Fully deniable interactive encryption

Ran Canetti, Sunoo Park, Oxana Poburinnaya

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


Deniable encryption (Canetti et al., Crypto 1996) enhances secret communication over public channels, providing the additional guarantee that the secrecy of communication is protected even if the parties are later coerced (or willingly bribed) to expose their entire internal states: plaintexts, keys and randomness. To date, constructions of deniable encryption—and more generally, interactive deniable communication—only address restricted cases where only one party is compromised (Sahai and Waters, STOC 2014). The main question—whether deniable communication is at all possible if both parties are coerced at once—has remained open. We resolve this question in the affirmative, presenting a communication protocol that is fully deniable under coercion of both parties. Our scheme has three rounds, assumes subexponentially secure indistinguishability obfuscation and one-way functions, and uses a short global reference string that is generated once at system set-up and suffices for an unbounded number of encryptions and decryptions. Of independent interest, we introduce a new notion called off-the-record deniability, which protects parties even when their claimed internal states are inconsistent (a case not covered by prior definitions). Our scheme satisfies both standard deniability and off-the-record deniability.

Original languageEnglish (US)
Title of host publicationAdvances in Cryptology - CRYPTO 2020 - 40th Annual International Cryptology Conference, CRYPTO 2020, Proceedings
EditorsDaniele Micciancio, Thomas Ristenpart
Number of pages29
ISBN (Print)9783030567835
StatePublished - 2020
Event40th Annual International Cryptology Conference, CRYPTO 2020 - Santa Barbara, United States
Duration: Aug 17 2020Aug 21 2020

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume12170 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference40th Annual International Cryptology Conference, CRYPTO 2020
Country/TerritoryUnited States
CitySanta Barbara

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Computer Science


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