Vortex is a hash function that was first presented at ISC’2008, then submitted to the NIST SHA-3 competition after some modifications. This paper describes several attacks on both versions of Vortex, including collisions, second preimages, preimages, and distinguishers. Our attacks exploit flaws both in the high-level design and in the lower-level algorithms.
Jean-Philippe Aumasson, Orr Dunkelman, Florian Men