Expose zk-friendly hash functions

[ple1n]

Component

sp1-zkvm

Describe the feature you would like

and/or field arithmetic operations that they need.

ive been trying to make a sparse merkle tree that uses https://crates.io/crates/halo2_proofs

Additional context

No response

[leruaa]

@ple1n Can you elaborate a bit more what you need?

[ple1n]

@leruaa I was trying to build a sparse merkle tree over poseiden2 hash function with t=3 (which is lighter to compute but Idk if this 'non-native' field can be performant enough). I try to do it in the VM because this way others may use it inside their proofs and compose easily. And more rapid modification of the algo too.

And in general, I think it's better to just expose ZK-friendly hashes? It's absurd it's not done yet.

For reference, https://github.com/zkmove/smt-circuit It's not about me learning the cryptography I want my users to be able to make proofs easily with my code as a gadget

[mukeshdroid]

Any updates on this? @leruaa

We’re hitting the similar bottleneck: ~75 % of our proving cycles are spent computing SHA hashes while constructing a proof of correct garbling. A ZK-friendly hash would greatly help. We are using SHA simply because given its precompile, it is the cheapest hash function in terms of cycle count. Is this assumption correct?

I was also wondering if there is a fundamental blocker to exposing ZK-friendly hash like Poseidon to the guest?

[leruaa]

We are planning to add Poseidon precompile, I'll share here when I have more information on ETA.