AnemoiSponge R1CS gadget #112
Description
Implement R1CS gadget for AnemoiSponge. This is the Sponge mode of operation of the Anemoi permutation [1]. It transforms Anemoi into a general purpose hash function like SHA3/Keccak, MimC, etc. with arbitrary size input and fixed but variable size output. See Sect. 3.1 in [1] for the full description.