Signature keypair generation with external seed

[likakisp]

The library recently introduced new function OQS_KEM_keypair_derand that accepts a seed as input:
OQS_API OQS_STATUS OQS_KEM_keypair_derand(const OQS_KEM *kem, uint8_t *public_key, uint8_t *secret_key, const uint8_t *seed)

I don't see a similar API for signing algorithms such as ML-DSA that accept a seed as a parameter.

Do you plan to introduce such API any time soon?

If not, is there a preferred or documented method of adding new API calls to liboqs?

[SWilson4]

We've had prior requests for this feature, but we don't have anybody actively working on it. It's currently being tracked under liboqs issue #2030.

In principle, OQS_SIG_keypair_derand could be implemented in the same fashion as the corresponding KEM function. However, the upstream from which we draw our implementation of ML-DSA does not have a separate function for derandomized key generation. This means that we would have to patch the upstream code.

We plan to update the upstream to PQ Code Package's mldsa-native once that project has an stable release (maybe sooner, e.g., for a beta release). Their current work has derandomized keygen as a separate function, which would make it much easier to add the API in liboqs. As things stand, I would plan to expose keypair_derand for signatures after we make this update. If there is either significant demand for the feature to justify the additional dev work on our part or a well-written PR contributing the feature, I could see us moving it up in the timeline.