Cryptology ePrint Archive: Report 2017/534

Functional Graph Revisited: Updates on (Second) Preimage Attacks on Hash Combiners

Zhenzhen Bao and Lei Wang and Jian Guo and Dawu Gu

Abstract: This paper studies functional-graph-based (second) preimage attacks against hash combiners. By exploiting more properties of cyclic nodes of functional graph, we find an improved preimage attack against the XOR combiner with a complexity of $2^{5n/8}$, while the previous best-known complexity is $2^{2n/3}$. Moreover, we find the first generic second-preimage attack on Zipper hash with an optimal complexity of $2^{3n/5}$.

Category / Keywords: Hash Combiner, Functional Graph, XOR Combiner, Zipper Hash, (Second) Preimage Attack

Original Publication (with minor differences): IACR-CRYPTO-2017

Date: received 5 Jun 2017, last revised 19 Aug 2017

Contact author: wanglei_hb at sjtu edu cn

Available format(s): PDF | BibTeX Citation

Note: Full version, revise the content regarding the expected number of trials reaching deep-iterates simultaneously

Version: 20170819:154727 (All versions of this report)

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