Use proper messages for ValidatorSets/InInstructions pallet

Provides a DST, and associated metadata as beneficial.

Also utilizes MuSig's context to session-bind. Since set_keys_messages also
binds to set, this is semi-redundant, yet that's appreciated.

substrate/client/tests/common/in_instructions.rs

@@ -1,12 +1,10 @@
-use scale::Encode;
-
 use sp_core::Pair;
 
 use serai_client::{
   primitives::insecure_pair_from_name,
   validator_sets::primitives::{Session, ValidatorSet},
   in_instructions::{
-    primitives::{Batch, SignedBatch},
+    primitives::{Batch, SignedBatch, batch_message},
     InInstructionsEvent,
   },
   Serai,
@@ -32,7 +30,7 @@ pub async fn provide_batch(batch: Batch) -> [u8; 32] {
 
   let block = publish_tx(&Serai::execute_batch(SignedBatch {
     batch: batch.clone(),
-    signature: pair.sign(&batch.encode()),
+    signature: pair.sign(&batch_message(&batch)),
   }))
   .await;
 

substrate/client/tests/common/validator_sets.rs

@@ -3,18 +3,16 @@ use std::collections::HashMap;
 use zeroize::Zeroizing;
 use rand_core::OsRng;
 
-use scale::Encode;
-
 use sp_core::{Pair, sr25519::Signature};
 
 use ciphersuite::{group::GroupEncoding, Ciphersuite, Ristretto};
-use frost::dkg::musig::*;
+use frost::dkg::musig::musig;
 use schnorrkel::Schnorrkel;
 
 use serai_client::{
   primitives::insecure_pair_from_name,
   validator_sets::{
-    primitives::{ValidatorSet, KeyPair},
+    primitives::{ValidatorSet, KeyPair, musig_context, musig_key, set_keys_message},
     ValidatorSetsEvent,
   },
   Serai,
@@ -31,7 +29,7 @@ pub async fn set_validator_set_keys(set: ValidatorSet, key_pair: KeyPair) -> [u8
   let public_key = <Ristretto as Ciphersuite>::read_G::<&[u8]>(&mut public.0.as_ref()).unwrap();
   assert_eq!(
     serai.get_validator_set_musig_key(set).await.unwrap().unwrap(),
-    musig_key::<Ristretto>(&[public_key]).unwrap().to_bytes()
+    musig_key(set, &[public]).0
   );
 
   let secret_key = <Ristretto as Ciphersuite>::read_F::<&[u8]>(
@@ -39,7 +37,8 @@ pub async fn set_validator_set_keys(set: ValidatorSet, key_pair: KeyPair) -> [u8
   )
   .unwrap();
   assert_eq!(Ristretto::generator() * secret_key, public_key);
-  let threshold_keys = musig::<Ristretto>(&Zeroizing::new(secret_key), &[public_key]).unwrap();
+  let threshold_keys =
+    musig::<Ristretto>(&musig_context(set), &Zeroizing::new(secret_key), &[public_key]).unwrap();
   assert_eq!(
     serai.get_validator_set_musig_key(set).await.unwrap().unwrap(),
     threshold_keys.group_key().to_bytes()
@@ -52,7 +51,7 @@ pub async fn set_validator_set_keys(set: ValidatorSet, key_pair: KeyPair) -> [u8
       Schnorrkel::new(b"substrate"),
       &HashMap::from([(threshold_keys.params().i(), threshold_keys.into())]),
     ),
-    &key_pair.encode(),
+    &set_keys_message(&set, &key_pair),
   );
 
   // Vote in a key pair

substrate/client/tests/validator_sets.rs

@@ -2,13 +2,10 @@ use rand_core::{RngCore, OsRng};
 
 use sp_core::{sr25519::Public, Pair};
 
-use ciphersuite::{group::GroupEncoding, Ciphersuite, Ristretto};
-use frost::dkg::musig::musig_key;
-
 use serai_client::{
   primitives::{NETWORKS, NetworkId, insecure_pair_from_name},
   validator_sets::{
-    primitives::{Session, ValidatorSet},
+    primitives::{Session, ValidatorSet, musig_key},
     ValidatorSetsEvent,
   },
   Serai,
@@ -56,12 +53,7 @@ serai_test!(
     assert_eq!(participants_ref, [(public, set_data.bond)].as_ref());
     assert_eq!(
       serai.get_validator_set_musig_key(set).await.unwrap().unwrap(),
-      musig_key::<Ristretto>(&[<Ristretto as Ciphersuite>::read_G::<&[u8]>(
-        &mut public.0.as_ref()
-      )
-      .unwrap()])
-      .unwrap()
-      .to_bytes()
+      musig_key(set, &[public]).0
     );
 
     let block = set_validator_set_keys(set, key_pair.clone()).await;