KUPY-NEEV HASH FUNCTION

Abstract

Kupyna has been approved as a new cryptographic standard hash function of Ukrain in 2015 (Ukrainian standard DSTU 7564:2014).  It is built on the transformations of Kalyna block cipher (Ukrainian standard DSTU 7624:2014).  The design of compression function of Kupyna is nearly identical with Grøstl that makes it vulnerable to the similar attacks those were introduced on Grøstl.  It is adapted for its highly secured design and its efficiency but lately Mendel et al. [4] and Zou et al. [14] mountedrebound attack on compression function of Kupyna-256 and reduced round collision attack on Kupyna hash function respectively.  These attacks are applied on Kupyna because of its permutations based on AES.  In this paper we propose Kupy-Neev hash function in which we change those permutations with the permutations based on Neeva Hash [1].