Support more hash functions to generate the public key in the eddsa-poseidon package

[cedoor]

Is your feature request related to a problem? Please describe.

This implementation of EdDSA is mostly based on the circomlibjs library, which uses BLAKE1-512 to derive the public key from the private key, probably because performance is more important in this context than security. RFC 8032 suggests using SHA-512 (presumably SHA3-512 nowadays), and BLAKE1 is starting to get out of date. It might make sense to offer devs more solutions.

Describe the solution you'd like

The package may use conditional exports and offer several versions of the same implementation using different hash functions. The default export could be the one with the best hash function in terms of security and performance (with more emphasis on performance), probably BLAKE2.

Devs may import EdDSAPoseidon in the following way:

import { EdDSAPoseidon } from "@zk-kit/eddsa-poseidon" // Default, BLAKE2

import { EdDSAPoseidon } from "@zk-kit/eddsa-poseidon/blake-1" // BLAKE1

import { EdDSAPoseidon } from "@zk-kit/eddsa-poseidon/sha-3" // SHA3

Describe alternatives you've considered

The functions and class exported from the package may take an additional parameter to define the hash function to be used. The default one could be the best one in terms of security and performance (with more emphasis on performance), probably BLAKE2.

The parameter could be part of an options object, where other parameters could be added in the future.

Additional context

• SHA
• BLAKE
• RCF 8032 - Key Generation
• BLAKE1 vs SHA3
• BLAKE1 vs BLAKE2
• BLAKE2 JavaScript implementation
• SHA3 JavaScript implementation

[hannahredler]

Hey! I'm Hannah, a dev currently studying the core program with the PSE team. I would be interested in picking this up!

My approach:

• I would choose one new algorithm to start, probably Blake2.
• I would implement this algorithm via the spec and set it as the default.
• I would add the additional ability to configure/ choose an alternative algorithm (at this point, to revert to Blake1)
• Then, in subsequent PRs, I would add the additional algorithms.

If you would be happy for me to go ahead, it would be great if you could let me know if you know of any implementations of the above algorithms that could be used, or whether it would be required to research/implement this too

[cedoor]

Hey @hannahredler, great! I'll assign this task to you :)

I think a good blake2 implementation could be: https://github.com/dcposch/blakejs.

sha3: https://github.com/emn178/js-sha3.

Conditional exports should be the right way to go.