Cryptology ePrint Archive: Report 2015/114

Weak Ideal Functionalities for Designing Random Oracles with Applications to Fugue

Shai Halevi, William E. Hall, Charanjit S. Jutla, Arnab Roy

Abstract: We define ideal functionalities that are weaker than ideal functionalities traditionally used in realizing variable input length (VIL) random oracles (RO) in the indifferentiability or universal-Composability (UC) model. We also show realization of VIL-RO using these weaker ideal functionalities, with applications to proving Fugue and CubeHash hash functions to be VIL-RO. We argue that components of Fugue realize this weaker ideal functionality using techniques employed in proving resistance of Fugue to differential collision-attacks. This should be contrasted with other hash functions that are proven VIL-RO assuming the components are extremely ideal, e.g. random permutations.

Category / Keywords: secret-key cryptography / Fugue, Random Oracle, UC, Hash Function

Date: received 14 Feb 2015, last revised 23 Feb 2015

Contact author: csjutla at us ibm com

Available format(s): PDF | BibTeX Citation

Note: Added Contact address.

Version: 20150224:031810 (All versions of this report)

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