Cryptanalysis of a Cayley Hash Function Based on Affine Maps in one Variable over a Finite Field

The hash function proposed by Shpilrain and Sosnovski (Groups Complex Cryptol 8:155–161, 2016), based on affine maps in one variable over a finite field, was proven insecure for suggested parameters. This paper shows that the variation proposed by Ghaffari and Mostaghim (Groups Complex Cryptol 10:29–32, 2018) that uses Shpilrain and Sosnovski’s hash is also insecure. We demonstrate its security vulnerability by constructing collisions.