Improved Threshold Signatures, Proactive Secret Sharing and Input Certification from LSS Isomorphisms

Diego F. Aranha, Anders Dalskov, Claudio Orlandi, Daniel Esteban Escudero Ospina*

*Corresponding author for this work

Research output: Contribution to book/anthology/report/proceedingArticle in proceedingsResearchpeer-review

Abstract

In this paper we present a series of applications steming from a formal treatment of linear secret-sharing isomorphisms, which are linear transformations between different secret-sharing schemes defined over vector spaces over a field F and allow for efficient multiparty conversion from one secret-sharing scheme to the other. This concept generalizes the folklore idea that moving from a secret-sharing scheme over F p to a secret sharing “in the exponent” can be done non-interactively by multiplying the share unto a generator of e.g., an elliptic curve group. We generalize this idea and show that it can also be used to compute arbitrary bilinear maps and in particular pairings over elliptic curves. We include the following practical applications originating from our framework: First we show how to securely realize the Pointcheval-Sanders signature scheme (CT-RSA 2016) in MPC. Second we present a construction for dynamic proactive secret-sharing which outperforms the current state of the art from CCS 2019. Third we present a construction for MPC input certification using digital signatures that we show experimentally to outperform the previous best solution in this area.

Original languageEnglish
Title of host publicationProgress in Cryptology – LATINCRYPT 2021
EditorsPatrick Longa, Carla Ràfols
Number of pages23
PublisherSpringer
Publication date2021
Pages382-404
ISBN (Print)9783030882372
DOIs
Publication statusPublished - 2021
Event7th International Conference on Cryptology and Information Security in Latin America - Bogotá, Colombia
Duration: 6 Oct 20218 Oct 2021
Conference number: 7
https://www.urosario.edu.co/Latin-Crypt-2020/inicio/

Conference

Conference7th International Conference on Cryptology and Information Security in Latin America
Number7
Country/TerritoryColombia
CityBogotá
Period06/10/202108/10/2021
Internet address
SeriesLecture Notes in Computer Science
Volume12912
ISSN0302-9743

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