Function classygroup::create_discriminant

pub fn create_discriminant<D, T>(seed: &[u8], length: u16) -> T where
    D: Digest + Default + FixedOutput,
    T: BigNumExt, 

Create a discriminant from a seed (a byte string) and a bit length (a u16). The discriminant is guaranteed to be a negative prime number that fits in length bits, except with negligible probability (less than 2^(-100)). It is also guaranteed to equal 7 modulo 8.

This function uses blake2b to expand the seed. Therefore, different seeds will result in completely different discriminants with overwhelming probability, unless length is very small. However, this function is deterministic: if it is called twice with identical seeds and lengths, it will always return the same discriminant.

This function is guaranteed not to panic for any inputs whatsoever, unless memory allocation fails and the allocator in use panics in that case.