Reduce the number of permutations in merkle tree leave hashing

[ericnordelo]

In the poseidon hasher we can use h(x,y)=hades(x,y,2), which is 1 permutation less compared to state.update(x).update(y).finalize(), since the latter adds a permutation whenever we transition from odd --> even # of arguments (so only one so far) + another one for finalization.

[0x471]

Hi, can I work on this issue? @ericnordelo

[ericnordelo]

Hi, can I work on this issue? @ericnordelo

Hi, sure! Feel free to open a PR.

[0x471]

Hey @ericnordelo. Please review the PR in your free time. I would be happy to adjust and work on it further accordingly