On symmetric encryption and point obfuscation

Ran Canetti, Yael Tauman Kalai, Mayank Varia, Daniel Wichs

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

Abstract

We show tight connections between several cryptographic primitives, namely encryption with weakly random keys, encryption with key-dependent messages (KDM), and obfuscation of point functions with multi-bit output (which we call multi-bit point functions, or MBPFs, for short). These primitives, which have been studied mostly separately in recent works, bear some apparent similarities, both in the flavor of their security requirements and in the flavor of their constructions and assumptions. Still, rigorous connections have not been drawn. Our results can be interpreted as indicating that MBPF obfuscators imply a very strong form of encryption that simultaneously achieves security for weakly-random keys and key-dependent messages as special cases. Similarly, each one of the other primitives implies a certain restricted form of MBPF obfuscation. Our results carry both constructions and impossibility results from one primitive to others. In particular: - The recent impossibility result for KDM security of Haitner and Holenstein (TCC '09) carries over to MBPF obfuscators. - The Canetti-Dakdouk construction of MBPF obfuscators based on a strong variant of the DDH assumption (EC '08) gives an encryption scheme which is secure w.r.t. any weak key distribution of super-logarithmic min-entropy (and in particular, also has very strong leakage resilient properties). - All the recent constructions of encryption schemes that are secure w.r.t. weak keys imply a weak form of MBPF obfuscators.

Original languageEnglish
Title of host publicationTheory of Cryptography - 7th Theory of Cryptography Conference, TCC 2010, Proceedings
PublisherSpringer Verlag
Pages52-71
Number of pages20
ISBN (Print)3642117988, 9783642117985
DOIs
StatePublished - 2010
Event7th Theory of Cryptography Conference, TCC 2010 - Zurich, Switzerland
Duration: 9 Feb 201011 Feb 2010

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume5978 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference7th Theory of Cryptography Conference, TCC 2010
Country/TerritorySwitzerland
CityZurich
Period9/02/1011/02/10

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