to their use in crypto-currencies, threshold ECDSA signatures have received much attention in recent years. Though efficient solutions now exist both for the two party, and the full threshold scenario, there is still ...Read more >
Due to their use in crypto-currencies, threshold ECDSA signatures have received much attention in recent years. Though efficient solutions now exist both for the two party, and the full threshold scenario, there is still much room for improvement, be it in terms of protocol functionality, strengthening security or further optimising efficiency. In the past few months, a range of protocols have been published, allowing for a non interactive-and hence extremely efficient-signing protocol; providing new features, such as identifiable aborts (parties can be held accountable if they cause the protocol to fail), fairness in the honest majority setting (all parties receive output or nobody does) and other properties. In some cases, security is proven in the strong simulation based model. We combine ideas from the aforementioned articles with the suggestion of Castagnos et al. (PKC 2020) to use the class group based CL framework so as to drastically reduce bandwidth consumption. Building upon this latter protocol we present a new, maliciously secure, full threshold ECDSA protocol that achieves additional features without sacrificing efficiency. Our most basic protocol boasts a non interactive signature algorithm and identifiable aborts. We also propose a more advanced variant that achieves adaptive security (for the n-out-of-n case) and proactive security. Our resulting constructions improve upon state of the art Paillier's based realizations achieving similar goals by up to a 10 factor in bandwidth consumption.Read less <
English Keywords
Threshold Cryptography
EC-DSA
Digital Signatures
Multi-Party Computation
Provable Security
Class Groups
European Project
Cryptography for Privacy and Integrity of Computation on Untrusted Machines
ANR Project
Calcul réparti sécurisé : Cryptographie, Combinatoire, Calcul Formel - ANR-21-CE39-0006
Secure computations - ANR-22-PECY-0003
Secure computations - ANR-22-PECY-0003
Origin
Hal imported