Cryptology ePrint Archive: Report 2009/477

Preimages for Step-Reduced SHA-2

Jian Guo and Krystian Matusiewicz

Abstract: In this paper, we present a preimage attack for 42 step-reduced SHA-256 with time complexity $2^{251.7}$ and memory requirements of order $2^{12}$. The same attack also applies to 42 step-reduced SHA-512 with time complexity $2^{502.3}$ and memory requirements of order $2^{22}$. Our attack is meet-in-the-middle preimage attack.

Category / Keywords: secret-key cryptography / preimage attack, SHA-256, SHA-512, meet-in-the-middle, hash function

Publication Info: A merged version will appear in ASIACRYPT2009

Date: received 28 Sep 2009, last revised 1 Oct 2009

Contact author: guojian at ntu edu sg

Available format(s): PDF | BibTeX Citation

Version: 20091001:094831 (All versions of this report)

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