Cryptology ePrint Archive: Report 2020/023

Threshold Multi-Signature with an Offline Recovery Party

Riccardo Longo and Alessio Meneghetti and Massimiliano Sala

Abstract: Key custody is a sensitive aspect of cryptocurrencies. The employment of a custodian service together with threshold-multi-party signatures helps to manage secret keys more safely and effectively, e.g. allowing the recovery of crypto-assets when users lose their own keys. Advancing from a protocol by Gennaro et al. we propose a protocol with two main properties. First it allows the recovery party to remain offline during the enrollment of any user, solving a real-life problem of maintaining online only one trusted third party. Second our multi-party signature is compatible with a deterministic derivation of public and private keys.

Category / Keywords: cryptographic protocols / digital signatures, threshold cryptography, secure multi-party computation, cryptocurrency, threshold signature, provable security

Date: received 7 Jan 2020, last revised 9 Jan 2020

Contact author: riccardolongomath at gmail com,almenegh@gmail com,maxsalacodes@gmail com

Available format(s): PDF | BibTeX Citation

Version: 20200109:160305 (All versions of this report)

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