Finish routing the new key gen in the processor

Doesn't touch the tests, coordinator, nor Substrate yet.
`cargo +nightly fmt && cargo +nightly-2024-07-01 clippy --all-features -p serai-processor`
does pass.

crypto/dkg/src/evrf/mod.rs

@@ -238,11 +238,7 @@ pub struct EvrfDkg<C: EvrfCurve> {
     HashMap<Participant, HashMap<Participant, ([<C::EmbeddedCurve as Ciphersuite>::G; 2], C::F)>>,
 }
 
-impl<C: EvrfCurve> EvrfDkg<C>
-where
-  <<C as EvrfCurve>::EmbeddedCurve as Ciphersuite>::G:
-    DivisorCurve<FieldElement = <C as Ciphersuite>::F>,
-{
+impl<C: EvrfCurve> EvrfDkg<C> {
   // Form the initial transcript for the proofs.
   fn initial_transcript(
     invocation: [u8; 32],
@@ -497,10 +493,15 @@ where
       for i in valid.keys() {
         let evrf_public_key = evrf_public_keys[usize::from(u16::from(*i)) - 1];
 
-        // We remove all keys considered participating from the Vec in order to ensure they aren't
-        // counted multiple times. That could happen if a participant shares a key with another
-        // participant. While that's presumably some degree of invalid, we're robust against it
-        // regardless.
+        // Remove this key from the Vec to prevent double-counting
+        /*
+          Double-counting would be a risk if multiple participants shared an eVRF public key and
+          participated. This code does still allow such participants (in order to let participants
+          be weighted), and any one of them participating will count as all participating. This is
+          fine as any one such participant will be able to decrypt the shares for themselves and
+          all other participants, so this is still a key generated by an amount of participants who
+          could simply reconstruct the key.
+        */
         let start_len = evrf_public_keys.len();
         evrf_public_keys.retain(|key| *key != evrf_public_key);
         let end_len = evrf_public_keys.len();

crypto/dkg/src/evrf/proof.rs

@@ -29,7 +29,7 @@ use generalized_bulletproofs_ec_gadgets::*;
 
 /// A pair of curves to perform the eVRF with.
 pub trait EvrfCurve: Ciphersuite {
-  type EmbeddedCurve: Ciphersuite;
+  type EmbeddedCurve: Ciphersuite<G: DivisorCurve<FieldElement = <Self as Ciphersuite>::F>>;
   type EmbeddedCurveParameters: DiscreteLogParameters;
 }
 
@@ -67,11 +67,7 @@ fn sample_point<C: Ciphersuite>(rng: &mut (impl RngCore + CryptoRng)) -> C::G {
 #[derive(Clone, Debug)]
 pub struct EvrfGenerators<C: EvrfCurve>(pub(crate) Generators<C>);
 
-impl<C: EvrfCurve> EvrfGenerators<C>
-where
-  <<C as EvrfCurve>::EmbeddedCurve as Ciphersuite>::G:
-    DivisorCurve<FieldElement = <C as Ciphersuite>::F>,
-{
+impl<C: EvrfCurve> EvrfGenerators<C> {
   /// Create a new set of generators.
   pub fn new(max_threshold: u16, max_participants: u16) -> EvrfGenerators<C> {
     let g = C::generator();
@@ -117,11 +113,7 @@ impl<C: EvrfCurve> fmt::Debug for EvrfVerifyResult<C> {
 
 /// A struct to prove/verify eVRFs with.
 pub(crate) struct Evrf<C: EvrfCurve>(PhantomData<C>);
-impl<C: EvrfCurve> Evrf<C>
-where
-  <<C as EvrfCurve>::EmbeddedCurve as Ciphersuite>::G:
-    DivisorCurve<FieldElement = <C as Ciphersuite>::F>,
-{
+impl<C: EvrfCurve> Evrf<C> {
   // Sample uniform points (via rejection-sampling) on the embedded elliptic curve
   fn transcript_to_points(
     seed: [u8; 32],

crypto/evrf/divisors/src/lib.rs

@@ -15,10 +15,7 @@ pub use poly::*;
 mod tests;
 
 /// A curve usable with this library.
-pub trait DivisorCurve: Group
-where
-  Self::Scalar: PrimeField,
-{
+pub trait DivisorCurve: Group {
   /// An element of the field this curve is defined over.
   type FieldElement: PrimeField;