Add abstraction for the embedded elliptic curve keys

It's minimal but still pleasant.

substrate/validator-sets/Cargo.toml

@@ -21,22 +21,22 @@ bitvec = { version = "1", default-features = false, features = ["alloc", "serde"
 scale = { package = "parity-scale-codec", version = "3", default-features = false, features = ["derive", "bit-vec"] }
 scale-info = { version = "2", default-features = false, features = ["derive", "bit-vec"] }
 
-sp-core = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "74839cba4a7f48023080215e5194fd6ab7e270e5", default-features = false }
-sp-io = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "74839cba4a7f48023080215e5194fd6ab7e270e5", default-features = false }
-sp-runtime = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "74839cba4a7f48023080215e5194fd6ab7e270e5", default-features = false }
-sp-api = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "74839cba4a7f48023080215e5194fd6ab7e270e5", default-features = false }
+sp-core = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "ece373ca1e8aaee67844eebcca28b5e016136dba", default-features = false }
+sp-io = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "ece373ca1e8aaee67844eebcca28b5e016136dba", default-features = false }
+sp-runtime = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "ece373ca1e8aaee67844eebcca28b5e016136dba", default-features = false }
+sp-api = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "ece373ca1e8aaee67844eebcca28b5e016136dba", default-features = false }
 
-frame-system = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "74839cba4a7f48023080215e5194fd6ab7e270e5", default-features = false }
-frame-support = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "74839cba4a7f48023080215e5194fd6ab7e270e5", default-features = false }
+frame-system = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "ece373ca1e8aaee67844eebcca28b5e016136dba", default-features = false }
+frame-support = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "ece373ca1e8aaee67844eebcca28b5e016136dba", default-features = false }
 
 serai-primitives = { path = "../primitives", default-features = false, features = ["non_canonical_scale_derivations"] }
 
 coins-pallet = { package = "serai-coins-pallet", path = "../coins", default-features = false }
 
 [dev-dependencies]
-#pallet-timestamp = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "74839cba4a7f48023080215e5194fd6ab7e270e5", default-features = false }
+#pallet-timestamp = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "ece373ca1e8aaee67844eebcca28b5e016136dba", default-features = false }
 
-#sp-consensus-babe = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "74839cba4a7f48023080215e5194fd6ab7e270e5", default-features = false }
+#sp-consensus-babe = { git = "https://github.com/serai-dex/patch-polkadot-sdk", rev = "ece373ca1e8aaee67844eebcca28b5e016136dba", default-features = false }
 
 #ciphersuite = { path = "../../../crypto/ciphersuite", default-features = false, features = ["std"] }
 #dalek-ff-group = { path = "../../../crypto/dalek-ff-group", default-features = false, features = ["std"] }

substrate/validator-sets/src/embedded_elliptic_curve_keys.rs

@@ -0,0 +1,53 @@
+use sp_core::{Encode, sr25519::Public};
+
+use serai_primitives::{crypto::SignedEmbeddedEllipticCurveKeys, network_id::*};
+
+use frame_support::storage::StorageDoubleMap;
+
+pub(crate) trait EmbeddedEllipticCurveKeysStorage {
+  /// An opaque map storing keys on an embedded elliptic curve.
+  type EmbeddedEllipticCurveKeys: StorageDoubleMap<
+    ExternalNetworkId,
+    Public,
+    serai_primitives::crypto::EmbeddedEllipticCurveKeys,
+    Query = Option<serai_primitives::crypto::EmbeddedEllipticCurveKeys>,
+  >;
+}
+
+/// An interface for managing validators' embedded elliptic curve keys.
+pub(crate) trait EmbeddedEllipticCurveKeys {
+  /// Set a validator's embedded elliptic curve keys for an external network.
+  fn set_embedded_elliptic_curve_keys(
+    validator: Public,
+    keys: SignedEmbeddedEllipticCurveKeys,
+  ) -> Result<(), ()>;
+  /// Check if a validator still needs to set embedded elliptic curve keys.
+  fn still_needs_to_set_embedded_elliptic_curve_keys(network: NetworkId, validator: Public)
+    -> bool;
+}
+
+impl<S: EmbeddedEllipticCurveKeysStorage> EmbeddedEllipticCurveKeys for S {
+  /// Set a validator's embedded elliptic curve keys, for an external network.
+  fn set_embedded_elliptic_curve_keys(
+    validator: Public,
+    keys: SignedEmbeddedEllipticCurveKeys,
+  ) -> Result<(), ()> {
+    let keys = keys.verify(validator.into()).ok_or(())?;
+    S::EmbeddedEllipticCurveKeys::set(keys.network(), validator, Some(keys));
+    Ok(())
+  }
+
+  /// Check if a validator still needs to set embedded elliptic curve keys.
+  fn still_needs_to_set_embedded_elliptic_curve_keys(
+    network: NetworkId,
+    validator: Public,
+  ) -> bool {
+    match network {
+      // Validators never need to set embedded elliptic curve keys for Serai
+      NetworkId::Serai => return false,
+      NetworkId::External(network) => {
+        !S::EmbeddedEllipticCurveKeys::contains_key(network, validator)
+      }
+    }
+  }
+}

substrate/validator-sets/src/lib.rs

@@ -4,6 +4,9 @@
 
 extern crate alloc;
 
+mod embedded_elliptic_curve_keys;
+use embedded_elliptic_curve_keys::*;
+
 mod allocations;
 use allocations::*;
 
@@ -78,12 +81,7 @@ mod pallet {
   use frame_support::pallet_prelude::*;
 
   use serai_primitives::{
-    crypto::KeyPair,
-    network_id::*,
-    coin::*,
-    balance::*,
-    validator_sets::*,
-    address::SeraiAddress,
+    crypto::KeyPair, network_id::*, coin::*, balance::*, validator_sets::*, address::SeraiAddress,
   };
 
   use coins_pallet::Pallet as Coins;
@@ -91,8 +89,7 @@ mod pallet {
   use super::*;
 
   #[pallet::config]
-  #[pallet::disable_frame_system_supertrait_check]
-  pub trait Config: coins_pallet::Config {
+  pub trait Config: frame_system::Config + coins_pallet::Config {
     type RuntimeEvent: IsType<<Self as frame_system::Config>::RuntimeEvent> + From<Event<Self>>;
 
     // type ShouldEndSession: ShouldEndSession<BlockNumberFor<Self>>;
@@ -157,19 +154,24 @@ mod pallet {
   }
   */
 
-  /// A key on an embedded elliptic curve.
+  struct Abstractions<T: Config>(PhantomData<T>);
+
+  // Satisfy the `EmbeddedEllipticCurveKeys` abstraction
+
   #[pallet::storage]
-  pub type EmbeddedEllipticCurveKeys<T: Config> = StorageDoubleMap<
+  type EmbeddedEllipticCurveKeys<T: Config> = StorageDoubleMap<
     _,
-    Blake2_128Concat,
-    Public,
     Identity,
     ExternalNetworkId,
+    Blake2_128Concat,
+    Public,
     serai_primitives::crypto::EmbeddedEllipticCurveKeys,
     OptionQuery,
   >;
 
-  struct Abstractions<T: Config>(PhantomData<T>);
+  impl<T: Config> EmbeddedEllipticCurveKeysStorage for Abstractions<T> {
+    type EmbeddedEllipticCurveKeys = EmbeddedEllipticCurveKeys<T>;
+  }
 
   // Satisfy the `Allocations` abstraction
 
@@ -186,7 +188,7 @@ mod pallet {
     type SortedAllocations = SortedAllocations<T>;
   }
 
-  // Satisfy the `Sessions` API
+  // Satisfy the `Sessions` abstraction
 
   // We use `Identity` as the hasher for `NetworkId` due to how constrained it is
   #[pallet::storage]
@@ -809,12 +811,12 @@ mod pallet {
     #[pallet::weight(0)] // TODO
     pub fn set_embedded_elliptic_curve_keys(
       origin: OriginFor<T>,
-      network: ExternalNetworkId,
-      keys: serai_primitives::crypto::EmbeddedEllipticCurveKeys,
+      keys: serai_primitives::crypto::SignedEmbeddedEllipticCurveKeys,
     ) -> DispatchResult {
       let signer = ensure_signed(origin)?;
-      // TODO: Add PoKs and check validity
-      EmbeddedEllipticCurveKeys::<T>::set(signer, network, Some(keys));
+      <Abstractions<T> as crate::EmbeddedEllipticCurveKeys>::set_embedded_elliptic_curve_keys(
+        signer, keys,
+      )?;
       Ok(())
     }
 
@@ -824,10 +826,12 @@ mod pallet {
       let validator = ensure_signed(origin)?;
       // If this network utilizes embedded elliptic curve(s), require the validator to have set the
       // appropriate key(s)
-      if let Ok(network) = ExternalNetworkId::try_from(network) {
-        if !EmbeddedEllipticCurveKeys::<T>::contains_key(validator, network) {
-          Err(Error::<T>::MissingEmbeddedEllipticCurveKey)?;
-        }
+      if <
+        Abstractions::<T>
+          as
+        crate::EmbeddedEllipticCurveKeys
+      >::still_needs_to_set_embedded_elliptic_curve_keys(network, validator) {
+        Err(Error::<T>::MissingEmbeddedEllipticCurveKey)?;
       }
       Coins::<T>::transfer_internal(
         validator,

substrate/validator-sets/src/sessions.rs

@@ -44,7 +44,8 @@ pub(crate) trait SessionsStorage: AllocationsStorage {
   ///
   /// This is opaque and to be exclusively read/write by `Sessions`.
   // The value is how many key shares the validator has.
-  type SelectedValidators: StorageMap<SelectedValidatorsKey, u64> + StoragePrefixedMap<u64>;
+  type SelectedValidators: StorageMap<SelectedValidatorsKey, u64, Query = Option<u64>>
+    + StoragePrefixedMap<u64>;
 
   /// The total allocated stake for a network.
   ///