diff --git a/Cargo.lock b/Cargo.lock
index 2a77bc9be..b9646cc55 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -7862,7 +7862,6 @@ dependencies = [
  "serai-in-instructions-primitives",
  "serai-primitives",
  "serai-validator-sets-primitives",
- "zeroize",
 ]
 
 [[package]]
diff --git a/common/db/src/create_db.rs b/common/db/src/create_db.rs
index 0b0cb0100..1c5bfad1e 100644
--- a/common/db/src/create_db.rs
+++ b/common/db/src/create_db.rs
@@ -51,12 +51,10 @@ macro_rules! create_db {
             ($($arg),*).encode()
           )
         }
-        #[allow(dead_code)]
         pub fn set(txn: &mut impl DbTxn $(, $arg: $arg_type)*, data: &$field_type) {
           let key = $field_name::key($($arg),*);
           txn.put(&key, borsh::to_vec(data).unwrap());
         }
-        #[allow(dead_code)]
         pub fn get(getter: &impl Get, $($arg: $arg_type),*) -> Option<$field_type> {
           getter.get($field_name::key($($arg),*)).map(|data| {
             borsh::from_slice(data.as_ref()).unwrap()
diff --git a/coordinator/src/db.rs b/coordinator/src/db.rs
index 7be798b62..d8ec4356e 100644
--- a/coordinator/src/db.rs
+++ b/coordinator/src/db.rs
@@ -34,18 +34,12 @@ impl<D: Db> MainDb<D> {
     getter.get(Self::handled_message_key(network, id)).is_some()
   }
 
-  fn in_tributary_key(set: ValidatorSet) -> Vec<u8> {
-    Self::main_key(b"in_tributary", set.encode())
-  }
   fn active_tributaries_key() -> Vec<u8> {
     Self::main_key(b"active_tributaries", [])
   }
   fn retired_tributary_key(set: ValidatorSet) -> Vec<u8> {
     Self::main_key(b"retired_tributary", set.encode())
   }
-  pub fn in_tributary<G: Get>(getter: &G, set: ValidatorSet) -> bool {
-    getter.get(Self::in_tributary_key(set)).is_some()
-  }
   pub fn active_tributaries<G: Get>(getter: &G) -> (Vec<u8>, Vec<TributarySpec>) {
     let bytes = getter.get(Self::active_tributaries_key()).unwrap_or(vec![]);
     let mut bytes_ref: &[u8] = bytes.as_ref();
@@ -58,8 +52,6 @@ impl<D: Db> MainDb<D> {
     (bytes, tributaries)
   }
   pub fn add_participating_in_tributary(txn: &mut D::Transaction<'_>, spec: &TributarySpec) {
-    txn.put(Self::in_tributary_key(spec.set()), []);
-
     let key = Self::active_tributaries_key();
     let (mut existing_bytes, existing) = Self::active_tributaries(txn);
     for tributary in &existing {
diff --git a/coordinator/src/main.rs b/coordinator/src/main.rs
index 194a9cee5..f766d5240 100644
--- a/coordinator/src/main.rs
+++ b/coordinator/src/main.rs
@@ -57,7 +57,7 @@ pub mod processors;
 use processors::Processors;
 
 mod substrate;
-use substrate::{CosignTransactions, SubstrateDb};
+use substrate::CosignTransactions;
 
 mod cosign_evaluator;
 use cosign_evaluator::CosignEvaluator;
@@ -116,7 +116,7 @@ async fn add_tributary<D: Db, Pro: Processors, P: P2p>(
     .send(
       set.network,
       processor_messages::key_gen::CoordinatorMessage::GenerateKey {
-        id: processor_messages::key_gen::KeyGenId { set, attempt: 0 },
+        id: processor_messages::key_gen::KeyGenId { session: set.session, attempt: 0 },
         params: frost::ThresholdParams::new(spec.t(), spec.n(), our_i.start).unwrap(),
         shares: u16::from(our_i.end) - u16::from(our_i.start),
       },
@@ -195,66 +195,50 @@ async fn handle_processor_message<D: Db, P: P2p>(
     // We'll only receive these if we fired GenerateKey, which we'll only do if if we're
     // in-set, making the Tributary relevant
     ProcessorMessage::KeyGen(inner_msg) => match inner_msg {
-      key_gen::ProcessorMessage::Commitments { id, .. } => Some(id.set.session),
-      key_gen::ProcessorMessage::InvalidCommitments { id, .. } => Some(id.set.session),
-      key_gen::ProcessorMessage::Shares { id, .. } => Some(id.set.session),
-      key_gen::ProcessorMessage::InvalidShare { id, .. } => Some(id.set.session),
-      key_gen::ProcessorMessage::GeneratedKeyPair { id, .. } => Some(id.set.session),
-      key_gen::ProcessorMessage::Blame { id, .. } => Some(id.set.session),
+      key_gen::ProcessorMessage::Commitments { id, .. } => Some(id.session),
+      key_gen::ProcessorMessage::InvalidCommitments { id, .. } => Some(id.session),
+      key_gen::ProcessorMessage::Shares { id, .. } => Some(id.session),
+      key_gen::ProcessorMessage::InvalidShare { id, .. } => Some(id.session),
+      key_gen::ProcessorMessage::GeneratedKeyPair { id, .. } => Some(id.session),
+      key_gen::ProcessorMessage::Blame { id, .. } => Some(id.session),
     },
     // TODO: Review replacing key with Session in messages?
     ProcessorMessage::Sign(inner_msg) => match inner_msg {
       // We'll only receive InvalidParticipant/Preprocess/Share if we're actively signing
-      sign::ProcessorMessage::InvalidParticipant { id, .. } => {
-        Some(SubstrateDb::<D>::session_for_key(&txn, &id.key).unwrap())
-      }
-      sign::ProcessorMessage::Preprocess { id, .. } => {
-        Some(SubstrateDb::<D>::session_for_key(&txn, &id.key).unwrap())
-      }
-      sign::ProcessorMessage::Share { id, .. } => {
-        Some(SubstrateDb::<D>::session_for_key(&txn, &id.key).unwrap())
-      }
+      sign::ProcessorMessage::InvalidParticipant { id, .. } => Some(id.session),
+      sign::ProcessorMessage::Preprocess { id, .. } => Some(id.session),
+      sign::ProcessorMessage::Share { id, .. } => Some(id.session),
       // While the Processor's Scanner will always emit Completed, that's routed through the
       // Signer and only becomes a ProcessorMessage::Completed if the Signer is present and
       // confirms it
-      sign::ProcessorMessage::Completed { key, .. } => {
-        Some(SubstrateDb::<D>::session_for_key(&txn, key).unwrap())
-      }
+      sign::ProcessorMessage::Completed { session, .. } => Some(*session),
     },
     ProcessorMessage::Coordinator(inner_msg) => match inner_msg {
-      // This is a special case as it's relevant to *all* Tributaries for this network
+      // This is a special case as it's relevant to *all* Tributaries for this network we're
+      // signing in
       // It doesn't return a Tributary to become `relevant_tributary` though
-      coordinator::ProcessorMessage::SubstrateBlockAck { network, block, plans } => {
-        assert_eq!(
-          *network, msg.network,
-          "processor claimed to be a different network than it was for SubstrateBlockAck",
-        );
-
+      coordinator::ProcessorMessage::SubstrateBlockAck { block, plans } => {
         // Get the sessions for these keys
-        let keys = plans.iter().map(|plan| plan.key.clone()).collect::<HashSet<_>>();
-        let mut sessions = vec![];
-        for key in keys {
-          let session = SubstrateDb::<D>::session_for_key(&txn, &key).unwrap();
-          // Only keep them if we're in the Tributary AND they haven't been retied
-          let set = ValidatorSet { network: *network, session };
-          if MainDb::<D>::in_tributary(&txn, set) && (!MainDb::<D>::is_tributary_retired(&txn, set))
-          {
-            sessions.push((session, key));
-          }
-        }
+        let sessions = plans
+          .iter()
+          .map(|plan| plan.session)
+          .filter(|session| {
+            !MainDb::<D>::is_tributary_retired(&txn, ValidatorSet { network, session: *session })
+          })
+          .collect::<HashSet<_>>();
 
         // Ensure we have the Tributaries
-        for (session, _) in &sessions {
+        for session in &sessions {
           if !tributaries.contains_key(session) {
             return false;
           }
         }
 
-        for (session, key) in sessions {
+        for session in sessions {
           let tributary = &tributaries[&session];
           let plans = plans
             .iter()
-            .filter_map(|plan| Some(plan.id).filter(|_| plan.key == key))
+            .filter_map(|plan| Some(plan.id).filter(|_| plan.session == session))
             .collect::<Vec<_>>();
           PlanIds::set(&mut txn, &tributary.spec.genesis(), *block, &plans);
 
@@ -286,18 +270,10 @@ async fn handle_processor_message<D: Db, P: P2p>(
         None
       }
       // We'll only fire these if we are the Substrate signer, making the Tributary relevant
-      coordinator::ProcessorMessage::InvalidParticipant { id, .. } => {
-        Some(SubstrateDb::<D>::session_for_key(&txn, &id.key).unwrap())
-      }
-      coordinator::ProcessorMessage::CosignPreprocess { id, .. } => {
-        Some(SubstrateDb::<D>::session_for_key(&txn, &id.key).unwrap())
-      }
-      coordinator::ProcessorMessage::BatchPreprocess { id, .. } => {
-        Some(SubstrateDb::<D>::session_for_key(&txn, &id.key).unwrap())
-      }
-      coordinator::ProcessorMessage::SubstrateShare { id, .. } => {
-        Some(SubstrateDb::<D>::session_for_key(&txn, &id.key).unwrap())
-      }
+      coordinator::ProcessorMessage::InvalidParticipant { id, .. } => Some(id.session),
+      coordinator::ProcessorMessage::CosignPreprocess { id, .. } => Some(id.session),
+      coordinator::ProcessorMessage::BatchPreprocess { id, .. } => Some(id.session),
+      coordinator::ProcessorMessage::SubstrateShare { id, .. } => Some(id.session),
       coordinator::ProcessorMessage::CosignedBlock { block_number, block, signature } => {
         let cosigned_block = CosignedBlock {
           network,
@@ -462,11 +438,6 @@ async fn handle_processor_message<D: Db, P: P2p>(
           }]
         }
         key_gen::ProcessorMessage::InvalidShare { id, accuser, faulty, blame } => {
-          assert_eq!(
-            id.set.network, msg.network,
-            "processor claimed to be a different network than it was for in InvalidShare",
-          );
-
           // Check if the MuSig signature had any errors as if so, we need to provide
           // RemoveParticipant
           // As for the safety of calling error_generating_key_pair, the processor is presumed
@@ -490,11 +461,7 @@ async fn handle_processor_message<D: Db, P: P2p>(
           txs
         }
         key_gen::ProcessorMessage::GeneratedKeyPair { id, substrate_key, network_key } => {
-          assert_eq!(
-            id.set.network, msg.network,
-            "processor claimed to be a different network than it was for in GeneratedKeyPair",
-          );
-          // TODO2: Also check the other KeyGenId fields
+          // TODO2: Check the KeyGenId fields
 
           // Tell the Tributary the key pair, get back the share for the MuSig signature
           let share = crate::tributary::generated_key_pair::<D>(
@@ -514,11 +481,9 @@ async fn handle_processor_message<D: Db, P: P2p>(
             }
           }
         }
-        key_gen::ProcessorMessage::Blame { id, participant } => {
-          assert_eq!(
-            id.set.network, msg.network,
-            "processor claimed to be a different network than it was for in Blame",
-          );
+        // This is a response to the ordered VerifyBlame, which is why this satisfies the provided
+        // transaction's needs to be perfectly ordered
+        key_gen::ProcessorMessage::Blame { id: _, participant } => {
           vec![Transaction::RemoveParticipant(participant)]
         }
       },
@@ -556,7 +521,7 @@ async fn handle_processor_message<D: Db, P: P2p>(
             signed: Transaction::empty_signed(),
           })]
         }
-        sign::ProcessorMessage::Completed { key: _, id, tx } => {
+        sign::ProcessorMessage::Completed { session: _, id, tx } => {
           let r = Zeroizing::new(<Ristretto as Ciphersuite>::F::random(&mut OsRng));
           #[allow(non_snake_case)]
           let R = <Ristretto as Ciphersuite>::generator() * r.deref();
diff --git a/coordinator/src/substrate/db.rs b/coordinator/src/substrate/db.rs
index b1c4c1c2b..02fe65cf9 100644
--- a/coordinator/src/substrate/db.rs
+++ b/coordinator/src/substrate/db.rs
@@ -1,12 +1,12 @@
-use scale::{Encode, Decode};
-
-pub use serai_db::*;
+use scale::Encode;
 
 use serai_client::{
   primitives::NetworkId,
-  validator_sets::primitives::{Session, ValidatorSet, KeyPair},
+  validator_sets::primitives::{Session, ValidatorSet},
 };
 
+pub use serai_db::*;
+
 create_db! {
   SubstrateDb {
     CosignTriggered: () -> (),
@@ -86,24 +86,6 @@ impl<D: Db> SubstrateDb<D> {
     txn.put(Self::event_key(&id, index), []);
   }
 
-  fn session_key(key: &[u8]) -> Vec<u8> {
-    Self::substrate_key(b"session", key)
-  }
-  pub fn session_for_key<G: Get>(getter: &G, key: &[u8]) -> Option<Session> {
-    getter.get(Self::session_key(key)).map(|bytes| Session::decode(&mut bytes.as_ref()).unwrap())
-  }
-  pub fn save_session_for_keys(txn: &mut D::Transaction<'_>, key_pair: &KeyPair, session: Session) {
-    let session = session.encode();
-    let key_0 = Self::session_key(&key_pair.0);
-    let existing = txn.get(&key_0);
-    // This may trigger if 100% of a DKG are malicious, and they create a key equivalent to a prior
-    // key. Since it requires 100% maliciousness, not just 67% maliciousness, this will only assert
-    // in a modified-to-be-malicious stack, making it safe
-    assert!(existing.is_none() || (existing.as_ref() == Some(&session)));
-    txn.put(key_0, session.clone());
-    txn.put(Self::session_key(&key_pair.1), session);
-  }
-
   fn batch_instructions_key(network: NetworkId, id: u32) -> Vec<u8> {
     Self::substrate_key(b"batch", (network, id).encode())
   }
diff --git a/coordinator/src/substrate/mod.rs b/coordinator/src/substrate/mod.rs
index 85272970a..d304db704 100644
--- a/coordinator/src/substrate/mod.rs
+++ b/coordinator/src/substrate/mod.rs
@@ -30,7 +30,7 @@ use tokio::{sync::mpsc, time::sleep};
 use crate::{
   Db,
   processors::Processors,
-  tributary::{TributarySpec, SeraiBlockNumber, KeyPairDb},
+  tributary::{TributarySpec, SeraiBlockNumber},
 };
 
 mod db;
@@ -116,19 +116,13 @@ async fn handle_new_set<D: Db>(
   Ok(())
 }
 
-async fn handle_key_gen<D: Db, Pro: Processors>(
-  db: &mut D,
+async fn handle_key_gen<Pro: Processors>(
   processors: &Pro,
   serai: &Serai,
   block: &Block,
   set: ValidatorSet,
   key_pair: KeyPair,
 ) -> Result<(), SeraiError> {
-  // This has to be saved *before* we send ConfirmKeyPair
-  let mut txn = db.txn();
-  SubstrateDb::<D>::save_session_for_keys(&mut txn, &key_pair, set.session);
-  txn.commit();
-
   processors
     .send(
       set.network,
@@ -144,7 +138,7 @@ async fn handle_key_gen<D: Db, Pro: Processors>(
             // block which has a time greater than or equal to the Serai time
             .unwrap_or(BlockHash([0; 32])),
         },
-        set,
+        session: set.session,
         key_pair,
       },
     )
@@ -232,7 +226,6 @@ async fn handle_batch_and_burns<D: Db, Pro: Processors>(
             serai_time: block.time().unwrap() / 1000,
             network_latest_finalized_block,
           },
-          network,
           block: block.number(),
           burns: burns.remove(&network).unwrap(),
           batches: batches.remove(&network).unwrap(),
@@ -291,13 +284,7 @@ async fn handle_block<D: Db, Pro: Processors>(
     if !SubstrateDb::<D>::handled_event(&db.0, hash, event_id) {
       log::info!("found fresh key gen event {:?}", key_gen);
       if let ValidatorSetsEvent::KeyGen { set, key_pair } = key_gen {
-        // Immediately ensure this key pair is accessible to the tributary, before we fire any
-        // events off of it
-        let mut txn = db.0.txn();
-        KeyPairDb::set(&mut txn, set, &key_pair);
-        txn.commit();
-
-        handle_key_gen(&mut db.0, processors, serai, &block, set, key_pair).await?;
+        handle_key_gen(processors, serai, &block, set, key_pair).await?;
       } else {
         panic!("KeyGen event wasn't KeyGen: {key_gen:?}");
       }
diff --git a/coordinator/src/tests/tributary/dkg.rs b/coordinator/src/tests/tributary/dkg.rs
index c429a7542..83ec99118 100644
--- a/coordinator/src/tests/tributary/dkg.rs
+++ b/coordinator/src/tests/tributary/dkg.rs
@@ -132,7 +132,7 @@ async fn dkg_test() {
     assert_eq!(
       msgs.pop_front().unwrap(),
       CoordinatorMessage::KeyGen(key_gen::CoordinatorMessage::Commitments {
-        id: KeyGenId { set: spec.set(), attempt: 0 },
+        id: KeyGenId { session: spec.set().session, attempt: 0 },
         commitments: expected_commitments
       })
     );
@@ -150,7 +150,7 @@ async fn dkg_test() {
     assert_eq!(
       msgs.pop_front().unwrap(),
       CoordinatorMessage::KeyGen(key_gen::CoordinatorMessage::Commitments {
-        id: KeyGenId { set: spec.set(), attempt: 0 },
+        id: KeyGenId { session: spec.set().session, attempt: 0 },
         commitments: expected_commitments
       })
     );
@@ -214,7 +214,7 @@ async fn dkg_test() {
   // Each scanner should emit a distinct shares message
   let shares_for = |i: usize| {
     CoordinatorMessage::KeyGen(key_gen::CoordinatorMessage::Shares {
-      id: KeyGenId { set: spec.set(), attempt: 0 },
+      id: KeyGenId { session: spec.set().session, attempt: 0 },
       shares: vec![txs
         .iter()
         .enumerate()
@@ -267,7 +267,7 @@ async fn dkg_test() {
     assert_eq!(
       msgs.pop_front().unwrap(),
       CoordinatorMessage::KeyGen(key_gen::CoordinatorMessage::Commitments {
-        id: KeyGenId { set: spec.set(), attempt: 0 },
+        id: KeyGenId { session: spec.set().session, attempt: 0 },
         commitments: expected_commitments
       })
     );
diff --git a/coordinator/src/tributary/db.rs b/coordinator/src/tributary/db.rs
index 6b6d01ede..c48a2311f 100644
--- a/coordinator/src/tributary/db.rs
+++ b/coordinator/src/tributary/db.rs
@@ -5,7 +5,7 @@ use zeroize::Zeroizing;
 use ciphersuite::{Ciphersuite, Ristretto, group::GroupEncoding};
 use frost::Participant;
 
-use serai_client::validator_sets::primitives::{ValidatorSet, KeyPair};
+use serai_client::validator_sets::primitives::KeyPair;
 
 use processor_messages::coordinator::SubstrateSignableId;
 
@@ -50,7 +50,6 @@ create_db!(
     PlanIds: (genesis: &[u8], block: u64) -> Vec<[u8; 32]>,
     ConfirmationNonces: (genesis: [u8; 32], attempt: u32) -> HashMap<Participant, Vec<u8>>,
     CurrentlyCompletingKeyPair: (genesis: [u8; 32]) -> KeyPair,
-    KeyPairDb: (set: ValidatorSet) -> KeyPair,
     AttemptDb: (genesis: [u8; 32], topic: &Topic) -> u32,
     DataReceived: (genesis: [u8; 32], data_spec: &DataSpecification) -> u16,
     DataDb: (genesis: [u8; 32], data_spec: &DataSpecification, signer_bytes: &[u8; 32]) -> Vec<u8>,
diff --git a/coordinator/src/tributary/handle.rs b/coordinator/src/tributary/handle.rs
index 7b94b0654..bb9152c9d 100644
--- a/coordinator/src/tributary/handle.rs
+++ b/coordinator/src/tributary/handle.rs
@@ -30,7 +30,7 @@ use crate::{
     nonce_decider::NonceDecider,
     dkg_confirmer::DkgConfirmer,
     scanner::{RecognizedIdType, RIDTrait},
-    FatallySlashed, DkgShare, PlanIds, ConfirmationNonces, KeyPairDb, AttemptDb, DataDb,
+    FatallySlashed, DkgShare, PlanIds, ConfirmationNonces, AttemptDb, DataDb,
   },
 };
 
@@ -260,7 +260,7 @@ pub(crate) async fn handle_application_tx<
             .send(
               spec.set().network,
               key_gen::CoordinatorMessage::Commitments {
-                id: KeyGenId { set: spec.set(), attempt },
+                id: KeyGenId { session: spec.set().session, attempt },
                 commitments,
               },
             )
@@ -397,7 +397,7 @@ pub(crate) async fn handle_application_tx<
             .send(
               spec.set().network,
               key_gen::CoordinatorMessage::Shares {
-                id: KeyGenId { set: spec.set(), attempt },
+                id: KeyGenId { session: spec.set().session, attempt },
                 shares: expanded_shares,
               },
             )
@@ -443,7 +443,7 @@ pub(crate) async fn handle_application_tx<
         .send(
           spec.set().network,
           key_gen::CoordinatorMessage::VerifyBlame {
-            id: KeyGenId { set: spec.set(), attempt },
+            id: KeyGenId { session: spec.set().session, attempt },
             accuser,
             accused: faulty,
             share,
@@ -504,15 +504,6 @@ pub(crate) async fn handle_application_tx<
         SubstrateSignableId::CosigningSubstrateBlock(hash),
       );
 
-      let key = loop {
-        let Some(key_pair) = KeyPairDb::get(txn, spec.set()) else {
-          // This can happen based on a timing condition
-          log::warn!("CosignSubstrateBlock yet keys weren't set yet");
-          tokio::time::sleep(core::time::Duration::from_secs(1)).await;
-          continue;
-        };
-        break key_pair.0.into();
-      };
       let block_number = SeraiBlockNumber::get(txn, hash)
         .expect("CosignSubstrateBlock yet didn't save Serai block number");
       processors
@@ -520,7 +511,7 @@ pub(crate) async fn handle_application_tx<
           spec.set().network,
           coordinator::CoordinatorMessage::CosignSubstrateBlock {
             id: SubstrateSignId {
-              key,
+              session: spec.set().session,
               id: SubstrateSignableId::CosigningSubstrateBlock(hash),
               attempt: 0,
             },
@@ -579,12 +570,15 @@ pub(crate) async fn handle_application_tx<
         Accumulation::Ready(DataSet::Participating(mut preprocesses)) => {
           unflatten(spec, &mut preprocesses);
           NonceDecider::selected_for_signing_substrate(txn, genesis, data.plan);
-          let key = KeyPairDb::get(txn, spec.set()).unwrap().0 .0;
           processors
             .send(
               spec.set().network,
               coordinator::CoordinatorMessage::SubstratePreprocesses {
-                id: SubstrateSignId { key, id: data.plan, attempt: data.attempt },
+                id: SubstrateSignId {
+                  session: spec.set().session,
+                  id: data.plan,
+                  attempt: data.attempt,
+                },
                 preprocesses: preprocesses
                   .into_iter()
                   .map(|(k, v)| (k, v.try_into().unwrap()))
@@ -613,12 +607,15 @@ pub(crate) async fn handle_application_tx<
       ) {
         Accumulation::Ready(DataSet::Participating(mut shares)) => {
           unflatten(spec, &mut shares);
-          let key = KeyPairDb::get(txn, spec.set()).unwrap().0 .0;
           processors
             .send(
               spec.set().network,
               coordinator::CoordinatorMessage::SubstrateShares {
-                id: SubstrateSignId { key, id: data.plan, attempt: data.attempt },
+                id: SubstrateSignId {
+                  session: spec.set().session,
+                  id: data.plan,
+                  attempt: data.attempt,
+                },
                 shares: shares
                   .into_iter()
                   .map(|(validator, share)| (validator, share.try_into().unwrap()))
@@ -636,7 +633,6 @@ pub(crate) async fn handle_application_tx<
       let Ok(_) = check_sign_data_len::<D>(txn, spec, data.signed.signer, data.data.len()) else {
         return;
       };
-      let key_pair = KeyPairDb::get(txn, spec.set());
       match handle(
         txn,
         &DataSpecification {
@@ -654,14 +650,7 @@ pub(crate) async fn handle_application_tx<
             .send(
               spec.set().network,
               sign::CoordinatorMessage::Preprocesses {
-                id: SignId {
-                  key: key_pair
-                    .expect("completed SignPreprocess despite not setting the key pair")
-                    .1
-                    .into(),
-                  id: data.plan,
-                  attempt: data.attempt,
-                },
+                id: SignId { session: spec.set().session, id: data.plan, attempt: data.attempt },
                 preprocesses,
               },
             )
@@ -675,7 +664,6 @@ pub(crate) async fn handle_application_tx<
       let Ok(_) = check_sign_data_len::<D>(txn, spec, data.signed.signer, data.data.len()) else {
         return;
       };
-      let key_pair = KeyPairDb::get(txn, spec.set());
       match handle(
         txn,
         &DataSpecification {
@@ -692,14 +680,7 @@ pub(crate) async fn handle_application_tx<
             .send(
               spec.set().network,
               sign::CoordinatorMessage::Shares {
-                id: SignId {
-                  key: key_pair
-                    .expect("completed SignShares despite not setting the key pair")
-                    .1
-                    .into(),
-                  id: data.plan,
-                  attempt: data.attempt,
-                },
+                id: SignId { session: spec.set().session, id: data.plan, attempt: data.attempt },
                 shares,
               },
             )
@@ -727,13 +708,15 @@ pub(crate) async fn handle_application_tx<
       };
 
       // TODO: Confirm this signer hasn't prior published a completion
-      let Some(key_pair) = KeyPairDb::get(txn, spec.set()) else {
-        panic!("SignCompleted for recognized plan ID despite not having a key pair for this set")
-      };
+
       processors
         .send(
           spec.set().network,
-          sign::CoordinatorMessage::Completed { key: key_pair.1.to_vec(), id: plan, tx: tx_hash },
+          sign::CoordinatorMessage::Completed {
+            session: spec.set().session,
+            id: plan,
+            tx: tx_hash,
+          },
         )
         .await;
     }
diff --git a/message-queue/src/main.rs b/message-queue/src/main.rs
index cbb8772eb..c3ca70039 100644
--- a/message-queue/src/main.rs
+++ b/message-queue/src/main.rs
@@ -69,12 +69,7 @@ mod binaries {
     // Assert one, and only one of these, is the coordinator
     assert!(matches!(meta.from, Service::Coordinator) ^ matches!(meta.to, Service::Coordinator));
 
-    // Verify (from, intent) hasn't been prior seen
-    // At the time of writing, intents should be unique even across `from`. There's a DoS where
-    // a service sends another service's intent, causing the other service to have their message
-    // dropped though.
-    // Including from prevents that DoS, and allows simplifying intents to solely unique within
-    // a service (not within all of Serai).
+    // Verify (from, to, intent) hasn't been prior seen
     fn key(domain: &'static [u8], key: impl AsRef<[u8]>) -> Vec<u8> {
       [&[u8::try_from(domain.len()).unwrap()], domain, key.as_ref()].concat()
     }
diff --git a/processor/Cargo.toml b/processor/Cargo.toml
index 000eedf08..a95567f3f 100644
--- a/processor/Cargo.toml
+++ b/processor/Cargo.toml
@@ -54,6 +54,7 @@ tokio = { version = "1", default-features = false, features = ["rt-multi-thread"
 
 serai-db = { path = "../common/db", features = ["rocksdb"], optional = true }
 serai-env = { path = "../common/env", optional = true }
+# TODO: Replace with direct usage of primitives
 serai-client = { path = "../substrate/client", default-features = false }
 
 messages = { package = "serai-processor-messages", path = "./messages", optional = true }
diff --git a/processor/messages/Cargo.toml b/processor/messages/Cargo.toml
index 6856dab9f..a3611193d 100644
--- a/processor/messages/Cargo.toml
+++ b/processor/messages/Cargo.toml
@@ -14,8 +14,6 @@ all-features = true
 rustdoc-args = ["--cfg", "docsrs"]
 
 [dependencies]
-zeroize = { version = "1", default-features = false, features = ["std", "derive"] }
-
 scale = { package = "parity-scale-codec", version = "3", default-features = false, features = ["std"] }
 borsh = { version = "1", default-features = false, features = ["std", "derive", "de_strict_order"] }
 
diff --git a/processor/messages/src/lib.rs b/processor/messages/src/lib.rs
index 8f01a3d61..fe4f8f892 100644
--- a/processor/messages/src/lib.rs
+++ b/processor/messages/src/lib.rs
@@ -1,18 +1,16 @@
 use std::collections::HashMap;
 
-use zeroize::Zeroize;
-
 use scale::{Encode, Decode};
 use borsh::{BorshSerialize, BorshDeserialize};
 
 use dkg::{Participant, ThresholdParams};
 
-use serai_primitives::{BlockHash, NetworkId};
+use serai_primitives::BlockHash;
 use in_instructions_primitives::{Batch, SignedBatch};
 use coins_primitives::OutInstructionWithBalance;
-use validator_sets_primitives::{ValidatorSet, KeyPair};
+use validator_sets_primitives::{Session, KeyPair};
 
-#[derive(Clone, Copy, PartialEq, Eq, Debug, Zeroize, BorshSerialize, BorshDeserialize)]
+#[derive(Clone, Copy, PartialEq, Eq, Debug, BorshSerialize, BorshDeserialize)]
 pub struct SubstrateContext {
   pub serai_time: u64,
   pub network_latest_finalized_block: BlockHash,
@@ -22,20 +20,10 @@ pub mod key_gen {
   use super::*;
 
   #[derive(
-    Clone,
-    Copy,
-    PartialEq,
-    Eq,
-    Hash,
-    Debug,
-    Zeroize,
-    Encode,
-    Decode,
-    BorshSerialize,
-    BorshDeserialize,
+    Clone, Copy, PartialEq, Eq, Hash, Debug, Encode, Decode, BorshSerialize, BorshDeserialize,
   )]
   pub struct KeyGenId {
-    pub set: ValidatorSet,
+    pub session: Session,
     pub attempt: u32,
   }
 
@@ -116,11 +104,9 @@ pub mod key_gen {
 pub mod sign {
   use super::*;
 
-  #[derive(
-    Clone, PartialEq, Eq, Hash, Debug, Zeroize, Encode, Decode, BorshSerialize, BorshDeserialize,
-  )]
+  #[derive(Clone, PartialEq, Eq, Hash, Debug, Encode, Decode, BorshSerialize, BorshDeserialize)]
   pub struct SignId {
-    pub key: Vec<u8>,
+    pub session: Session,
     pub id: [u8; 32],
     pub attempt: u32,
   }
@@ -134,7 +120,7 @@ pub mod sign {
     // Re-attempt a signing protocol.
     Reattempt { id: SignId },
     // Completed a signing protocol already.
-    Completed { key: Vec<u8>, id: [u8; 32], tx: Vec<u8> },
+    Completed { session: Session, id: [u8; 32], tx: Vec<u8> },
   }
 
   impl CoordinatorMessage {
@@ -142,17 +128,17 @@ pub mod sign {
       None
     }
 
-    pub fn key(&self) -> &[u8] {
+    pub fn session(&self) -> Session {
       match self {
-        CoordinatorMessage::Preprocesses { id, .. } => &id.key,
-        CoordinatorMessage::Shares { id, .. } => &id.key,
-        CoordinatorMessage::Reattempt { id } => &id.key,
-        CoordinatorMessage::Completed { key, .. } => key,
+        CoordinatorMessage::Preprocesses { id, .. } => id.session,
+        CoordinatorMessage::Shares { id, .. } => id.session,
+        CoordinatorMessage::Reattempt { id } => id.session,
+        CoordinatorMessage::Completed { session, .. } => *session,
       }
     }
   }
 
-  #[derive(Clone, PartialEq, Eq, Debug, Zeroize, BorshSerialize, BorshDeserialize)]
+  #[derive(Clone, PartialEq, Eq, Debug, BorshSerialize, BorshDeserialize)]
   pub enum ProcessorMessage {
     // Participant sent an invalid message during the sign protocol.
     InvalidParticipant { id: SignId, participant: Participant },
@@ -161,7 +147,7 @@ pub mod sign {
     // Signed share for the specified signing protocol.
     Share { id: SignId, shares: Vec<Vec<u8>> },
     // Completed a signing protocol already.
-    Completed { key: Vec<u8>, id: [u8; 32], tx: Vec<u8> },
+    Completed { session: Session, id: [u8; 32], tx: Vec<u8> },
   }
 }
 
@@ -178,28 +164,16 @@ pub mod coordinator {
   }
 
   #[derive(
-    Clone,
-    Copy,
-    PartialEq,
-    Eq,
-    Hash,
-    Debug,
-    Zeroize,
-    Encode,
-    Decode,
-    BorshSerialize,
-    BorshDeserialize,
+    Clone, Copy, PartialEq, Eq, Hash, Debug, Encode, Decode, BorshSerialize, BorshDeserialize,
   )]
   pub enum SubstrateSignableId {
     CosigningSubstrateBlock([u8; 32]),
     Batch([u8; 5]),
   }
 
-  #[derive(
-    Clone, PartialEq, Eq, Hash, Debug, Zeroize, Encode, Decode, BorshSerialize, BorshDeserialize,
-  )]
+  #[derive(Clone, PartialEq, Eq, Hash, Debug, Encode, Decode, BorshSerialize, BorshDeserialize)]
   pub struct SubstrateSignId {
-    pub key: [u8; 32],
+    pub session: Session,
     pub id: SubstrateSignableId,
     pub attempt: u32,
   }
@@ -226,26 +200,17 @@ pub mod coordinator {
         CoordinatorMessage::BatchReattempt { .. } => None,
       }
     }
-
-    pub fn key(&self) -> &[u8] {
-      match self {
-        CoordinatorMessage::CosignSubstrateBlock { id, .. } => &id.key,
-        CoordinatorMessage::SubstratePreprocesses { id, .. } => &id.key,
-        CoordinatorMessage::SubstrateShares { id, .. } => &id.key,
-        CoordinatorMessage::BatchReattempt { id } => &id.key,
-      }
-    }
   }
 
-  #[derive(Clone, PartialEq, Eq, Debug, Zeroize, BorshSerialize, BorshDeserialize)]
+  #[derive(Clone, PartialEq, Eq, Debug, BorshSerialize, BorshDeserialize)]
   pub struct PlanMeta {
-    pub key: Vec<u8>,
+    pub session: Session,
     pub id: [u8; 32],
   }
 
-  #[derive(Clone, PartialEq, Eq, Debug, Zeroize, BorshSerialize, BorshDeserialize)]
+  #[derive(Clone, PartialEq, Eq, Debug, BorshSerialize, BorshDeserialize)]
   pub enum ProcessorMessage {
-    SubstrateBlockAck { network: NetworkId, block: u64, plans: Vec<PlanMeta> },
+    SubstrateBlockAck { block: u64, plans: Vec<PlanMeta> },
     InvalidParticipant { id: SubstrateSignId, participant: Participant },
     CosignPreprocess { id: SubstrateSignId, preprocesses: Vec<[u8; 64]> },
     BatchPreprocess { id: SubstrateSignId, block: BlockHash, preprocesses: Vec<[u8; 64]> },
@@ -261,12 +226,11 @@ pub mod substrate {
   pub enum CoordinatorMessage {
     ConfirmKeyPair {
       context: SubstrateContext,
-      set: ValidatorSet,
+      session: Session,
       key_pair: KeyPair,
     },
     SubstrateBlock {
       context: SubstrateContext,
-      network: NetworkId,
       block: u64,
       burns: Vec<OutInstructionWithBalance>,
       batches: Vec<u32>,
@@ -283,7 +247,7 @@ pub mod substrate {
     }
   }
 
-  #[derive(Clone, PartialEq, Eq, Debug, Zeroize, BorshSerialize, BorshDeserialize)]
+  #[derive(Clone, PartialEq, Eq, Debug, BorshSerialize, BorshDeserialize)]
   pub enum ProcessorMessage {
     Batch { batch: Batch },
     SignedBatch { batch: SignedBatch },
@@ -364,7 +328,7 @@ impl CoordinatorMessage {
   pub fn intent(&self) -> Vec<u8> {
     match self {
       CoordinatorMessage::KeyGen(msg) => {
-        // Unique since key gen ID embeds the validator set and attempt
+        // Unique since key gen ID embeds the session and attempt
         let (sub, id) = match msg {
           key_gen::CoordinatorMessage::GenerateKey { id, .. } => (0, id),
           key_gen::CoordinatorMessage::Commitments { id, .. } => (1, id),
@@ -409,11 +373,9 @@ impl CoordinatorMessage {
       }
       CoordinatorMessage::Substrate(msg) => {
         let (sub, id) = match msg {
-          // Unique since there's only one key pair for a set
-          substrate::CoordinatorMessage::ConfirmKeyPair { set, .. } => (0, set.encode()),
-          substrate::CoordinatorMessage::SubstrateBlock { network, block, .. } => {
-            (1, (network, block).encode())
-          }
+          // Unique since there's only one key pair for a session
+          substrate::CoordinatorMessage::ConfirmKeyPair { session, .. } => (0, session.encode()),
+          substrate::CoordinatorMessage::SubstrateBlock { block, .. } => (1, block.encode()),
         };
 
         let mut res = vec![COORDINATOR_UID, TYPE_SUBSTRATE_UID, sub];
@@ -464,9 +426,7 @@ impl ProcessorMessage {
       }
       ProcessorMessage::Coordinator(msg) => {
         let (sub, id) = match msg {
-          coordinator::ProcessorMessage::SubstrateBlockAck { network, block, .. } => {
-            (0, (network, block).encode())
-          }
+          coordinator::ProcessorMessage::SubstrateBlockAck { block, .. } => (0, block.encode()),
           // Unique since SubstrateSignId
           coordinator::ProcessorMessage::InvalidParticipant { id, .. } => (1, id.encode()),
           coordinator::ProcessorMessage::CosignPreprocess { id, .. } => (2, id.encode()),
diff --git a/processor/src/batch_signer.rs b/processor/src/batch_signer.rs
index b77008561..9b8cb995a 100644
--- a/processor/src/batch_signer.rs
+++ b/processor/src/batch_signer.rs
@@ -3,7 +3,6 @@ use std::collections::HashMap;
 
 use rand_core::OsRng;
 
-use ciphersuite::group::GroupEncoding;
 use frost::{
   curve::Ristretto,
   ThresholdKeys, FrostError,
@@ -21,6 +20,7 @@ use scale::Encode;
 use serai_client::{
   primitives::{NetworkId, BlockHash},
   in_instructions::primitives::{Batch, SignedBatch, batch_message},
+  validator_sets::primitives::Session,
 };
 
 use messages::coordinator::*;
@@ -48,6 +48,7 @@ pub struct BatchSigner<D: Db> {
   db: PhantomData<D>,
 
   network: NetworkId,
+  session: Session,
   keys: Vec<ThresholdKeys<Ristretto>>,
 
   signable: HashMap<[u8; 5], Batch>,
@@ -71,12 +72,17 @@ impl<D: Db> fmt::Debug for BatchSigner<D> {
 }
 
 impl<D: Db> BatchSigner<D> {
-  pub fn new(network: NetworkId, keys: Vec<ThresholdKeys<Ristretto>>) -> BatchSigner<D> {
+  pub fn new(
+    network: NetworkId,
+    session: Session,
+    keys: Vec<ThresholdKeys<Ristretto>>,
+  ) -> BatchSigner<D> {
     assert!(!keys.is_empty());
     BatchSigner {
       db: PhantomData,
 
       network,
+      session,
       keys,
 
       signable: HashMap::new(),
@@ -86,11 +92,11 @@ impl<D: Db> BatchSigner<D> {
     }
   }
 
-  fn verify_id(&self, id: &SubstrateSignId) -> Result<([u8; 32], [u8; 5], u32), ()> {
-    let SubstrateSignId { key, id, attempt } = id;
+  fn verify_id(&self, id: &SubstrateSignId) -> Result<(Session, [u8; 5], u32), ()> {
+    let SubstrateSignId { session, id, attempt } = id;
     let SubstrateSignableId::Batch(id) = id else { panic!("BatchSigner handed non-Batch") };
 
-    assert_eq!(key, &self.keys[0].group_key().to_bytes());
+    assert_eq!(session, &self.session);
 
     // Check the attempt lines up
     match self.attempt.get(id) {
@@ -114,7 +120,7 @@ impl<D: Db> BatchSigner<D> {
       }
     }
 
-    Ok((*key, *id, *attempt))
+    Ok((*session, *id, *attempt))
   }
 
   #[must_use]
@@ -196,11 +202,7 @@ impl<D: Db> BatchSigner<D> {
     }
     self.preprocessing.insert(id, (machines, preprocesses));
 
-    let id = SubstrateSignId {
-      key: self.keys[0].group_key().to_bytes(),
-      id: SubstrateSignableId::Batch(id),
-      attempt,
-    };
+    let id = SubstrateSignId { session: self.session, id: SubstrateSignableId::Batch(id), attempt };
 
     // Broadcast our preprocesses
     Some(ProcessorMessage::BatchPreprocess { id, block, preprocesses: serialized_preprocesses })
@@ -236,10 +238,10 @@ impl<D: Db> BatchSigner<D> {
       }
 
       CoordinatorMessage::SubstratePreprocesses { id, preprocesses } => {
-        let (key, id, attempt) = self.verify_id(&id).ok()?;
+        let (session, id, attempt) = self.verify_id(&id).ok()?;
 
         let substrate_sign_id =
-          SubstrateSignId { key, id: SubstrateSignableId::Batch(id), attempt };
+          SubstrateSignId { session, id: SubstrateSignableId::Batch(id), attempt };
 
         let (machines, our_preprocesses) = match self.preprocessing.remove(&id) {
           // Either rebooted or RPC error, or some invariant
@@ -328,10 +330,10 @@ impl<D: Db> BatchSigner<D> {
       }
 
       CoordinatorMessage::SubstrateShares { id, shares } => {
-        let (key, id, attempt) = self.verify_id(&id).ok()?;
+        let (session, id, attempt) = self.verify_id(&id).ok()?;
 
         let substrate_sign_id =
-          SubstrateSignId { key, id: SubstrateSignableId::Batch(id), attempt };
+          SubstrateSignId { session, id: SubstrateSignableId::Batch(id), attempt };
 
         let (machine, our_shares) = match self.signing.remove(&id) {
           // Rebooted, RPC error, or some invariant
diff --git a/processor/src/cosigner.rs b/processor/src/cosigner.rs
index c53772cfe..551a14c50 100644
--- a/processor/src/cosigner.rs
+++ b/processor/src/cosigner.rs
@@ -3,7 +3,6 @@ use std::collections::HashMap;
 
 use rand_core::OsRng;
 
-use ciphersuite::group::GroupEncoding;
 use frost::{
   curve::Ristretto,
   ThresholdKeys, FrostError,
@@ -18,6 +17,7 @@ use frost_schnorrkel::Schnorrkel;
 use log::{info, warn};
 
 use scale::Encode;
+use serai_client::validator_sets::primitives::Session;
 
 use messages::coordinator::*;
 use crate::{Get, DbTxn, create_db};
@@ -35,7 +35,7 @@ type SignatureShare = <AlgorithmSignMachine<Ristretto, Schnorrkel> as SignMachin
 >>::SignatureShare;
 
 pub struct Cosigner {
-  #[allow(dead_code)] // False positive
+  session: Session,
   keys: Vec<ThresholdKeys<Ristretto>>,
 
   block_number: u64,
@@ -51,6 +51,7 @@ impl fmt::Debug for Cosigner {
   fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
     fmt
       .debug_struct("Cosigner")
+      .field("session", &self.session)
       .field("block_number", &self.block_number)
       .field("id", &self.id)
       .field("attempt", &self.attempt)
@@ -63,6 +64,7 @@ impl fmt::Debug for Cosigner {
 impl Cosigner {
   pub fn new(
     txn: &mut impl DbTxn,
+    session: Session,
     keys: Vec<ThresholdKeys<Ristretto>>,
     block_number: u64,
     id: [u8; 32],
@@ -100,14 +102,11 @@ impl Cosigner {
     }
     let preprocessing = Some((machines, preprocesses));
 
-    let substrate_sign_id = SubstrateSignId {
-      key: keys[0].group_key().to_bytes(),
-      id: SubstrateSignableId::CosigningSubstrateBlock(id),
-      attempt,
-    };
+    let substrate_sign_id =
+      SubstrateSignId { session, id: SubstrateSignableId::CosigningSubstrateBlock(id), attempt };
 
     Some((
-      Cosigner { keys, block_number, id, attempt, preprocessing, signing: None },
+      Cosigner { session, keys, block_number, id, attempt, preprocessing, signing: None },
       ProcessorMessage::CosignPreprocess {
         id: substrate_sign_id,
         preprocesses: serialized_preprocesses,
@@ -127,7 +126,7 @@ impl Cosigner {
       }
 
       CoordinatorMessage::SubstratePreprocesses { id, preprocesses } => {
-        assert_eq!(id.key, self.keys[0].group_key().to_bytes());
+        assert_eq!(id.session, self.session);
         let SubstrateSignableId::CosigningSubstrateBlock(block) = id.id else {
           panic!("cosigner passed Batch")
         };
@@ -212,7 +211,7 @@ impl Cosigner {
       }
 
       CoordinatorMessage::SubstrateShares { id, shares } => {
-        assert_eq!(id.key, self.keys[0].group_key().to_bytes());
+        assert_eq!(id.session, self.session);
         let SubstrateSignableId::CosigningSubstrateBlock(block) = id.id else {
           panic!("cosigner passed Batch")
         };
diff --git a/processor/src/db.rs b/processor/src/db.rs
index d2d4da427..e02051d8e 100644
--- a/processor/src/db.rs
+++ b/processor/src/db.rs
@@ -1,7 +1,7 @@
 use std::io::Read;
 
 use scale::{Encode, Decode};
-use serai_client::validator_sets::primitives::{ValidatorSet, KeyPair};
+use serai_client::validator_sets::primitives::{Session, KeyPair};
 
 pub use serai_db::*;
 
@@ -17,15 +17,15 @@ create_db!(
 impl PendingActivationsDb {
   pub fn pending_activation<N: Network>(
     getter: &impl Get,
-  ) -> Option<(<N::Block as Block<N>>::Id, ValidatorSet, KeyPair)> {
+  ) -> Option<(<N::Block as Block<N>>::Id, Session, KeyPair)> {
     if let Some(bytes) = Self::get(getter) {
       if !bytes.is_empty() {
         let mut slice = bytes.as_slice();
-        let (set, key_pair) = <(ValidatorSet, KeyPair)>::decode(&mut slice).unwrap();
+        let (session, key_pair) = <(Session, KeyPair)>::decode(&mut slice).unwrap();
         let mut block_before_queue_block = <N::Block as Block<N>>::Id::default();
         slice.read_exact(block_before_queue_block.as_mut()).unwrap();
         assert!(slice.is_empty());
-        return Some((block_before_queue_block, set, key_pair));
+        return Some((block_before_queue_block, session, key_pair));
       }
     }
     None
@@ -33,10 +33,10 @@ impl PendingActivationsDb {
   pub fn set_pending_activation<N: Network>(
     txn: &mut impl DbTxn,
     block_before_queue_block: <N::Block as Block<N>>::Id,
-    set: ValidatorSet,
+    session: Session,
     key_pair: KeyPair,
   ) {
-    let mut buf = (set, key_pair).encode();
+    let mut buf = (session, key_pair).encode();
     buf.extend(block_before_queue_block.as_ref());
     Self::set(txn, &buf);
   }
diff --git a/processor/src/key_gen.rs b/processor/src/key_gen.rs
index 54762b875..9cd6657f3 100644
--- a/processor/src/key_gen.rs
+++ b/processor/src/key_gen.rs
@@ -17,7 +17,7 @@ use frost::{
 use log::info;
 
 use scale::Encode;
-use serai_client::validator_sets::primitives::{ValidatorSet, KeyPair};
+use serai_client::validator_sets::primitives::{Session, KeyPair};
 use messages::key_gen::*;
 
 use crate::{Get, DbTxn, Db, create_db, networks::Network};
@@ -30,16 +30,17 @@ pub struct KeyConfirmed<C: Ciphersuite> {
 
 create_db!(
   KeyGenDb {
-    ParamsDb: (set: &ValidatorSet) -> (ThresholdParams, u16),
+    ParamsDb: (session: &Session) -> (ThresholdParams, u16),
     // Not scoped to the set since that'd have latter attempts overwrite former
     // A former attempt may become the finalized attempt, even if it doesn't in a timely manner
     // Overwriting its commitments would be accordingly poor
     CommitmentsDb: (key: &KeyGenId) -> HashMap<Participant, Vec<u8>>,
-    GeneratedKeysDb: (set: &ValidatorSet, substrate_key: &[u8; 32], network_key: &[u8]) -> Vec<u8>,
+    GeneratedKeysDb: (session: &Session, substrate_key: &[u8; 32], network_key: &[u8]) -> Vec<u8>,
     // These do assume a key is only used once across sets, which holds true so long as a single
     // participant is honest in their execution of the protocol
     KeysDb: (network_key: &[u8]) -> Vec<u8>,
-    NetworkKey: (substrate_key: [u8; 32]) -> Vec<u8>,
+    SessionDb: (network_key: &[u8]) -> Session,
+    NetworkKeyDb: (session: Session) -> Vec<u8>,
   }
 );
 
@@ -76,7 +77,7 @@ impl GeneratedKeysDb {
     }
     txn.put(
       Self::key(
-        &id.set,
+        &id.session,
         &substrate_keys[0].group_key().to_bytes(),
         network_keys[0].group_key().to_bytes().as_ref(),
       ),
@@ -88,12 +89,12 @@ impl GeneratedKeysDb {
 impl KeysDb {
   fn confirm_keys<N: Network>(
     txn: &mut impl DbTxn,
-    set: ValidatorSet,
+    session: Session,
     key_pair: KeyPair,
   ) -> (Vec<ThresholdKeys<Ristretto>>, Vec<ThresholdKeys<N::Curve>>) {
     let (keys_vec, keys) = GeneratedKeysDb::read_keys::<N>(
       txn,
-      &GeneratedKeysDb::key(&set, &key_pair.0 .0, key_pair.1.as_ref()),
+      &GeneratedKeysDb::key(&session, &key_pair.0 .0, key_pair.1.as_ref()),
     )
     .unwrap();
     assert_eq!(key_pair.0 .0, keys.0[0].group_key().to_bytes());
@@ -104,8 +105,9 @@ impl KeysDb {
       },
       keys.1[0].group_key().to_bytes().as_ref(),
     );
-    txn.put(KeysDb::key(keys.1[0].group_key().to_bytes().as_ref()), keys_vec);
-    NetworkKey::set(txn, key_pair.0.into(), &key_pair.1.clone().into_inner());
+    txn.put(Self::key(key_pair.1.as_ref()), keys_vec);
+    NetworkKeyDb::set(txn, session, &key_pair.1.clone().into_inner());
+    SessionDb::set(txn, key_pair.1.as_ref(), &session);
     keys
   }
 
@@ -113,21 +115,19 @@ impl KeysDb {
   fn keys<N: Network>(
     getter: &impl Get,
     network_key: &<N::Curve as Ciphersuite>::G,
-  ) -> Option<(Vec<ThresholdKeys<Ristretto>>, Vec<ThresholdKeys<N::Curve>>)> {
+  ) -> Option<(Session, (Vec<ThresholdKeys<Ristretto>>, Vec<ThresholdKeys<N::Curve>>))> {
     let res =
       GeneratedKeysDb::read_keys::<N>(getter, &Self::key(network_key.to_bytes().as_ref()))?.1;
     assert_eq!(&res.1[0].group_key(), network_key);
-    Some(res)
+    Some((SessionDb::get(getter, network_key.to_bytes().as_ref()).unwrap(), res))
   }
 
-  pub fn substrate_keys_by_substrate_key<N: Network>(
+  pub fn substrate_keys_by_session<N: Network>(
     getter: &impl Get,
-    substrate_key: &[u8; 32],
+    session: Session,
   ) -> Option<Vec<ThresholdKeys<Ristretto>>> {
-    let network_key = NetworkKey::get(getter, *substrate_key)?;
-    let res = GeneratedKeysDb::read_keys::<N>(getter, &Self::key(&network_key))?.1;
-    assert_eq!(&res.0[0].group_key().to_bytes(), substrate_key);
-    Some(res.0)
+    let network_key = NetworkKeyDb::get(getter, session)?;
+    Some(GeneratedKeysDb::read_keys::<N>(getter, &Self::key(&network_key))?.1 .0)
   }
 }
 
@@ -140,9 +140,9 @@ pub struct KeyGen<N: Network, D: Db> {
   db: D,
   entropy: Zeroizing<[u8; 32]>,
 
-  active_commit: HashMap<ValidatorSet, (SecretShareMachines<N>, Vec<Vec<u8>>)>,
+  active_commit: HashMap<Session, (SecretShareMachines<N>, Vec<Vec<u8>>)>,
   #[allow(clippy::type_complexity)]
-  active_share: HashMap<ValidatorSet, (KeyMachines<N>, Vec<HashMap<Participant, Vec<u8>>>)>,
+  active_share: HashMap<Session, (KeyMachines<N>, Vec<HashMap<Participant, Vec<u8>>>)>,
 }
 
 impl<N: Network, D: Db> KeyGen<N, D> {
@@ -151,26 +151,26 @@ impl<N: Network, D: Db> KeyGen<N, D> {
     KeyGen { db, entropy, active_commit: HashMap::new(), active_share: HashMap::new() }
   }
 
-  pub fn in_set(&self, set: &ValidatorSet) -> bool {
-    // We determine if we're in set using if we have the parameters for a set's key generation
-    ParamsDb::get(&self.db, set).is_some()
+  pub fn in_set(&self, session: &Session) -> bool {
+    // We determine if we're in set using if we have the parameters for a session's key generation
+    ParamsDb::get(&self.db, session).is_some()
   }
 
   #[allow(clippy::type_complexity)]
   pub fn keys(
     &self,
     key: &<N::Curve as Ciphersuite>::G,
-  ) -> Option<(Vec<ThresholdKeys<Ristretto>>, Vec<ThresholdKeys<N::Curve>>)> {
+  ) -> Option<(Session, (Vec<ThresholdKeys<Ristretto>>, Vec<ThresholdKeys<N::Curve>>))> {
     // This is safe, despite not having a txn, since it's a static value
     // It doesn't change over time/in relation to other operations
     KeysDb::keys::<N>(&self.db, key)
   }
 
-  pub fn substrate_keys_by_substrate_key(
+  pub fn substrate_keys_by_session(
     &self,
-    substrate_key: &[u8; 32],
+    session: Session,
   ) -> Option<Vec<ThresholdKeys<Ristretto>>> {
-    KeysDb::substrate_keys_by_substrate_key::<N>(&self.db, substrate_key)
+    KeysDb::substrate_keys_by_session::<N>(&self.db, session)
   }
 
   pub async fn handle(
@@ -184,7 +184,10 @@ impl<N: Network, D: Db> KeyGen<N, D> {
       // TODO2: Also embed the chain ID/genesis block
       format!(
         "Serai Key Gen. Session: {:?}, Network: {:?}, Attempt: {}, Key: {}",
-        id.set.session, id.set.network, id.attempt, key,
+        id.session,
+        N::NETWORK,
+        id.attempt,
+        key,
       )
     };
 
@@ -313,15 +316,15 @@ impl<N: Network, D: Db> KeyGen<N, D> {
         info!("Generating new key. ID: {id:?} Params: {params:?} Shares: {shares}");
 
         // Remove old attempts
-        if self.active_commit.remove(&id.set).is_none() &&
-          self.active_share.remove(&id.set).is_none()
+        if self.active_commit.remove(&id.session).is_none() &&
+          self.active_share.remove(&id.session).is_none()
         {
-          // If we haven't handled this set before, save the params
-          ParamsDb::set(txn, &id.set, &(params, shares));
+          // If we haven't handled this session before, save the params
+          ParamsDb::set(txn, &id.session, &(params, shares));
         }
 
         let (machines, commitments) = key_gen_machines(id, params, shares);
-        self.active_commit.insert(id.set, (machines, commitments.clone()));
+        self.active_commit.insert(id.session, (machines, commitments.clone()));
 
         ProcessorMessage::Commitments { id, commitments }
       }
@@ -329,14 +332,14 @@ impl<N: Network, D: Db> KeyGen<N, D> {
       CoordinatorMessage::Commitments { id, mut commitments } => {
         info!("Received commitments for {:?}", id);
 
-        if self.active_share.contains_key(&id.set) {
+        if self.active_share.contains_key(&id.session) {
           // We should've been told of a new attempt before receiving commitments again
           // The coordinator is either missing messages or repeating itself
           // Either way, it's faulty
           panic!("commitments when already handled commitments");
         }
 
-        let (params, share_quantity) = ParamsDb::get(txn, &id.set).unwrap();
+        let (params, share_quantity) = ParamsDb::get(txn, &id.session).unwrap();
 
         // Unwrap the machines, rebuilding them if we didn't have them in our cache
         // We won't if the processor rebooted
@@ -345,7 +348,7 @@ impl<N: Network, D: Db> KeyGen<N, D> {
         // The coordinator is trusted to be proper in this regard
         let (prior, our_commitments) = self
           .active_commit
-          .remove(&id.set)
+          .remove(&id.session)
           .unwrap_or_else(|| key_gen_machines(id, params, share_quantity));
 
         for (i, our_commitments) in our_commitments.into_iter().enumerate() {
@@ -361,7 +364,7 @@ impl<N: Network, D: Db> KeyGen<N, D> {
 
         match secret_share_machines(id, params, prior, commitments) {
           Ok((machines, shares)) => {
-            self.active_share.insert(id.set, (machines, shares.clone()));
+            self.active_share.insert(id.session, (machines, shares.clone()));
             ProcessorMessage::Shares { id, shares }
           }
           Err(e) => e,
@@ -371,10 +374,10 @@ impl<N: Network, D: Db> KeyGen<N, D> {
       CoordinatorMessage::Shares { id, shares } => {
         info!("Received shares for {:?}", id);
 
-        let (params, share_quantity) = ParamsDb::get(txn, &id.set).unwrap();
+        let (params, share_quantity) = ParamsDb::get(txn, &id.session).unwrap();
 
         // Same commentary on inconsistency as above exists
-        let (machines, our_shares) = self.active_share.remove(&id.set).unwrap_or_else(|| {
+        let (machines, our_shares) = self.active_share.remove(&id.session).unwrap_or_else(|| {
           let prior = key_gen_machines(id, params, share_quantity).0;
           let (machines, shares) =
             secret_share_machines(id, params, prior, CommitmentsDb::get(txn, &id).unwrap())
@@ -512,7 +515,7 @@ impl<N: Network, D: Db> KeyGen<N, D> {
       }
 
       CoordinatorMessage::VerifyBlame { id, accuser, accused, share, blame } => {
-        let params = ParamsDb::get(txn, &id.set).unwrap().0;
+        let params = ParamsDb::get(txn, &id.session).unwrap().0;
 
         let mut share_ref = share.as_slice();
         let Ok(substrate_share) = EncryptedMessage::<
@@ -580,17 +583,17 @@ impl<N: Network, D: Db> KeyGen<N, D> {
   pub async fn confirm(
     &mut self,
     txn: &mut D::Transaction<'_>,
-    set: ValidatorSet,
+    session: Session,
     key_pair: KeyPair,
   ) -> KeyConfirmed<N::Curve> {
     info!(
-      "Confirmed key pair {} {} for set {:?}",
+      "Confirmed key pair {} {} for {:?}",
       hex::encode(key_pair.0),
       hex::encode(&key_pair.1),
-      set,
+      session,
     );
 
-    let (substrate_keys, network_keys) = KeysDb::confirm_keys::<N>(txn, set, key_pair);
+    let (substrate_keys, network_keys) = KeysDb::confirm_keys::<N>(txn, session, key_pair);
 
     KeyConfirmed { substrate_keys, network_keys }
   }
diff --git a/processor/src/main.rs b/processor/src/main.rs
index 238297040..799e528f6 100644
--- a/processor/src/main.rs
+++ b/processor/src/main.rs
@@ -10,7 +10,7 @@ use tokio::time::sleep;
 
 use serai_client::{
   primitives::{BlockHash, NetworkId},
-  validator_sets::primitives::{ValidatorSet, KeyPair},
+  validator_sets::primitives::{Session, KeyPair},
 };
 
 use messages::{
@@ -44,7 +44,7 @@ mod coordinator;
 pub use coordinator::*;
 
 mod key_gen;
-use key_gen::{KeyConfirmed, KeyGen};
+use key_gen::{SessionDb, KeyConfirmed, KeyGen};
 
 mod signer;
 use signer::Signer;
@@ -84,7 +84,7 @@ struct TributaryMutable<N: Network, D: Db> {
   // invalidating the Tributary's mutable borrow. The signer is coded to allow for attempted usage
   // of a dropped task.
   key_gen: KeyGen<N, D>,
-  signers: HashMap<Vec<u8>, Signer<N, D>>,
+  signers: HashMap<Session, Signer<N, D>>,
 
   // This is also mutably borrowed by the Scanner.
   // The Scanner starts new sign tasks.
@@ -187,25 +187,26 @@ async fn handle_coordinator_msg<D: Db, N: Network, Co: Coordinator>(
     substrate_mutable: &mut SubstrateMutable<N, D>,
     tributary_mutable: &mut TributaryMutable<N, D>,
     txn: &mut D::Transaction<'_>,
-    set: ValidatorSet,
+    session: Session,
     key_pair: KeyPair,
     activation_number: usize,
   ) {
-    info!("activating {set:?}'s keys at {activation_number}");
+    info!("activating {session:?}'s keys at {activation_number}");
 
     let network_key = <N as Network>::Curve::read_G::<&[u8]>(&mut key_pair.1.as_ref())
       .expect("Substrate finalized invalid point as a network's key");
 
-    if tributary_mutable.key_gen.in_set(&set) {
+    if tributary_mutable.key_gen.in_set(&session) {
       // See TributaryMutable's struct definition for why this block is safe
       let KeyConfirmed { substrate_keys, network_keys } =
-        tributary_mutable.key_gen.confirm(txn, set, key_pair.clone()).await;
-      if set.session.0 == 0 {
-        tributary_mutable.batch_signer = Some(BatchSigner::new(N::NETWORK, substrate_keys));
+        tributary_mutable.key_gen.confirm(txn, session, key_pair.clone()).await;
+      if session.0 == 0 {
+        tributary_mutable.batch_signer =
+          Some(BatchSigner::new(N::NETWORK, session, substrate_keys));
       }
       tributary_mutable
         .signers
-        .insert(key_pair.1.into(), Signer::new(network.clone(), network_keys));
+        .insert(session, Signer::new(network.clone(), session, network_keys));
     }
 
     substrate_mutable.add_key(txn, activation_number, network_key).await;
@@ -219,7 +220,7 @@ async fn handle_coordinator_msg<D: Db, N: Network, Co: Coordinator>(
     CoordinatorMessage::Sign(msg) => {
       if let Some(msg) = tributary_mutable
         .signers
-        .get_mut(msg.key())
+        .get_mut(&msg.session())
         .expect("coordinator told us to sign with a signer we don't have")
         .handle(txn, msg)
         .await
@@ -257,11 +258,11 @@ async fn handle_coordinator_msg<D: Db, N: Network, Co: Coordinator>(
             let SubstrateSignableId::CosigningSubstrateBlock(block) = id.id else {
               panic!("CosignSubstrateBlock id didn't have a CosigningSubstrateBlock")
             };
-            let Some(keys) = tributary_mutable.key_gen.substrate_keys_by_substrate_key(&id.key)
-            else {
+            let Some(keys) = tributary_mutable.key_gen.substrate_keys_by_session(id.session) else {
               panic!("didn't have key shares for the key we were told to cosign with");
             };
-            if let Some((cosigner, msg)) = Cosigner::new(txn, keys, block_number, block, id.attempt)
+            if let Some((cosigner, msg)) =
+              Cosigner::new(txn, id.session, keys, block_number, block, id.attempt)
             {
               tributary_mutable.cosigner = Some(cosigner);
               coordinator.send(msg).await;
@@ -287,7 +288,7 @@ async fn handle_coordinator_msg<D: Db, N: Network, Co: Coordinator>(
 
     CoordinatorMessage::Substrate(msg) => {
       match msg {
-        messages::substrate::CoordinatorMessage::ConfirmKeyPair { context, set, key_pair } => {
+        messages::substrate::CoordinatorMessage::ConfirmKeyPair { context, session, key_pair } => {
           // This is the first key pair for this network so no block has been finalized yet
           // TODO: Write documentation for this in docs/
           // TODO: Use an Option instead of a magic?
@@ -339,7 +340,7 @@ async fn handle_coordinator_msg<D: Db, N: Network, Co: Coordinator>(
               substrate_mutable,
               tributary_mutable,
               txn,
-              set,
+              session,
               key_pair,
               activation_number,
             )
@@ -355,7 +356,7 @@ async fn handle_coordinator_msg<D: Db, N: Network, Co: Coordinator>(
             PendingActivationsDb::set_pending_activation::<N>(
               txn,
               block_before_queue_block,
-              set,
+              session,
               key_pair,
             );
           }
@@ -363,14 +364,13 @@ async fn handle_coordinator_msg<D: Db, N: Network, Co: Coordinator>(
 
         messages::substrate::CoordinatorMessage::SubstrateBlock {
           context,
-          network: network_id,
           block: substrate_block,
           burns,
           batches,
         } => {
-          assert_eq!(network_id, N::NETWORK, "coordinator sent us data for another network");
-
-          if let Some((block, set, key_pair)) = PendingActivationsDb::pending_activation::<N>(txn) {
+          if let Some((block, session, key_pair)) =
+            PendingActivationsDb::pending_activation::<N>(txn)
+          {
             // Only run if this is a Batch belonging to a distinct block
             if context.network_latest_finalized_block.as_ref() != block.as_ref() {
               let mut queue_block = <N::Block as Block<N>>::Id::default();
@@ -387,7 +387,7 @@ async fn handle_coordinator_msg<D: Db, N: Network, Co: Coordinator>(
                 substrate_mutable,
                 tributary_mutable,
                 txn,
-                set,
+                session,
                 key_pair,
                 activation_number,
               )
@@ -412,13 +412,12 @@ async fn handle_coordinator_msg<D: Db, N: Network, Co: Coordinator>(
           if !tributary_mutable.signers.is_empty() {
             coordinator
               .send(messages::coordinator::ProcessorMessage::SubstrateBlockAck {
-                network: N::NETWORK,
                 block: substrate_block,
                 plans: to_sign
                   .iter()
-                  .map(|signable| PlanMeta {
-                    key: signable.0.to_bytes().as_ref().to_vec(),
-                    id: signable.1,
+                  .filter_map(|signable| {
+                    SessionDb::get(txn, signable.0.to_bytes().as_ref())
+                      .map(|session| PlanMeta { session, id: signable.1 })
                   })
                   .collect(),
               })
@@ -428,7 +427,8 @@ async fn handle_coordinator_msg<D: Db, N: Network, Co: Coordinator>(
           // See commentary in TributaryMutable for why this is safe
           let signers = &mut tributary_mutable.signers;
           for (key, id, tx, eventuality) in to_sign {
-            if let Some(signer) = signers.get_mut(key.to_bytes().as_ref()) {
+            if let Some(session) = SessionDb::get(txn, key.to_bytes().as_ref()) {
+              let signer = signers.get_mut(&session).unwrap();
               if let Some(msg) = signer.sign_transaction(txn, id, tx, eventuality).await {
                 coordinator.send(msg).await;
               }
@@ -494,7 +494,7 @@ async fn boot<N: Network, D: Db, Co: Coordinator>(
   let mut signers = HashMap::new();
 
   for (i, key) in current_keys.iter().enumerate() {
-    let Some((substrate_keys, network_keys)) = key_gen.keys(key) else { continue };
+    let Some((session, (substrate_keys, network_keys))) = key_gen.keys(key) else { continue };
     let network_key = network_keys[0].group_key();
 
     // If this is the oldest key, load the BatchSigner for it as the active BatchSigner
@@ -503,7 +503,7 @@ async fn boot<N: Network, D: Db, Co: Coordinator>(
     // We don't have to load any state for this since the Scanner will re-fire any events
     // necessary, only no longer scanning old blocks once Substrate acks them
     if i == 0 {
-      batch_signer = Some(BatchSigner::new(N::NETWORK, substrate_keys));
+      batch_signer = Some(BatchSigner::new(N::NETWORK, session, substrate_keys));
     }
 
     // The Scanner re-fires events as needed for batch_signer yet not signer
@@ -514,10 +514,9 @@ async fn boot<N: Network, D: Db, Co: Coordinator>(
     // 2) Cause re-emission of Batch events, which we'd need to check the safety of
     //    (TODO: Do anyways?)
     // 3) Violate the attempt counter (TODO: Is this already being violated?)
-    let mut signer = Signer::new(network.clone(), network_keys);
+    let mut signer = Signer::new(network.clone(), session, network_keys);
 
     // Sign any TXs being actively signed
-    let key = key.to_bytes();
     for (plan, tx, eventuality) in &actively_signing {
       if plan.key == network_key {
         let mut txn = raw_db.txn();
@@ -531,7 +530,7 @@ async fn boot<N: Network, D: Db, Co: Coordinator>(
       }
     }
 
-    signers.insert(key.as_ref().to_vec(), signer);
+    signers.insert(session, signer);
   }
 
   // Spawn a task to rebroadcast signed TXs yet to be mined into a finalized block
@@ -630,16 +629,20 @@ async fn run<N: Network, D: Db, Co: Coordinator>(mut raw_db: D, network: N, mut
 
             if let Some((retired_key, new_key)) = retired_key_new_key {
               // Safe to mutate since all signing operations are done and no more will be added
-              tributary_mutable.signers.remove(retired_key.to_bytes().as_ref());
+              if let Some(retired_session) = SessionDb::get(&txn, retired_key.to_bytes().as_ref()) {
+                tributary_mutable.signers.remove(&retired_session);
+              }
               tributary_mutable.batch_signer.take();
-              if let Some((substrate_keys, _)) = tributary_mutable.key_gen.keys(&new_key) {
+              let keys = tributary_mutable.key_gen.keys(&new_key);
+              if let Some((session, (substrate_keys, _))) = keys {
                 tributary_mutable.batch_signer =
-                  Some(BatchSigner::new(N::NETWORK, substrate_keys));
+                  Some(BatchSigner::new(N::NETWORK, session, substrate_keys));
               }
             }
           },
           MultisigEvent::Completed(key, id, tx) => {
-            if let Some(signer) = tributary_mutable.signers.get_mut(&key) {
+            if let Some(session) = SessionDb::get(&txn, &key) {
+              let signer = tributary_mutable.signers.get_mut(&session).unwrap();
               if let Some(msg) = signer.completed(&mut txn, id, tx) {
                 coordinator.send(msg).await;
               }
diff --git a/processor/src/signer.rs b/processor/src/signer.rs
index 80bc9857a..3fcb0d70b 100644
--- a/processor/src/signer.rs
+++ b/processor/src/signer.rs
@@ -11,6 +11,7 @@ use frost::{
 use log::{info, debug, warn, error};
 
 use scale::Encode;
+use serai_client::validator_sets::primitives::Session;
 use messages::sign::*;
 
 pub use serai_db::*;
@@ -131,6 +132,7 @@ pub struct Signer<N: Network, D: Db> {
 
   network: N,
 
+  session: Session,
   keys: Vec<ThresholdKeys<N::Curve>>,
 
   signable: HashMap<[u8; 32], N::SignableTransaction>,
@@ -172,13 +174,14 @@ impl<N: Network, D: Db> Signer<N, D> {
       tokio::time::sleep(core::time::Duration::from_secs(5 * 60)).await;
     }
   }
-  pub fn new(network: N, keys: Vec<ThresholdKeys<N::Curve>>) -> Signer<N, D> {
+  pub fn new(network: N, session: Session, keys: Vec<ThresholdKeys<N::Curve>>) -> Signer<N, D> {
     assert!(!keys.is_empty());
     Signer {
       db: PhantomData,
 
       network,
 
+      session,
       keys,
 
       signable: HashMap::new(),
@@ -250,11 +253,7 @@ impl<N: Network, D: Db> Signer<N, D> {
     self.signing.remove(&id);
 
     // Emit the event for it
-    ProcessorMessage::Completed {
-      key: self.keys[0].group_key().to_bytes().as_ref().to_vec(),
-      id,
-      tx: tx_id.as_ref().to_vec(),
-    }
+    ProcessorMessage::Completed { session: self.session, id, tx: tx_id.as_ref().to_vec() }
   }
 
   #[must_use]
@@ -371,7 +370,7 @@ impl<N: Network, D: Db> Signer<N, D> {
     // Update the attempt number
     self.attempt.insert(id, attempt);
 
-    let id = SignId { key: self.keys[0].group_key().to_bytes().as_ref().to_vec(), id, attempt };
+    let id = SignId { session: self.session, id, attempt };
 
     info!("signing for {} #{}", hex::encode(id.id), id.attempt);
 
@@ -603,7 +602,7 @@ impl<N: Network, D: Db> Signer<N, D> {
 
       CoordinatorMessage::Reattempt { id } => self.attempt(txn, id.id, id.attempt).await,
 
-      CoordinatorMessage::Completed { key: _, id, tx: mut tx_vec } => {
+      CoordinatorMessage::Completed { session: _, id, tx: mut tx_vec } => {
         let mut tx = <N::Transaction as Transaction<N>>::Id::default();
         if tx.as_ref().len() != tx_vec.len() {
           let true_len = tx_vec.len();
diff --git a/processor/src/tests/addresses.rs b/processor/src/tests/addresses.rs
index 6fec102f7..8d7baa9ed 100644
--- a/processor/src/tests/addresses.rs
+++ b/processor/src/tests/addresses.rs
@@ -7,6 +7,8 @@ use frost::{Participant, ThresholdKeys};
 
 use tokio::time::timeout;
 
+use serai_client::validator_sets::primitives::Session;
+
 use serai_db::{DbTxn, MemDb};
 
 use crate::{
@@ -50,7 +52,7 @@ async fn spend<N: Network, D: Db>(
       ),
     );
   }
-  sign(network.clone(), keys_txs).await;
+  sign(network.clone(), Session(0), keys_txs).await;
 
   for _ in 0 .. N::CONFIRMATIONS {
     network.mine_block().await;
diff --git a/processor/src/tests/batch_signer.rs b/processor/src/tests/batch_signer.rs
index 379ff9aad..0564db5ae 100644
--- a/processor/src/tests/batch_signer.rs
+++ b/processor/src/tests/batch_signer.rs
@@ -14,7 +14,8 @@ use sp_application_crypto::{RuntimePublic, sr25519::Public};
 use serai_db::{DbTxn, Db, MemDb};
 
 use scale::Encode;
-use serai_client::{primitives::*, in_instructions::primitives::*};
+#[rustfmt::skip]
+use serai_client::{primitives::*, in_instructions::primitives::*, validator_sets::primitives::Session};
 
 use messages::{
   substrate,
@@ -49,7 +50,7 @@ async fn test_batch_signer() {
   };
 
   let actual_id = SubstrateSignId {
-    key: keys.values().next().unwrap().group_key().to_bytes(),
+    session: Session(0),
     id: SubstrateSignableId::Batch((batch.network, batch.id).encode().try_into().unwrap()),
     attempt: 0,
   };
@@ -73,7 +74,7 @@ async fn test_batch_signer() {
     let i = Participant::new(u16::try_from(i).unwrap()).unwrap();
     let keys = keys.get(&i).unwrap().clone();
 
-    let mut signer = BatchSigner::<MemDb>::new(NetworkId::Monero, vec![keys]);
+    let mut signer = BatchSigner::<MemDb>::new(NetworkId::Monero, Session(0), vec![keys]);
     let mut db = MemDb::new();
 
     let mut txn = db.txn();
diff --git a/processor/src/tests/cosigner.rs b/processor/src/tests/cosigner.rs
index 7af794520..b7cc1a80a 100644
--- a/processor/src/tests/cosigner.rs
+++ b/processor/src/tests/cosigner.rs
@@ -13,7 +13,7 @@ use sp_application_crypto::{RuntimePublic, sr25519::Public};
 
 use serai_db::{DbTxn, Db, MemDb};
 
-use serai_client::primitives::*;
+use serai_client::{primitives::*, validator_sets::primitives::Session};
 
 use messages::coordinator::*;
 use crate::cosigner::Cosigner;
@@ -28,7 +28,7 @@ async fn test_cosigner() {
   let block = [0xaa; 32];
 
   let actual_id = SubstrateSignId {
-    key: keys.values().next().unwrap().group_key().to_bytes(),
+    session: Session(0),
     id: SubstrateSignableId::CosigningSubstrateBlock(block),
     attempt: (OsRng.next_u64() >> 32).try_into().unwrap(),
   };
@@ -55,7 +55,8 @@ async fn test_cosigner() {
     let mut db = MemDb::new();
     let mut txn = db.txn();
     let (signer, preprocess) =
-      Cosigner::new(&mut txn, vec![keys], block_number, block, actual_id.attempt).unwrap();
+      Cosigner::new(&mut txn, Session(0), vec![keys], block_number, block, actual_id.attempt)
+        .unwrap();
 
     match preprocess {
       // All participants should emit a preprocess
diff --git a/processor/src/tests/key_gen.rs b/processor/src/tests/key_gen.rs
index 90f11fbb2..beb158da4 100644
--- a/processor/src/tests/key_gen.rs
+++ b/processor/src/tests/key_gen.rs
@@ -10,10 +10,7 @@ use frost::{Participant, ThresholdParams, tests::clone_without};
 use serai_db::{DbTxn, Db, MemDb};
 
 use sp_application_crypto::sr25519;
-use serai_client::{
-  primitives::NetworkId,
-  validator_sets::primitives::{Session, ValidatorSet, KeyPair},
-};
+use serai_client::validator_sets::primitives::{Session, KeyPair};
 
 use messages::key_gen::*;
 use crate::{
@@ -21,8 +18,7 @@ use crate::{
   key_gen::{KeyConfirmed, KeyGen},
 };
 
-const ID: KeyGenId =
-  KeyGenId { set: ValidatorSet { session: Session(1), network: NetworkId::Monero }, attempt: 3 };
+const ID: KeyGenId = KeyGenId { session: Session(1), attempt: 3 };
 
 pub async fn test_key_gen<N: Network>() {
   let mut entropies = HashMap::new();
@@ -139,7 +135,11 @@ pub async fn test_key_gen<N: Network>() {
     let key_gen = key_gens.get_mut(&i).unwrap();
     let mut txn = dbs.get_mut(&i).unwrap().txn();
     let KeyConfirmed { mut substrate_keys, mut network_keys } = key_gen
-      .confirm(&mut txn, ID.set, KeyPair(sr25519::Public(res.0), res.1.clone().try_into().unwrap()))
+      .confirm(
+        &mut txn,
+        ID.session,
+        KeyPair(sr25519::Public(res.0), res.1.clone().try_into().unwrap()),
+      )
       .await;
     txn.commit();
 
diff --git a/processor/src/tests/signer.rs b/processor/src/tests/signer.rs
index cdb9f0cd6..9f76ae85f 100644
--- a/processor/src/tests/signer.rs
+++ b/processor/src/tests/signer.rs
@@ -2,7 +2,6 @@ use std::collections::HashMap;
 
 use rand_core::{RngCore, OsRng};
 
-use ciphersuite::group::GroupEncoding;
 use frost::{
   Participant, ThresholdKeys,
   dkg::tests::{key_gen, clone_without},
@@ -10,7 +9,10 @@ use frost::{
 
 use serai_db::{DbTxn, Db, MemDb};
 
-use serai_client::primitives::{NetworkId, Coin, Amount, Balance};
+use serai_client::{
+  primitives::{NetworkId, Coin, Amount, Balance},
+  validator_sets::primitives::Session,
+};
 
 use messages::sign::*;
 use crate::{
@@ -22,22 +24,17 @@ use crate::{
 #[allow(clippy::type_complexity)]
 pub async fn sign<N: Network>(
   network: N,
+  session: Session,
   mut keys_txs: HashMap<
     Participant,
     (ThresholdKeys<N::Curve>, (N::SignableTransaction, N::Eventuality)),
   >,
 ) -> <N::Transaction as Transaction<N>>::Id {
-  let actual_id = SignId {
-    key: keys_txs[&Participant::new(1).unwrap()].0.group_key().to_bytes().as_ref().to_vec(),
-    id: [0xaa; 32],
-    attempt: 0,
-  };
+  let actual_id = SignId { session, id: [0xaa; 32], attempt: 0 };
 
-  let mut group_key = None;
   let mut keys = HashMap::new();
   let mut txs = HashMap::new();
   for (i, (these_keys, this_tx)) in keys_txs.drain() {
-    group_key = Some(these_keys.group_key());
     keys.insert(i, these_keys);
     txs.insert(i, this_tx);
   }
@@ -49,7 +46,7 @@ pub async fn sign<N: Network>(
     let i = Participant::new(u16::try_from(i).unwrap()).unwrap();
     let keys = keys.remove(&i).unwrap();
     t = keys.params().t();
-    signers.insert(i, Signer::<_, MemDb>::new(network.clone(), vec![keys]));
+    signers.insert(i, Signer::<_, MemDb>::new(network.clone(), Session(0), vec![keys]));
     dbs.insert(i, MemDb::new());
   }
   drop(keys);
@@ -130,8 +127,8 @@ pub async fn sign<N: Network>(
       .await
       .unwrap()
     {
-      ProcessorMessage::Completed { key, id, tx } => {
-        assert_eq!(&key, group_key.unwrap().to_bytes().as_ref());
+      ProcessorMessage::Completed { session, id, tx } => {
+        assert_eq!(session, Session(0));
         assert_eq!(id, actual_id.id);
         if tx_id.is_none() {
           tx_id = Some(tx.clone());
@@ -196,7 +193,7 @@ pub async fn test_signer<N: Network>(network: N) {
 
   // The signer may not publish the TX if it has a connection error
   // It doesn't fail in this case
-  let txid = sign(network.clone(), keys_txs).await;
+  let txid = sign(network.clone(), Session(0), keys_txs).await;
   let tx = network.get_transaction(&txid).await.unwrap();
   assert_eq!(tx.id(), txid);
   // Mine a block, and scan it, to ensure that the TX actually made it on chain
diff --git a/processor/src/tests/wallet.rs b/processor/src/tests/wallet.rs
index c0248c7e2..74a6dd54f 100644
--- a/processor/src/tests/wallet.rs
+++ b/processor/src/tests/wallet.rs
@@ -8,7 +8,10 @@ use tokio::time::timeout;
 
 use serai_db::{DbTxn, Db, MemDb};
 
-use serai_client::primitives::{NetworkId, Coin, Amount, Balance};
+use serai_client::{
+  primitives::{NetworkId, Coin, Amount, Balance},
+  validator_sets::primitives::Session,
+};
 
 use crate::{
   Payment, Plan,
@@ -140,7 +143,7 @@ pub async fn test_wallet<N: Network>(network: N) {
     keys_txs.insert(i, (keys, (signable, eventuality)));
   }
 
-  let txid = sign(network.clone(), keys_txs).await;
+  let txid = sign(network.clone(), Session(0), keys_txs).await;
   let tx = network.get_transaction(&txid).await.unwrap();
   network.mine_block().await;
   let block_number = network.get_latest_block_number().await.unwrap();
diff --git a/tests/coordinator/src/tests/batch.rs b/tests/coordinator/src/tests/batch.rs
index 0e56f5adf..a3024c590 100644
--- a/tests/coordinator/src/tests/batch.rs
+++ b/tests/coordinator/src/tests/batch.rs
@@ -22,6 +22,7 @@ use serai_client::{
     primitives::{Batch, SignedBatch, batch_message},
     InInstructionsEvent,
   },
+  validator_sets::primitives::Session,
 };
 use messages::{
   coordinator::{SubstrateSignableId, SubstrateSignId},
@@ -33,16 +34,13 @@ use crate::{*, tests::*};
 pub async fn batch(
   processors: &mut [Processor],
   processor_is: &[u8],
+  session: Session,
   substrate_key: &Zeroizing<<Ristretto as Ciphersuite>::F>,
   batch: Batch,
 ) -> u64 {
   let mut id = [0; 5];
   OsRng.fill_bytes(&mut id);
-  let id = SubstrateSignId {
-    key: (<Ristretto as Ciphersuite>::generator() * **substrate_key).to_bytes(),
-    id: SubstrateSignableId::Batch(id),
-    attempt: 0,
-  };
+  let id = SubstrateSignId { session, id: SubstrateSignableId::Batch(id), attempt: 0 };
 
   for processor in processors.iter_mut() {
     processor
@@ -232,7 +230,6 @@ pub async fn batch(
             serai_time: last_block.time().unwrap() / 1000,
             network_latest_finalized_block: batch.batch.block,
           },
-          network: batch.batch.network,
           block: last_serai_block,
           burns: vec![],
           batches: vec![batch.batch.id],
@@ -244,7 +241,6 @@ pub async fn batch(
     processor
       .send_message(messages::ProcessorMessage::Coordinator(
         messages::coordinator::ProcessorMessage::SubstrateBlockAck {
-          network: batch.batch.network,
           block: last_serai_block,
           plans: vec![],
         },
@@ -283,6 +279,7 @@ async fn batch_test() {
       batch(
         &mut processors,
         &processor_is,
+        Session(0),
         &substrate_key,
         Batch {
           network: NetworkId::Bitcoin,
diff --git a/tests/coordinator/src/tests/key_gen.rs b/tests/coordinator/src/tests/key_gen.rs
index de294571d..59b1fbf51 100644
--- a/tests/coordinator/src/tests/key_gen.rs
+++ b/tests/coordinator/src/tests/key_gen.rs
@@ -28,7 +28,7 @@ pub async fn key_gen<C: Ciphersuite>(
   let mut participant_is = vec![];
 
   let set = ValidatorSet { session: Session(0), network: NetworkId::Bitcoin };
-  let id = KeyGenId { set, attempt: 0 };
+  let id = KeyGenId { session: set.session, attempt: 0 };
 
   for (i, processor) in processors.iter_mut().enumerate() {
     let msg = processor.recv_message().await;
@@ -173,7 +173,7 @@ pub async fn key_gen<C: Ciphersuite>(
         CoordinatorMessage::Substrate(
           messages::substrate::CoordinatorMessage::ConfirmKeyPair {
             context,
-            set: this_set,
+            session,
             ref key_pair,
           },
         ) => {
@@ -186,7 +186,7 @@ pub async fn key_gen<C: Ciphersuite>(
               70
           );
           assert_eq!(context.network_latest_finalized_block.0, [0; 32]);
-          assert_eq!(set, this_set);
+          assert_eq!(set.session, session);
           assert_eq!(key_pair.0 .0, substrate_key);
           assert_eq!(&key_pair.1, &network_key);
         }
diff --git a/tests/coordinator/src/tests/sign.rs b/tests/coordinator/src/tests/sign.rs
index cacf4fa8d..ce4b09189 100644
--- a/tests/coordinator/src/tests/sign.rs
+++ b/tests/coordinator/src/tests/sign.rs
@@ -4,10 +4,9 @@ use std::{
   collections::{HashSet, HashMap},
 };
 
-use zeroize::Zeroizing;
 use rand_core::{RngCore, OsRng};
 
-use ciphersuite::{group::GroupEncoding, Ciphersuite, Secp256k1};
+use ciphersuite::Secp256k1;
 
 use dkg::Participant;
 
@@ -22,23 +21,20 @@ use serai_client::{
     CoinsEvent,
   },
   in_instructions::primitives::{InInstruction, InInstructionWithBalance, Batch},
+  validator_sets::primitives::Session,
   SeraiCoins,
 };
 use messages::{coordinator::PlanMeta, sign::SignId, SubstrateContext, CoordinatorMessage};
 
 use crate::tests::*;
 
-pub async fn sign<C: Ciphersuite>(
+pub async fn sign(
   processors: &mut [Processor],
   processor_is: &[u8],
-  network_key: &Zeroizing<C::F>,
+  session: Session,
   plan_id: [u8; 32],
 ) {
-  let id = SignId {
-    key: (C::generator() * **network_key).to_bytes().as_ref().to_vec(),
-    id: plan_id,
-    attempt: 0,
-  };
+  let id = SignId { session, id: plan_id, attempt: 0 };
 
   // Select a random participant to exclude, so we know for sure who *is* participating
   assert_eq!(COORDINATORS - THRESHOLD, 1);
@@ -150,7 +146,7 @@ pub async fn sign<C: Ciphersuite>(
       &mut processors[processor_is.iter().position(|p_i| u16::from(*p_i) == u16::from(i)).unwrap()];
     processor
       .send_message(messages::sign::ProcessorMessage::Completed {
-        key: id.key.clone(),
+        session,
         id: id.id,
         tx: b"signed_tx".to_vec(),
       })
@@ -163,7 +159,7 @@ pub async fn sign<C: Ciphersuite>(
     assert_eq!(
       processor.recv_message().await,
       CoordinatorMessage::Sign(messages::sign::CoordinatorMessage::Completed {
-        key: id.key.clone(),
+        session,
         id: id.id,
         tx: b"signed_tx".to_vec()
       })
@@ -196,8 +192,7 @@ async fn sign_test() {
       }
       let mut processors = new_processors;
 
-      let (participant_is, substrate_key, network_key) =
-        key_gen::<Secp256k1>(&mut processors).await;
+      let (participant_is, substrate_key, _) = key_gen::<Secp256k1>(&mut processors).await;
 
       // 'Send' external coins into Serai
       let serai = processors[0].serai().await;
@@ -230,6 +225,7 @@ async fn sign_test() {
       let block_included_in = batch(
         &mut processors,
         &participant_is,
+        Session(0),
         &substrate_key,
         Batch {
           network: NetworkId::Bitcoin,
@@ -331,7 +327,6 @@ async fn sign_test() {
                 serai_time: last_serai_block.time().unwrap() / 1000,
                 network_latest_finalized_block: coin_block,
               },
-              network: NetworkId::Bitcoin,
               block: last_serai_block.number(),
               burns: vec![out_instruction.clone()],
               batches: vec![],
@@ -343,18 +338,14 @@ async fn sign_test() {
         processor
           .send_message(messages::ProcessorMessage::Coordinator(
             messages::coordinator::ProcessorMessage::SubstrateBlockAck {
-              network: NetworkId::Bitcoin,
               block: last_serai_block.number(),
-              plans: vec![PlanMeta {
-                key: (Secp256k1::generator() * *network_key).to_bytes().to_vec(),
-                id: plan_id,
-              }],
+              plans: vec![PlanMeta { session: Session(0), id: plan_id }],
             },
           ))
           .await;
       }
 
-      sign::<Secp256k1>(&mut processors, &participant_is, &network_key, plan_id).await;
+      sign(&mut processors, &participant_is, Session(0), plan_id).await;
     })
     .await;
 }
diff --git a/tests/processor/src/tests/batch.rs b/tests/processor/src/tests/batch.rs
index 38aaca614..9c678b983 100644
--- a/tests/processor/src/tests/batch.rs
+++ b/tests/processor/src/tests/batch.rs
@@ -15,6 +15,7 @@ use serai_client::{
   in_instructions::primitives::{
     InInstruction, InInstructionWithBalance, Batch, SignedBatch, batch_message,
   },
+  validator_sets::primitives::Session,
 };
 
 use processor::networks::{Network, Bitcoin, Monero};
@@ -23,12 +24,12 @@ use crate::{*, tests::*};
 
 pub(crate) async fn recv_batch_preprocesses(
   coordinators: &mut [Coordinator],
-  substrate_key: &[u8; 32],
+  session: Session,
   batch: &Batch,
   attempt: u32,
 ) -> (SubstrateSignId, HashMap<Participant, [u8; 64]>) {
   let id = SubstrateSignId {
-    key: *substrate_key,
+    session,
     id: SubstrateSignableId::Batch((batch.network, batch.id).encode().try_into().unwrap()),
     attempt,
   };
@@ -171,7 +172,6 @@ pub(crate) async fn substrate_block(
   match block.clone() {
     messages::substrate::CoordinatorMessage::SubstrateBlock {
       context: _,
-      network: sent_network,
       block: sent_block,
       burns: _,
       batches: _,
@@ -179,13 +179,8 @@ pub(crate) async fn substrate_block(
       coordinator.send_message(block).await;
       match coordinator.recv_message().await {
         messages::ProcessorMessage::Coordinator(
-          messages::coordinator::ProcessorMessage::SubstrateBlockAck {
-            network: recvd_network,
-            block: recvd_block,
-            plans,
-          },
+          messages::coordinator::ProcessorMessage::SubstrateBlockAck { block: recvd_block, plans },
         ) => {
-          assert_eq!(recvd_network, sent_network);
           assert_eq!(recvd_block, sent_block);
           plans
         }
@@ -214,7 +209,7 @@ fn batch_test() {
       coordinators[0].sync(&ops, &coordinators[1 ..]).await;
 
       // Generate keys
-      let key_pair = key_gen(&mut coordinators, network).await;
+      let key_pair = key_gen(&mut coordinators).await;
 
       // Now we we have to mine blocks to activate the key
       // (the first key is activated when the network's time as of a block exceeds the Serai time
@@ -284,7 +279,7 @@ fn batch_test() {
 
         // Make sure the processors picked it up by checking they're trying to sign a batch for it
         let (mut id, mut preprocesses) =
-          recv_batch_preprocesses(&mut coordinators, &key_pair.0 .0, &expected_batch, 0).await;
+          recv_batch_preprocesses(&mut coordinators, Session(0), &expected_batch, 0).await;
         // Trigger a random amount of re-attempts
         for attempt in 1 ..= u32::try_from(OsRng.next_u64() % 4).unwrap() {
           // TODO: Double check how the processor handles this ID field
@@ -298,8 +293,7 @@ fn batch_test() {
               .await;
           }
           (id, preprocesses) =
-            recv_batch_preprocesses(&mut coordinators, &key_pair.0 .0, &expected_batch, attempt)
-              .await;
+            recv_batch_preprocesses(&mut coordinators, Session(0), &expected_batch, attempt).await;
         }
 
         // Continue with signing the batch
@@ -319,7 +313,6 @@ fn batch_test() {
                 serai_time,
                 network_latest_finalized_block: batch.batch.block,
               },
-              network,
               block: substrate_block_num + u64::from(i),
               burns: vec![],
               batches: vec![batch.batch.id],
diff --git a/tests/processor/src/tests/key_gen.rs b/tests/processor/src/tests/key_gen.rs
index c5640819d..b98ec04eb 100644
--- a/tests/processor/src/tests/key_gen.rs
+++ b/tests/processor/src/tests/key_gen.rs
@@ -4,14 +4,14 @@ use dkg::{Participant, ThresholdParams, tests::clone_without};
 
 use serai_client::{
   primitives::{NetworkId, BlockHash, PublicKey},
-  validator_sets::primitives::{Session, ValidatorSet, KeyPair},
+  validator_sets::primitives::{Session, KeyPair},
 };
 
 use messages::{SubstrateContext, key_gen::KeyGenId, CoordinatorMessage, ProcessorMessage};
 
 use crate::{*, tests::*};
 
-pub(crate) async fn key_gen(coordinators: &mut [Coordinator], network: NetworkId) -> KeyPair {
+pub(crate) async fn key_gen(coordinators: &mut [Coordinator]) -> KeyPair {
   // Perform an interaction with all processors via their coordinators
   async fn interact_with_all<
     FS: Fn(Participant) -> messages::key_gen::CoordinatorMessage,
@@ -33,7 +33,7 @@ pub(crate) async fn key_gen(coordinators: &mut [Coordinator], network: NetworkId
   }
 
   // Order a key gen
-  let id = KeyGenId { set: ValidatorSet { session: Session(0), network }, attempt: 0 };
+  let id = KeyGenId { session: Session(0), attempt: 0 };
 
   let mut commitments = HashMap::new();
   interact_with_all(
@@ -132,7 +132,7 @@ pub(crate) async fn key_gen(coordinators: &mut [Coordinator], network: NetworkId
       .send_message(CoordinatorMessage::Substrate(
         messages::substrate::CoordinatorMessage::ConfirmKeyPair {
           context,
-          set: id.set,
+          session: id.session,
           key_pair: key_pair.clone(),
         },
       ))
@@ -158,7 +158,7 @@ fn key_gen_test() {
         .map(|(handles, key)| Coordinator::new(network, &ops, handles, key))
         .collect::<Vec<_>>();
 
-      key_gen(&mut coordinators, network).await;
+      key_gen(&mut coordinators).await;
     });
   }
 }
diff --git a/tests/processor/src/tests/send.rs b/tests/processor/src/tests/send.rs
index 227cc0c5f..986671c16 100644
--- a/tests/processor/src/tests/send.rs
+++ b/tests/processor/src/tests/send.rs
@@ -9,8 +9,9 @@ use messages::{sign::SignId, SubstrateContext};
 
 use serai_client::{
   primitives::{BlockHash, NetworkId},
-  in_instructions::primitives::Batch,
   coins::primitives::{OutInstruction, OutInstructionWithBalance},
+  in_instructions::primitives::Batch,
+  validator_sets::primitives::Session,
 };
 
 use crate::{*, tests::*};
@@ -18,7 +19,7 @@ use crate::{*, tests::*};
 #[allow(unused)]
 pub(crate) async fn recv_sign_preprocesses(
   coordinators: &mut [Coordinator],
-  key: Vec<u8>,
+  session: Session,
   attempt: u32,
 ) -> (SignId, HashMap<Participant, Vec<u8>>) {
   let mut id = None;
@@ -33,7 +34,7 @@ pub(crate) async fn recv_sign_preprocesses(
         preprocesses: mut these_preprocesses,
       }) => {
         if id.is_none() {
-          assert_eq!(&this_id.key, &key);
+          assert_eq!(&this_id.session, &session);
           assert_eq!(this_id.attempt, attempt);
           id = Some(this_id.clone());
         }
@@ -62,6 +63,7 @@ pub(crate) async fn recv_sign_preprocesses(
 #[allow(unused)]
 pub(crate) async fn sign_tx(
   coordinators: &mut [Coordinator],
+  session: Session,
   id: SignId,
   preprocesses: HashMap<Participant, Vec<u8>>,
 ) -> Vec<u8> {
@@ -120,11 +122,11 @@ pub(crate) async fn sign_tx(
     if preprocesses.contains_key(&i) {
       match coordinator.recv_message().await {
         messages::ProcessorMessage::Sign(messages::sign::ProcessorMessage::Completed {
-          key,
+          session: this_session,
           id: this_id,
           tx: this_tx,
         }) => {
-          assert_eq!(&key, &id.key);
+          assert_eq!(session, this_session);
           assert_eq!(&this_id, &id.id);
 
           if tx.is_none() {
@@ -158,7 +160,7 @@ fn send_test() {
       coordinators[0].sync(&ops, &coordinators[1 ..]).await;
 
       // Generate keys
-      let key_pair = key_gen(&mut coordinators, network).await;
+      let key_pair = key_gen(&mut coordinators).await;
 
       // Now we we have to mine blocks to activate the key
       // (the first key is activated when the network's time as of a block exceeds the Serai time
@@ -195,7 +197,7 @@ fn send_test() {
 
       // Make sure the proceessors picked it up by checking they're trying to sign a batch for it
       let (id, preprocesses) =
-        recv_batch_preprocesses(&mut coordinators, &key_pair.0 .0, &expected_batch, 0).await;
+        recv_batch_preprocesses(&mut coordinators, Session(0), &expected_batch, 0).await;
 
       // Continue with signing the batch
       let batch = sign_batch(&mut coordinators, key_pair.0 .0, id, preprocesses).await;
@@ -216,7 +218,6 @@ fn send_test() {
               serai_time,
               network_latest_finalized_block: batch.batch.block,
             },
-            network,
             block: substrate_block_num,
             burns: vec![OutInstructionWithBalance {
               instruction: OutInstruction { address: wallet.address(), data: None },
@@ -237,9 +238,8 @@ fn send_test() {
 
       // Start signing the TX
       let (mut id, mut preprocesses) =
-        recv_sign_preprocesses(&mut coordinators, key_pair.1.to_vec(), 0).await;
-      // TODO: Should this use the Substrate key?
-      assert_eq!(id, SignId { key: key_pair.1.to_vec(), id: plans[0].id, attempt: 0 });
+        recv_sign_preprocesses(&mut coordinators, Session(0), 0).await;
+      assert_eq!(id, SignId { session: Session(0), id: plans[0].id, attempt: 0 });
 
       // Trigger a random amount of re-attempts
       for attempt in 1 ..= u32::try_from(OsRng.next_u64() % 4).unwrap() {
@@ -251,12 +251,11 @@ fn send_test() {
             .send_message(messages::sign::CoordinatorMessage::Reattempt { id: id.clone() })
             .await;
         }
-        (id, preprocesses) =
-          recv_sign_preprocesses(&mut coordinators, key_pair.1.to_vec(), attempt).await;
+        (id, preprocesses) = recv_sign_preprocesses(&mut coordinators, Session(0), attempt).await;
       }
       let participating = preprocesses.keys().cloned().collect::<Vec<_>>();
 
-      let tx_id = sign_tx(&mut coordinators, id.clone(), preprocesses).await;
+      let tx_id = sign_tx(&mut coordinators, Session(0), id.clone(), preprocesses).await;
 
       // Make sure all participating nodes published the TX
       let participating =
@@ -276,7 +275,7 @@ fn send_test() {
           // Tell them of it as a completion of the relevant signing nodess
           coordinator
             .send_message(messages::sign::CoordinatorMessage::Completed {
-              key: key_pair.1.to_vec(),
+              session: Session(0),
               id: id.id,
               tx: tx_id.clone(),
             })
@@ -284,11 +283,11 @@ fn send_test() {
           // Verify they send Completed back
           match coordinator.recv_message().await {
             messages::ProcessorMessage::Sign(messages::sign::ProcessorMessage::Completed {
-              key,
+              session,
               id: this_id,
               tx: this_tx,
             }) => {
-              assert_eq!(&key, &id.key);
+              assert_eq!(session, Session(0));
               assert_eq!(&this_id, &id.id);
               assert_eq!(this_tx, tx_id);
             }