Cryptology ePrint Archive: Report 2008/043

Cryptanalysis of CRUSH hash structure

Nasour Bagheri, Majid Naderi, Babak Sadeghiyan

Abstract: In this paper, we will present a cryptanalysis of CRUSH hash structure. Surprisingly, our attack could find pre-image for any desired length of internal message. Time complexity of this attack is completely negligible. We will show that the time complexity of finding a pre-image of any length is O(1). In this attack, an adversary could freely find a pre-image with the length of his own choice for any given message digits. We can also find second pre-image, collision, multi-collision in the same complexity with our attack. In this paper, we also introduce a stronger variant of the algorithm, and show that an adversary could still be able to produce collisions for this stronger variant of CRUSH hash structure with a time complexity less than a Birthday attack.

Category / Keywords: secret-key cryptography / CRUSH hash structure, Hash function, Collision, Pre-image, Second pre-image, Multi-collision attack

Date: received 23 Jan 2008

Contact author: n_bagheri at iust ac ir

Available formats: PDF | BibTeX Citation

Version: 20080129:142144 (All versions of this report)

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