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Improved Indifferentiability Security Bound for the JH Mode



Dustin Moody, Souradyuti Paul, Daniel C. Smith-Tone


The JH hash function is one of the five fi nalists of the ongoing NIST SHA3 hash function competition. Despite several earlier attempts, and years of analysis, the indi fferentiability security bound of the JH mode has so far remained remarkably low, only up to n/3 bits [7]. Using a recent technique introduced by Moody, Paul and Smith-Tone in [23], we are now able to improve the bound of JH to n/2 bits. This means that the JH hash function should be able to resist generic attacks with work-factor less than O(2^n/2). Our rigorous experiments have given ample evidence that the bound could be further improved, possibly up to 2n/3 bits, or more. Theoretical analysis of this experimental result is left as an open problem.
Proceedings Title
Conference Dates
March 22-23, 2012
Conference Location
Washington D.C., DC
Conference Title
The Third SHA-3 Candidate Conference


Hash functions, indifferentiability, SHA-3


Moody, D. , Paul, S. and Smith-Tone, D. (2012), Improved Indifferentiability Security Bound for the JH Mode, None, Washington D.C., DC, [online], (Accessed July 15, 2024)


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Created March 22, 2012, Updated February 19, 2017