The random oracle methodology, revisited

Ran Canetti*, Oded Goldreich, Shai Halevi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We take a critical look at the relationship between the security of cryptographic schemes in the Random Oracle Model, and the security of the schemes that result from implementing the random oracle by so called "cryptographic hash functions". The main result of this article is a negative one: There exist signature and encryption schemes that are secure in the Random Oracle Model, but for which any implementation of the random oracle results in insecure schemes. In the process of devising the above schemes, we consider possible definitions for the notion of a "good implementation" of a random oracle, pointing out limitations and challenges.

Original languageEnglish
Pages (from-to)557-594
Number of pages38
JournalJournal of the ACM
Issue number4
StatePublished - Jul 2004
Externally publishedYes


  • CS-proofs
  • Correlation intractability
  • Cryptography
  • Diagonalization
  • The random-oracle model


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