S-FSB: An Improved Variant of the FSB Hash Family

In 2003, Augot et al. introduced the Fast Syndrome-Based hash family (in short FSB), which follows the generic construction of Merkle-Damg̊ard and is based on the syndrome decoding problem. In 2007, Finiasz et al. proposed an improved version of FSB. In this work, we propose a new efficient hash function, which incorporates the ideas of FSB and the sponge construction introduced by Bertoni et al. Our proposal is up to 30 % faster in practice than FSB. Its security is related on the Regular Syndrome (RSD) Decoding problem, which is proven NP-complete.