Cryptology ePrint Archive: Report 2011/652
Security Enhancement of the Vortex Family of Hash Functions
Shay Gueron and Michael Kounavis
Abstract: Vortex is a new family of one-way hash functions which has been submitted to the NIST SHA-3 competition. Its design is based on using the Rijndael block cipher round as a building block, and using a multiplication-based merging function to support fast
mixing in a small number of steps. Vortex is designed to be a fast hash function, when running on a processor that has AES acceleration and has a proven collision resistance [2]. Several attacks on Vortex have been recently published [3, 4, 5, 6] exploiting some structural
properties of its design, as presented in the version submitted to the SHA-3 competition. These are mainly ¯rst and second preimage attacks with time complexity below the ideal, as well as attempts to distinguish the Vortex output from random. In this paper we study
the root-cause of the attacks and propose few amendments to the Vortex structure, which eliminate the attacks without a®ecting its collision resistance and performance.
Category / Keywords:
Date: received 2 Dec 2011, last revised 16 Feb 2021
Contact author: michael_kounavis at hotmail com
Available format(s): PDF | BibTeX Citation
Note: changed main author contact info
Version: 20210216:192229 (All versions of this report)
Short URL: ia.cr/2011/652
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