Sebastien Chapuis

@mitschabaude Thanks, I've tested that implementation in our Webnode, and we get ~40% faster in poseidon hashing: Hashing the full ledger (testnet) now takes 15 seconds, instead of 25 seconds....

@mitschabaude Indeed, I just [ported it](https://github.com/openmina/algebra/commit/6ca5fe8940ebbfe710601615655242ae89e17b0f) and we can hash the ledger in 14 seconds with this dedicated `square`, so total improvement is 44%. > not sure what you mean...