Towards realizing random oracles: Hash functions that hide all partial information

Ran Canetti*

*Corresponding author for this work

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

177 Scopus citations

Abstract

The random oracle model is a very convenient setting for designing cryptographic protocols. In this idealized model all parties have access to a common, public random function, called a random oracle. Protocols in this model are often very simple and efficient; also the analysis is often clearer. However, we do not have a general mechanism for transforming protocols that are secure in the random oracle model into protocols that axe secure in real life. In fact, we do not even know how to meaningfully specify the properties required from such a mechanism. Instead, it is a common practice to simply replace - often without mathematical justification - the random oracle with a ‘cryptographic hash function’ (e.g., MD5 or SHA). Consequently, the resulting protocols have no meaningful proofs of security. We propose a research program aimed at rectifying this situation by means of identifying, and subsequently realizing, the useful properties of random oracles. As a first step, we introduce a new primitive that realizes a specific aspect of random oracles. This primitive, called oracle hashing, is a hash function that, like random oracles, 'hides all partial information on its input’. A salient property of oracle hashing is that it is probabilistic: different applications to the same input result in different hash values. Still, we maintain the ability to verify whether a given hash value was generated from a given input. We describe constructions of oracle hashing, as well as applications where oracle hashing successfully replaces random oracles.

Original languageEnglish
Title of host publicationAdvances in Cryptology — CRYPTO 1997 - 17th Annual International Cryptology Conference, Proceedings
EditorsB.S. Kaliski
PublisherSpringer Verlag
Pages454-469
Number of pages16
ISBN (Print)3540633847, 9783540633846
DOIs
StatePublished - 1997
Externally publishedYes
Event17th Annual International Cryptology Conference on Advances in Cryptology, CRYPTO 1997 - Santa Barbara, United States
Duration: 17 Aug 199721 Aug 1997

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume1294
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference17th Annual International Cryptology Conference on Advances in Cryptology, CRYPTO 1997
Country/TerritoryUnited States
CitySanta Barbara
Period17/08/9721/08/97

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