Trapdoor functions from the computational diffie-hellman assumption

Sanjam Garg, Mohammad Hajiabadi

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

    18 Scopus citations


    Trapdoor functions (TDFs) are a fundamental primitive in cryptography. Yet, the current set of assumptions known to imply TDFs is surprisingly limited, when compared to public-key encryption. We present a new general approach for constructing TDFs. Specifically, we give a generic construction of TDFs from any Chameleon Encryption (Döttling and Garg [CRYPTO’17]) satisfying a novel property which we call recyclability. By showing how to adapt current Computational Diffie-Hellman (CDH) based constructions of chameleon encryption to yield recyclability, we obtain the first construction of TDFs with security proved under the CDH assumption. While TDFs from the Decisional Diffie-Hellman (DDH) assumption were previously known, the possibility of basing them on CDH had remained open for more than 30 years.

    Original languageEnglish (US)
    Title of host publicationAdvances in Cryptology – CRYPTO 2018 - 38th Annual International Cryptology Conference, 2018, Proceedings
    EditorsAlexandra Boldyreva, Hovav Shacham
    PublisherSpringer Verlag
    Number of pages30
    ISBN (Print)9783319968803
    StatePublished - 2018
    Event38th Annual International Cryptology Conference, CRYPTO 2018 - Santa Barbara, United States
    Duration: Aug 19 2018Aug 23 2018

    Publication series

    NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
    Volume10992 LNCS
    ISSN (Print)0302-9743
    ISSN (Electronic)1611-3349


    Conference38th Annual International Cryptology Conference, CRYPTO 2018
    Country/TerritoryUnited States
    CitySanta Barbara

    All Science Journal Classification (ASJC) codes

    • Theoretical Computer Science
    • General Computer Science


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