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# System prepended metadata

title: Ethereum cohort 4 - week 10

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# Ethereum cohort 4 - week 10

Updates for the week:
- feels like a productive week, pedersen hash is finally done per specs https://github.com/Quadratic-Labs/VerkleTries_Besu/pull/26 . Verkle tries lack a lot of documentation, this is definitely something that need to be worked on. Had a long call with https://github.com/thomas-quadratic regarding rust cryptography layer <-> Java trie logic layer. Although pedersen hash(PH) is the same as pedersen commitment(PC) - we are returning different values to the trie. For PH we return this: https://github.com/crate-crypto/banderwagon/blob/master/src/element.rs#L33 and for PC we return this: https://github.com/crate-crypto/banderwagon/blob/master/src/element.rs#L80 which is different and we can't do that in Java. Why is this designed in such way i don't know now, but will understand
- Discussed the idea of having poseidon as a hash instead of pedersen hash for trie-key generation the zk verkle telegram group. Will be interesting learning why this hash can't or can be replaced for pedersen hash and sha256 in fiat-shamir for verkle proof.
- Will learn more about poseidon for next week. My view is that it is becoming 