Compact Ring Signatures from Learning with Errors

Rohit Chatterjee, Sanjam Garg, Mohammad Hajiabadi, Dakshita Khurana, Xiao Liang, Giulio Malavolta, Omkant Pandey, Sina Shiehian

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    Ring signatures allow a user to sign a message on behalf of a “ring” of signers, while hiding the true identity of the signer. As the degree of anonymity guaranteed by a ring signature is directly proportional to the size of the ring, an important goal in cryptography is to study constructions that minimize the size of the signature as a function of the number of ring members. In this work, we present the first compact ring signature scheme (i.e., where the size of the signature grows logarithmically with the size of the ring) from the (plain) learning with errors (LWE) problem. The construction is in the standard model and it does not rely on a common random string or on the random oracle heuristic. In contrast with the prior work of Backes et al. [EUROCRYPT’2019], our scheme does not rely on bilinear pairings, which allows us to show that the scheme is post-quantum secure assuming the quantum hardness of LWE. At the heart of our scheme is a new construction of compact and statistically witness indistinguishable ZAP arguments for NP ∩ coNP, that we show to be sound based on the plain LWE assumption. Prior to our work, statistical ZAPs (for all of NP) were known to exist only assuming sub-exponential LWE. We believe that this scheme might find further applications in the future.

    Original languageEnglish (US)
    Title of host publicationAdvances in Cryptology – CRYPTO 2021 - 41st Annual International Cryptology Conference, CRYPTO 2021, Proceedings
    EditorsTal Malkin, Chris Peikert
    PublisherSpringer Science and Business Media Deutschland GmbH
    Pages282-312
    Number of pages31
    ISBN (Print)9783030842413
    DOIs
    StatePublished - 2021
    Event41st Annual International Cryptology Conference, CRYPTO 2021 - Virtual, Online
    Duration: Aug 16 2021Aug 20 2021

    Publication series

    NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
    Volume12825 LNCS
    ISSN (Print)0302-9743
    ISSN (Electronic)1611-3349

    Conference

    Conference41st Annual International Cryptology Conference, CRYPTO 2021
    CityVirtual, Online
    Period8/16/218/20/21

    All Science Journal Classification (ASJC) codes

    • Theoretical Computer Science
    • Computer Science(all)

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