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Fast threshold ECDSA with honest majority

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ECDSA is a widely adopted digital signature standard. A number of threshold protocols for ECDSA have been developed that let a set of parties jointly generate the secret signing key and compute signatures, without ever revealing the signing key. Threshold protocols for ECDSA have seen recent interest, in particular due to the need for additional security in cryptocurrency wallets where leakage of the signing key is equivalent to an immediate loss of money. We propose a threshold ECDSA protocol secure against an active adversary in the honest majority model with abort. Our protocol is efficient in terms of both computation and bandwidth usage, and it allows the parties to pre-process parts of the signature, such that once the message to sign becomes known, the they can compute a secret sharing of the signature very efficiently, using only local operations. We also show how to obtain fairness in the online phase at the cost of some additional work in the pre-processing, i.e., such that it either aborts during pre-processing phase, in which case nothing is revealed, or the signature is guaranteed to be delivered to all honest parties.

Original languageEnglish
Title of host publicationSecurity and Cryptography for Networks
EditorsClemente Galdi, Vladimir Kolesnikov
Number of pages19
Place of publicationCham
Publication year2020
ISBN (print)9783030579890
ISBN (electronic)978-3-030-57990-6
Publication statusPublished - 2020
Event12th International Conference on Security and Cryptography for Networks, SCN 2020 - Amalfi, Italy
Duration: 14 Sept 202016 Sept 2020


Conference12th International Conference on Security and Cryptography for Networks, SCN 2020
SeriesLecture Notes in Computer Science

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