Enhancements are blackbox non-trivial: Impossibility of enhanced trapdoor permutations from standard trapdoor permutations

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


    Trapdoor permutations (TDP) are a fundamental primitive in cryptography. Several variants of this notion have emerged as a result of different applications. However, it is not clear whether these variants can be based on the standard notion of TDPs. We study the question of whether enhanced trapdoor permutations can be based on classical trapdoor permutations. The main motivation of our work is in the context of existing TDP-based constructions of oblivious transfer and non-interactive zero knowledge protocols, which require enhancements to the classical TDP notion. We prove that these enhancements are non-trivial, in the sense that there does not exist fully blackbox constructions of enhanced TDPs from classical TDPs. On the technical side, we show that the enhanced TDP security of any construction in the random TDP oracle world can be broken via a polynomial number of queries to the TDP oracle as well as a weakening oracle, which provides inversion with respect to randomness. We also show that the standard one-wayness of the random TDP oracle stays intact in the presence of this weakening oracle.

    Original languageEnglish (US)
    Title of host publicationTheory of Cryptography - 16th International Conference, TCC 2018, Proceedings
    EditorsAmos Beimel, Stefan Dziembowski
    PublisherSpringer Verlag
    Number of pages28
    ISBN (Print)9783030038069
    StatePublished - 2018
    Event16th Theory of Cryptography Conference, TCC 2018 - Panaji, India
    Duration: Nov 11 2018Nov 14 2018

    Publication series

    NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
    Volume11239 LNCS
    ISSN (Print)0302-9743
    ISSN (Electronic)1611-3349


    Conference16th Theory of Cryptography Conference, TCC 2018

    All Science Journal Classification (ASJC) codes

    • Theoretical Computer Science
    • Computer Science(all)


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