Semantic security and indistinguishability in the quantum world

T. Gagliardoni, A.T. Hülsing, C. Schaffner

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

21 Citations (Scopus)

Abstract

At CRYPTO 2013, Boneh and Zhandry initiated the study of quantum-secure encryption. They proposed first indistinguishability definitions for the quantum world where the actual indistinguishability only holds for classical messages, and they provide arguments why it might be hard to achieve a stronger notion. In this work, we show that stronger notions are achievable, where the indistinguishability holds for quantum superpositions of messages. We investigate exhaustively the possibilities and subtle differences in defining such a quantum indistinguishability notion for symmetric-key encryption schemes. We justify our stronger definition by showing its equivalence to novel quantum semantic-security notions that we introduce. Furthermore, we show that our new security definitions cannot be achieved by a large class of ciphers – those which are quasi-preserving the message length. On the other hand, we provide a secure construction based on quantum-resistant pseudorandom permutations; this construction can be used as a generic transformation for turning a large class of encryption schemes into quantum indistinguishable and hence quantum semantically secure ones. Moreover, our construction is the first completely classical encryption scheme shown to be secure against an even stronger notion of indistinguishability, which was previously known to be achievable only by using quantum messages and arbitrary quantum encryption circuits.

Original languageEnglish
Title of host publicationAdvances in Cryptology – CRYPTO 2016
Subtitle of host publication36th Annual International Cryptology Conference, Santa Barbara, CA, USA, August 14-18, 2016, Proceedings, Part III
EditorsM. Robshaw, J. Katz
Place of PublicationDordrecht
PublisherSpringer
Pages60-89
Number of pages30
ISBN (Electronic)978-3-662-53015-3
ISBN (Print)978-3-662-53014-6
DOIs
Publication statusPublished - 2016
Event36th Annual International Cryptology Conference, CRYPTO 2016 - Santa Barbara, United States
Duration: 14 Aug 201618 Aug 2016

Publication series

NameLecture Notes in Computer Science
Volume9816
ISSN (Print)03029743
ISSN (Electronic)16113349

Conference

Conference36th Annual International Cryptology Conference, CRYPTO 2016
CountryUnited States
CitySanta Barbara
Period14/08/1618/08/16

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