On the CCA Compatibility of Public-Key Infrastructure

Dakshita Khurana, Brent Waters

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

Abstract

In this work, we put forth the notion of compatibility of any key generation or setup algorithm. We focus on the specific case of encryption, and say that a key generation algorithm KeyGen is X-compatible (for X∈ { CPA, CCA1, CCA2} ) if there exist encryption and decryption algorithms that together with KeyGen, result in an X -secure public-key encryption scheme. We study the following question: Is every CPA-compatible key generation algorithm also CCA-compatible? We obtain the following answers: Every sub-exponentially CPA-compatible KeyGen algorithm is CCA1-compatible, assuming the existence of hinting PRGs and sub-exponentially secure keyless collision resistant hash functions.Every sub-exponentially CPA-compatible KeyGen algorithm is also CCA2-compatible, assuming the existence of non-interactive CCA2 secure commitments, in addition to sub-exponential security of the assumptions listed in the previous bullet. Here, sub-exponentially CPA-compatible KeyGen refers to any key generation algorithm for which there exist encryption and decryption algorithms that result in a CPA -secure public-key encryption scheme against sub-exponential adversaries. This gives a way to perform CCA secure encryption given any public key infrastructure that has been established with only (sub-exponential) CPA security in mind. The resulting CCA encryption makes black-box use of the CPA scheme and all other underlying primitives.

Original languageEnglish (US)
Title of host publicationPublic-Key Cryptography – PKC 2021 - 24th IACR International Conference on Practice and Theory of Public Key Cryptography, 2021, Proceedings
EditorsJuan A. Garay
PublisherSpringer
Pages235-260
Number of pages26
ISBN (Print)9783030752477
DOIs
StatePublished - 2021
Event24th IACR International Conference on Practice and Theory of Public Key Cryptography, PKC 2021 - Virtual, Online
Duration: May 10 2021May 13 2021

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume12711 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference24th IACR International Conference on Practice and Theory of Public Key Cryptography, PKC 2021
CityVirtual, Online
Period5/10/215/13/21

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Computer Science(all)

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