deterministic GenGaloisKeysNew?

[fedejinich]

Hi, I'm using this lattigo version, and I wanted to check about this situation

a := keygen.GenGaloisKeyNew(e, secretKey)
b := keygen.GenGaloisKeyNew(e, secretKey)

if !a.Equal(b) {
  panic("this is unexpected")
}

It surprised me that a is not equal to b (given the same galEl and secretKey). Is that expected? Is there any way to generate galois keys in a deterministic way (Ideally without marshalling into binary)

[ChristianMct]

This is an expected behavior. All (centralized) public-key generation functions are sampling "fresh" RLWE samples. I.e., they sample fresh public polynomial vector a and fresh secret error vector e at each call, so they output fresh keys (sa + X + e, a) (for X a variable that depends on the type of public key). There is currently no easy way to obtain a deterministic generation. The only way would be to re-implement the key-generation algo from the ring package, with seeded samplers.

That said, we are aware that this can be a problem, and we are planning to add the possibility of seeding the PRNGs behind our API.

[fedejinich]

Okay, thanks for the answer; very clear!