feat: verifier returns all outputs rather than their hash

[tdelabro]

The fact that the verifier returns the hash of the output rather than the full outputs prevents a lot of use cases.
Eg. I want to accept a proof in my application if and only if the value written in the inputs is the pubkey that belong to a set I maintain. With only the hash I won't be able to check if this pubkey belong to my set.

This is a breaking change.
People who rely on the old behavior (hash of all outputs) of this lib will have to compute the hash themselves.

Sidenote:

• There is room for code factorization between the different layouts.
• It would theoretically be possible to return an iterator over &Felt instead of a Vec. This would avoid both collecting and cloning the returned values but at the cost of more complexity in the trait.

[Okm165]

We can export program hash and output hash util functions in the project for people to use (in couple flavors: pedersen, poseidon and keccak for example). Also wondering if raw program byte-code could be returned for sake of symmetry so user could just pass it to util function in his project lmk wdyt?

The byte-code is there in raw form we should have a way to extract it raw imo as we do with output.

[tdelabro]

#59 provides it for the program hash
I can also factorize and export the output_hash in this one.

About the byte-code I'm not sure.
From my perspective, as a user of the verifier, I just want to provide the proof, get a bool and the output, and that is all.
But maybe I'm missing a use-case here

[tdelabro]

So after checking it appears that the method to compute the hash of the output (once returned as a vec) already exists in the ecosystem:

pedersen:
https://github.com/xJonathanLEI/starknet-rs/blob/8755b68675f103ee011f1d964fcec55f1902fa09/starknet-core/src/crypto.rs#L66
poseidon:
https://github.com/xJonathanLEI/starknet-rs/blob/8755b68675f103ee011f1d964fcec55f1902fa09/starknet-crypto/src/poseidon_hash.rs#L72

Whatever method I can expose will just be a wrapper over those. Maybe it's not useful to reexpose those in swiftness.

[Okm165]

You are right lets have just logic for extraction of program and output to Vec<Felt> in swiftness then in examples we can present hashing these with https://github.com/xJonathanLEI/starknet-rs utils so we don't redefine anything

[tdelabro]

@Okm165 do you want to merge this, or has there been a change in plan?

[Okm165]

@tdelabro i think good idea would be to add example of calculating hash with starknet-rs tools so users before this breaking change are not lost when this changes apply
I guess good place is here https://github.com/iosis-tech/swiftness/blob/main/cli/src/main.rs

[tdelabro]

I can add an --hash-output argument to the program to that if it is passed, you will get the hash instead of the array. Wdyt?

[Okm165]

That is great solution

[tdelabro]

@Okm165 I pushed the CLI new arg

[Okm165]

LGTM