Cryptology ePrint Archive: Report 2015/1085

Malicious Keccak

Pawel Morawiecki

Abstract: In this paper, we investigate Keccak --- the cryptographic hash function adopted as the SHA-3 standard. We propose a malicious variant of the function, where new round constants are introduced. We show that for such the variant, collision and preimage attacks are possible. We also identify a class of weak keys for the malicious Keccak working in the MAC mode. Ideas presented in the paper were verified by implementing the attacks on the function with the 128-bit hash.

Category / Keywords: secret-key cryptography / cryptanalysis, Keccak, SHA-3, malicious hashing

Date: received 8 Nov 2015

Contact author: pawel morawiecki at gmail com

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Version: 20151109:092516 (All versions of this report)

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