Smash the singular Ciphersuite trait into multiple

This helps identify where the various functionalities are used, or rather, not
used. The `Ciphersuite` trait present in `patches/ciphersuite`, facilitating
the entire FCMP++ tree, only requires the markers _and_ canonical point
decoding. I've opened a PR to upstream such a trait into `group`
(https://github.com/zkcrypto/group/pull/68).

`WrappedGroup` is still justified for as long as `Group::generator` exists.
Moving `::generator()` to its own trait, on an independent structure (upstream)
would be massively appreciated. @tarcieri also wanted to update from
`fn generator()` to `const GENERATOR`, which would encourage further discussion
on https://github.com/zkcrypto/group/issues/32 and
https://github.com/zkcrypto/group/issues/45, which have been stagnant.

The `Id` trait is occasionally used yet really should be first off the chopping
block.

Finally, `WithPreferredHash` is only actually used around a third of the time,
which more than justifies it being a separate trait.

---

Updates `dalek_ff_group::Scalar` to directly re-export
`curve25519_dalek::Scalar`, as without issue. `dalek_ff_group::RistrettoPoint`
also could be replaced with an export of `curve25519_dalek::RistrettoPoint`,
yet the coordinator relies on how we implemented `Hash` on it for the hell of
it so it isn't worth it at this time. `dalek_ff_group::EdwardsPoint` can't be
replaced for an re-export of `curve25519_dalek::SubgroupPoint` as it doesn't
implement `zeroize`, `subtle` traits within a released, non-yanked version.
Relevance to https://github.com/serai-dex/serai/issues/201 and
https://github.com/dalek-cryptography/curve25519-dalek/issues/811#issuecomment-3247732746.

Also updates the `Ristretto` ciphersuite to prefer `Blake2b-512` over
`SHA2-512`. In order to maintain compliance with FROST's IETF standard,
`modular-frost` defines its own ciphersuite for Ristretto which still uses
`SHA2-512`.

tests/coordinator/src/lib.rs

@@ -16,7 +16,7 @@ use zeroize::Zeroizing;
 
 use ciphersuite::{
   group::{ff::PrimeField, GroupEncoding},
-  Ciphersuite,
+  WrappedGroup,
 };
 use dalek_ff_group::Ristretto;
 use embedwards25519::Embedwards25519;
@@ -39,7 +39,7 @@ mod tests;
 
 pub fn coordinator_instance(
   name: &str,
-  message_queue_key: <Ristretto as Ciphersuite>::F,
+  message_queue_key: <Ristretto as WrappedGroup>::F,
 ) -> TestBodySpecification {
   serai_docker_tests::build("coordinator".to_string());
 
@@ -123,7 +123,7 @@ pub struct Processor {
 
   evrf_public_keys: ([u8; 32], Vec<u8>),
 
-  substrate_key: Arc<AsyncMutex<Option<Zeroizing<<Ristretto as Ciphersuite>::F>>>>,
+  substrate_key: Arc<AsyncMutex<Option<Zeroizing<<Ristretto as WrappedGroup>::F>>>>,
 }
 
 impl Drop for Processor {
@@ -140,7 +140,7 @@ impl Processor {
     network: ExternalNetworkId,
     ops: &DockerOperations,
     handles: Handles,
-    processor_key: <Ristretto as Ciphersuite>::F,
+    processor_key: <Ristretto as WrappedGroup>::F,
   ) -> Processor {
     let message_queue_rpc = ops.handle(&handles.message_queue).host_port(2287).unwrap();
     let message_queue_rpc = format!("{}:{}", message_queue_rpc.0, message_queue_rpc.1);
@@ -321,7 +321,7 @@ impl Processor {
               schnorrkel_key_pair[.. 32].copy_from_slice(&substrate_key.to_repr());
               OsRng.fill_bytes(&mut schnorrkel_key_pair[32 .. 64]);
               schnorrkel_key_pair[64 ..].copy_from_slice(
-                &(<Ristretto as Ciphersuite>::generator() * *substrate_key).to_bytes(),
+                &(<Ristretto as WrappedGroup>::generator() * *substrate_key).to_bytes(),
               );
               let signature = Signature(
                 schnorrkel::keys::Keypair::from_bytes(&schnorrkel_key_pair)
@@ -390,7 +390,7 @@ impl Processor {
 
   pub async fn set_substrate_key(
     &mut self,
-    substrate_key: Zeroizing<<Ristretto as Ciphersuite>::F>,
+    substrate_key: Zeroizing<<Ristretto as WrappedGroup>::F>,
   ) {
     *self.substrate_key.lock().await = Some(substrate_key);
   }

tests/coordinator/src/tests/batch.rs

@@ -10,7 +10,7 @@ use blake2::{
   digest::{consts::U32, Digest},
   Blake2b,
 };
-use ciphersuite::{group::GroupEncoding, Ciphersuite}
+use ciphersuite::{group::GroupEncoding, WrappedGroup}
 use ciphersuite_kp256::Secp256k1;
 use dalek_ff_group::Ristretto;
 use dkg::Participant;
@@ -36,7 +36,7 @@ pub async fn batch(
   processors: &mut [Processor],
   processor_is: &[u8],
   session: Session,
-  substrate_key: &Zeroizing<<Ristretto as Ciphersuite>::F>,
+  substrate_key: &Zeroizing<<Ristretto as WrappedGroup>::F>,
   batch: Batch,
 ) -> u64 {
   let id = SubstrateSignId { session, id: SubstrateSignableId::Batch(batch.id), attempt: 0 };
@@ -164,7 +164,7 @@ pub async fn batch(
   schnorrkel_key_pair[.. 32].copy_from_slice(&substrate_key.to_repr());
   OsRng.fill_bytes(&mut schnorrkel_key_pair[32 .. 64]);
   schnorrkel_key_pair[64 ..]
-    .copy_from_slice(&(<Ristretto as Ciphersuite>::generator() * **substrate_key).to_bytes());
+    .copy_from_slice(&(<Ristretto as WrappedGroup>::generator() * **substrate_key).to_bytes());
   let signature = Signature(
     schnorrkel::keys::Keypair::from_bytes(&schnorrkel_key_pair)
       .unwrap()

tests/coordinator/src/tests/key_gen.rs

@@ -5,7 +5,7 @@ use rand_core::OsRng;
 
 use ciphersuite::{
   group::{ff::Field, GroupEncoding},
-  Ciphersuite,
+  WrappedGroup,
 };
 use ciphersuite_kp256::Secq256k1;
 use dalek_ff_group::Ristretto;
@@ -19,10 +19,10 @@ use messages::CoordinatorMessage;
 
 use crate::tests::*;
 
-pub async fn key_gen<C: Ciphersuite>(
+pub async fn key_gen<C: WrappedGroup>(
   processors: &mut [Processor],
   session: Session,
-) -> (Vec<u8>, Zeroizing<<Ristretto as Ciphersuite>::F>, Zeroizing<C::F>) {
+) -> (Vec<u8>, Zeroizing<<Ristretto as WrappedGroup>::F>, Zeroizing<C::F>) {
   let coordinators = processors.len();
   let mut participant_is = vec![];
 
@@ -93,8 +93,8 @@ pub async fn key_gen<C: Ciphersuite>(
   }
 
   // Now that we've received all participations, publish the key pair
-  let substrate_priv_key = Zeroizing::new(<Ristretto as Ciphersuite>::F::random(&mut OsRng));
-  let substrate_key = (<Ristretto as Ciphersuite>::generator() * *substrate_priv_key).to_bytes();
+  let substrate_priv_key = Zeroizing::new(<Ristretto as WrappedGroup>::F::random(&mut OsRng));
+  let substrate_key = (<Ristretto as WrappedGroup>::generator() * *substrate_priv_key).to_bytes();
 
   let network_priv_key = Zeroizing::new(C::F::random(&mut OsRng));
   let network_key = (C::generator() * *network_priv_key).to_bytes().as_ref().to_vec();

tests/coordinator/src/tests/mod.rs

@@ -1,6 +1,8 @@
 use core::future::Future;
 use std::{sync::OnceLock, collections::HashMap};
 
+use ciphersuite::WrappedGroup;
+
 use tokio::sync::Mutex;
 
 use dockertest::{
@@ -125,7 +127,7 @@ pub(crate) async fn new_test(test_body: impl TestBody, fast_epoch: bool) {
 
   struct Context {
     pending_coordinator_compositions: Mutex<Vec<TestBodySpecification>>,
-    handles_and_keys: Vec<(Handles, <Ristretto as Ciphersuite>::F)>,
+    handles_and_keys: Vec<(Handles, <Ristretto as WrappedGroup>::F)>,
     test_body: Box<dyn TestBody>,
   }
   static CONTEXT: OnceLock<Mutex<Option<Context>>> = OnceLock::new();