Higher-Order Differential Properties of Keccak and Luffa
Higher-Order Differential Properties of Keccak and Luffa
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DOI:
10.1007/978-3-642-21702-9_15
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发表时间:
2011-02
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影响因子:
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通讯作者:
Christina Boura;A. Canteaut;C. Cannière
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文献类型:
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作者:
Christina Boura;A. Canteaut;C. Cannière
In this paper, we identify higher-order differential and zero-sum properties in the fullKeccak-fpermutation, in theLuffav1 hash function and in components of theLuffav2 algorithm. These structural properties rely on a new bound on the degree of iterated permutations with a nonlinear layer composed of parallel applications of a number of balanced Sboxes. These techniques yield zero-sum partitions of size 21575for the fullKeccak-fpermutation and several observations on theLuffahash family. We first show thatLuffav1 applied to one-block messages is a function of 255 variables with degree at most 251. This observation leads to the construction of a higher-order differential distinguisher for the fullLuffav1 hash function, similar to the one presented by Watanabeet al.on a reduced version. We show that similar techniques can be used to find all-zero higher-order differentials in theLuffav2 compression function, but the additional blank round destroys this property in the hash function.