From c03fb6c71b8bd1fa89690ea2c110de2fa5abd942 Mon Sep 17 00:00:00 2001
From: Luke Parker <lukeparker5132@gmail.com>
Date: Mon, 6 Nov 2023 19:50:32 -0500
Subject: [PATCH] Add dedicated BatchSignId

---
 coins/bitcoin/src/wallet/send.rs           |  2 +-
 coordinator/src/db.rs                      |  6 +--
 coordinator/src/main.rs                    | 14 +++----
 coordinator/src/tests/tributary/mod.rs     | 11 ++++--
 coordinator/src/tributary/db.rs            |  2 +-
 coordinator/src/tributary/handle.rs        | 14 +++----
 coordinator/src/tributary/mod.rs           | 20 +++++-----
 coordinator/src/tributary/nonce_decider.rs | 34 +++++++---------
 coordinator/src/tributary/scanner.rs       |  4 +-
 processor/messages/src/lib.rs              | 21 ++++++----
 processor/src/networks/monero.rs           |  2 +-
 processor/src/substrate_signer.rs          | 45 +++++++++-------------
 processor/src/tests/substrate_signer.rs    | 17 ++++----
 tests/coordinator/src/tests/batch.rs       |  8 ++--
 tests/coordinator/src/tests/key_gen.rs     |  2 +-
 tests/processor/src/networks.rs            |  3 +-
 tests/processor/src/tests/batch.rs         | 23 ++++++-----
 17 files changed, 112 insertions(+), 116 deletions(-)

diff --git a/coins/bitcoin/src/wallet/send.rs b/coins/bitcoin/src/wallet/send.rs
index 81adbda8..e6997c5b 100644
--- a/coins/bitcoin/src/wallet/send.rs
+++ b/coins/bitcoin/src/wallet/send.rs
@@ -94,7 +94,7 @@ impl SignableTransaction {
       // the value is fixed size (so any value could be used here)
       tx.output.push(TxOut { value: Amount::ZERO, script_pubkey: change.script_pubkey() });
     }
-    u64::try_from(tx.weight()).unwrap()
+    u64::from(tx.weight())
   }
 
   /// Returns the fee necessary for this transaction to achieve the fee rate specified at
diff --git a/coordinator/src/db.rs b/coordinator/src/db.rs
index c93ce56b..7be798b6 100644
--- a/coordinator/src/db.rs
+++ b/coordinator/src/db.rs
@@ -106,14 +106,14 @@ impl<D: Db> MainDb<D> {
     res
   }
 
-  fn first_preprocess_key(network: NetworkId, id_type: RecognizedIdType, id: [u8; 32]) -> Vec<u8> {
+  fn first_preprocess_key(network: NetworkId, id_type: RecognizedIdType, id: &[u8]) -> Vec<u8> {
     Self::main_key(b"first_preprocess", (network, id_type, id).encode())
   }
   pub fn save_first_preprocess(
     txn: &mut D::Transaction<'_>,
     network: NetworkId,
     id_type: RecognizedIdType,
-    id: [u8; 32],
+    id: &[u8],
     preprocess: Vec<Vec<u8>>,
   ) {
     let preprocess = preprocess.encode();
@@ -128,7 +128,7 @@ impl<D: Db> MainDb<D> {
     getter: &G,
     network: NetworkId,
     id_type: RecognizedIdType,
-    id: [u8; 32],
+    id: &[u8],
   ) -> Option<Vec<Vec<u8>>> {
     getter
       .get(Self::first_preprocess_key(network, id_type, id))
diff --git a/coordinator/src/main.rs b/coordinator/src/main.rs
index ab00e945..905fc4e5 100644
--- a/coordinator/src/main.rs
+++ b/coordinator/src/main.rs
@@ -488,7 +488,7 @@ async fn handle_processor_message<D: Db, P: P2p>(
               &mut txn,
               network,
               RecognizedIdType::Plan,
-              id.id,
+              &id.id,
               preprocesses,
             );
 
@@ -547,7 +547,7 @@ async fn handle_processor_message<D: Db, P: P2p>(
               &mut txn,
               spec.set().network,
               RecognizedIdType::Batch,
-              id.id,
+              &id.id,
               preprocesses,
             );
 
@@ -877,7 +877,7 @@ pub async fn run<D: Db, Pro: Processors, P: P2p>(
       }
     });
 
-    move |set: ValidatorSet, genesis, id_type, id, nonce| {
+    move |set: ValidatorSet, genesis, id_type, id: Vec<u8>, nonce| {
       let mut raw_db = raw_db.clone();
       let key = key.clone();
       let tributaries = tributaries.clone();
@@ -899,16 +899,16 @@ pub async fn run<D: Db, Pro: Processors, P: P2p>(
 
         let mut tx = match id_type {
           RecognizedIdType::Batch => Transaction::BatchPreprocess(SignData {
-            plan: id,
+            data: get_preprocess(&raw_db, id_type, &id).await,
+            plan: id.try_into().unwrap(),
             attempt: 0,
-            data: get_preprocess(&raw_db, id_type, id).await,
             signed: Transaction::empty_signed(),
           }),
 
           RecognizedIdType::Plan => Transaction::SignPreprocess(SignData {
-            plan: id,
+            data: get_preprocess(&raw_db, id_type, &id).await,
+            plan: id.try_into().unwrap(),
             attempt: 0,
-            data: get_preprocess(&raw_db, id_type, id).await,
             signed: Transaction::empty_signed(),
           }),
         };
diff --git a/coordinator/src/tests/tributary/mod.rs b/coordinator/src/tests/tributary/mod.rs
index 4a67d18d..b8061d34 100644
--- a/coordinator/src/tests/tributary/mod.rs
+++ b/coordinator/src/tests/tributary/mod.rs
@@ -28,8 +28,8 @@ fn random_vec<R: RngCore>(rng: &mut R, limit: usize) -> Vec<u8> {
   res
 }
 
-fn random_sign_data<R: RngCore>(rng: &mut R) -> SignData {
-  let mut plan = [0; 32];
+fn random_sign_data<R: RngCore, const N: usize>(rng: &mut R) -> SignData<N> {
+  let mut plan = [0; N];
   rng.fill_bytes(&mut plan);
 
   SignData {
@@ -80,7 +80,10 @@ fn tx_size_limit() {
 
 #[test]
 fn serialize_sign_data() {
-  test_read_write(random_sign_data(&mut OsRng));
+  test_read_write(random_sign_data::<_, 3>(&mut OsRng));
+  test_read_write(random_sign_data::<_, 8>(&mut OsRng));
+  test_read_write(random_sign_data::<_, 16>(&mut OsRng));
+  test_read_write(random_sign_data::<_, 24>(&mut OsRng));
 }
 
 #[test]
@@ -143,7 +146,7 @@ fn serialize_transaction() {
   {
     let mut block = [0; 32];
     OsRng.fill_bytes(&mut block);
-    let mut batch = [0; 32];
+    let mut batch = [0; 5];
     OsRng.fill_bytes(&mut batch);
     test_read_write(Transaction::Batch(block, batch));
   }
diff --git a/coordinator/src/tributary/db.rs b/coordinator/src/tributary/db.rs
index aedd37e0..0fb26375 100644
--- a/coordinator/src/tributary/db.rs
+++ b/coordinator/src/tributary/db.rs
@@ -16,7 +16,7 @@ use crate::tributary::TributarySpec;
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
 pub enum Topic {
   Dkg,
-  Batch([u8; 32]),
+  Batch([u8; 5]),
   Sign([u8; 32]),
 }
 
diff --git a/coordinator/src/tributary/handle.rs b/coordinator/src/tributary/handle.rs
index ebc44248..25334062 100644
--- a/coordinator/src/tributary/handle.rs
+++ b/coordinator/src/tributary/handle.rs
@@ -18,7 +18,7 @@ use tributary::Signed;
 
 use processor_messages::{
   key_gen::{self, KeyGenId},
-  coordinator,
+  coordinator::{self, BatchSignId},
   sign::{self, SignId},
 };
 
@@ -370,7 +370,7 @@ pub(crate) async fn handle_application_tx<
       // Because this Batch has achieved synchrony, its batch ID should be authorized
       TributaryDb::<D>::recognize_topic(txn, genesis, Topic::Batch(batch));
       let nonce = NonceDecider::<D>::handle_batch(txn, genesis, batch);
-      recognized_id(spec.set(), genesis, RecognizedIdType::Batch, batch, nonce).await;
+      recognized_id(spec.set(), genesis, RecognizedIdType::Batch, batch.to_vec(), nonce).await;
     }
 
     Transaction::SubstrateBlock(block) => {
@@ -382,7 +382,7 @@ pub(crate) async fn handle_application_tx<
       let nonces = NonceDecider::<D>::handle_substrate_block(txn, genesis, &plan_ids);
       for (nonce, id) in nonces.into_iter().zip(plan_ids.into_iter()) {
         TributaryDb::<D>::recognize_topic(txn, genesis, Topic::Sign(id));
-        recognized_id(spec.set(), genesis, RecognizedIdType::Plan, id, nonce).await;
+        recognized_id(spec.set(), genesis, RecognizedIdType::Plan, id.to_vec(), nonce).await;
       }
     }
 
@@ -403,12 +403,12 @@ pub(crate) async fn handle_application_tx<
         Accumulation::Ready(DataSet::Participating(mut preprocesses)) => {
           unflatten(spec, &mut preprocesses);
           NonceDecider::<D>::selected_for_signing_batch(txn, genesis, data.plan);
-          let key = TributaryDb::<D>::key_pair(txn, spec.set()).unwrap().0 .0.to_vec();
+          let key = TributaryDb::<D>::key_pair(txn, spec.set()).unwrap().0 .0;
           processors
             .send(
               spec.set().network,
               coordinator::CoordinatorMessage::BatchPreprocesses {
-                id: SignId { key, id: data.plan, attempt: data.attempt },
+                id: BatchSignId { key, id: data.plan, attempt: data.attempt },
                 preprocesses,
               },
             )
@@ -434,12 +434,12 @@ pub(crate) async fn handle_application_tx<
       ) {
         Accumulation::Ready(DataSet::Participating(mut shares)) => {
           unflatten(spec, &mut shares);
-          let key = TributaryDb::<D>::key_pair(txn, spec.set()).unwrap().0 .0.to_vec();
+          let key = TributaryDb::<D>::key_pair(txn, spec.set()).unwrap().0 .0;
           processors
             .send(
               spec.set().network,
               coordinator::CoordinatorMessage::BatchShares {
-                id: SignId { key, id: data.plan, attempt: data.attempt },
+                id: BatchSignId { key, id: data.plan, attempt: data.attempt },
                 shares: shares
                   .into_iter()
                   .map(|(validator, share)| (validator, share.try_into().unwrap()))
diff --git a/coordinator/src/tributary/mod.rs b/coordinator/src/tributary/mod.rs
index 9d8c5a0b..2284d77b 100644
--- a/coordinator/src/tributary/mod.rs
+++ b/coordinator/src/tributary/mod.rs
@@ -167,8 +167,8 @@ impl TributarySpec {
 }
 
 #[derive(Clone, PartialEq, Eq, Debug)]
-pub struct SignData {
-  pub plan: [u8; 32],
+pub struct SignData<const N: usize> {
+  pub plan: [u8; N],
   pub attempt: u32,
 
   pub data: Vec<Vec<u8>>,
@@ -176,9 +176,9 @@ pub struct SignData {
   pub signed: Signed,
 }
 
-impl ReadWrite for SignData {
+impl<const N: usize> ReadWrite for SignData<N> {
   fn read<R: io::Read>(reader: &mut R) -> io::Result<Self> {
-    let mut plan = [0; 32];
+    let mut plan = [0; N];
     reader.read_exact(&mut plan)?;
 
     let mut attempt = [0; 4];
@@ -249,16 +249,16 @@ pub enum Transaction {
   // which would be binding over the block hash and automatically achieve synchrony on all
   // relevant batches. ExternalBlock was removed for this due to complexity around the pipeline
   // with the current processor, yet it would still be an improvement.
-  Batch([u8; 32], [u8; 32]),
+  Batch([u8; 32], [u8; 5]),
   // When a Serai block is finalized, with the contained batches, we can allow the associated plan
   // IDs
   SubstrateBlock(u64),
 
-  BatchPreprocess(SignData),
-  BatchShare(SignData),
+  BatchPreprocess(SignData<5>),
+  BatchShare(SignData<5>),
 
-  SignPreprocess(SignData),
-  SignShare(SignData),
+  SignPreprocess(SignData<32>),
+  SignShare(SignData<32>),
   // This is defined as an Unsigned transaction in order to de-duplicate SignCompleted amongst
   // reporters (who should all report the same thing)
   // We do still track the signer in order to prevent a single signer from publishing arbitrarily
@@ -367,7 +367,7 @@ impl ReadWrite for Transaction {
       3 => {
         let mut block = [0; 32];
         reader.read_exact(&mut block)?;
-        let mut batch = [0; 32];
+        let mut batch = [0; 5];
         reader.read_exact(&mut batch)?;
         Ok(Transaction::Batch(block, batch))
       }
diff --git a/coordinator/src/tributary/nonce_decider.rs b/coordinator/src/tributary/nonce_decider.rs
index 55cd6295..d2f1a918 100644
--- a/coordinator/src/tributary/nonce_decider.rs
+++ b/coordinator/src/tributary/nonce_decider.rs
@@ -27,31 +27,25 @@ impl<D: Db> NonceDecider<D> {
     next
   }
 
-  fn item_nonce_key(genesis: [u8; 32], code: u8, id: [u8; 32]) -> Vec<u8> {
+  fn item_nonce_key(genesis: [u8; 32], code: u8, id: &[u8]) -> Vec<u8> {
     D::key(
       b"coordinator_tributary_nonce",
       b"item",
-      [genesis.as_slice(), [code].as_ref(), id.as_ref()].concat(),
+      [genesis.as_slice(), [code].as_ref(), id].concat(),
     )
   }
-  fn set_nonce(
-    txn: &mut D::Transaction<'_>,
-    genesis: [u8; 32],
-    code: u8,
-    id: [u8; 32],
-    nonce: u32,
-  ) {
+  fn set_nonce(txn: &mut D::Transaction<'_>, genesis: [u8; 32], code: u8, id: &[u8], nonce: u32) {
     txn.put(Self::item_nonce_key(genesis, code, id), nonce.to_le_bytes())
   }
-  fn db_nonce<G: Get>(getter: &G, genesis: [u8; 32], code: u8, id: [u8; 32]) -> Option<u32> {
+  fn db_nonce<G: Get>(getter: &G, genesis: [u8; 32], code: u8, id: &[u8]) -> Option<u32> {
     getter
       .get(Self::item_nonce_key(genesis, code, id))
       .map(|bytes| u32::from_le_bytes(bytes.try_into().unwrap()))
   }
 
-  pub fn handle_batch(txn: &mut D::Transaction<'_>, genesis: [u8; 32], batch: [u8; 32]) -> u32 {
+  pub fn handle_batch(txn: &mut D::Transaction<'_>, genesis: [u8; 32], batch: [u8; 5]) -> u32 {
     let nonce_for = Self::allocate_nonce(txn, genesis);
-    Self::set_nonce(txn, genesis, BATCH_CODE, batch, nonce_for);
+    Self::set_nonce(txn, genesis, BATCH_CODE, &batch, nonce_for);
     nonce_for
   }
   // TODO: The processor won't yield shares for this if the signing protocol aborts. We need to
@@ -60,10 +54,10 @@ impl<D: Db> NonceDecider<D> {
   pub fn selected_for_signing_batch(
     txn: &mut D::Transaction<'_>,
     genesis: [u8; 32],
-    batch: [u8; 32],
+    batch: [u8; 5],
   ) {
     let nonce_for = Self::allocate_nonce(txn, genesis);
-    Self::set_nonce(txn, genesis, BATCH_SIGNING_CODE, batch, nonce_for);
+    Self::set_nonce(txn, genesis, BATCH_SIGNING_CODE, &batch, nonce_for);
   }
 
   pub fn handle_substrate_block(
@@ -74,7 +68,7 @@ impl<D: Db> NonceDecider<D> {
     let mut res = Vec::with_capacity(plans.len());
     for plan in plans {
       let nonce_for = Self::allocate_nonce(txn, genesis);
-      Self::set_nonce(txn, genesis, PLAN_CODE, *plan, nonce_for);
+      Self::set_nonce(txn, genesis, PLAN_CODE, plan, nonce_for);
       res.push(nonce_for);
     }
     res
@@ -86,7 +80,7 @@ impl<D: Db> NonceDecider<D> {
     plan: [u8; 32],
   ) {
     let nonce_for = Self::allocate_nonce(txn, genesis);
-    Self::set_nonce(txn, genesis, PLAN_SIGNING_CODE, plan, nonce_for);
+    Self::set_nonce(txn, genesis, PLAN_SIGNING_CODE, &plan, nonce_for);
   }
 
   pub fn nonce<G: Get>(getter: &G, genesis: [u8; 32], tx: &Transaction) -> Option<Option<u32>> {
@@ -109,20 +103,20 @@ impl<D: Db> NonceDecider<D> {
 
       Transaction::BatchPreprocess(data) => {
         assert_eq!(data.attempt, 0);
-        Some(Self::db_nonce(getter, genesis, BATCH_CODE, data.plan))
+        Some(Self::db_nonce(getter, genesis, BATCH_CODE, &data.plan))
       }
       Transaction::BatchShare(data) => {
         assert_eq!(data.attempt, 0);
-        Some(Self::db_nonce(getter, genesis, BATCH_SIGNING_CODE, data.plan))
+        Some(Self::db_nonce(getter, genesis, BATCH_SIGNING_CODE, &data.plan))
       }
 
       Transaction::SignPreprocess(data) => {
         assert_eq!(data.attempt, 0);
-        Some(Self::db_nonce(getter, genesis, PLAN_CODE, data.plan))
+        Some(Self::db_nonce(getter, genesis, PLAN_CODE, &data.plan))
       }
       Transaction::SignShare(data) => {
         assert_eq!(data.attempt, 0);
-        Some(Self::db_nonce(getter, genesis, PLAN_SIGNING_CODE, data.plan))
+        Some(Self::db_nonce(getter, genesis, PLAN_SIGNING_CODE, &data.plan))
       }
 
       Transaction::SignCompleted { .. } => None,
diff --git a/coordinator/src/tributary/scanner.rs b/coordinator/src/tributary/scanner.rs
index 78e71920..895c7754 100644
--- a/coordinator/src/tributary/scanner.rs
+++ b/coordinator/src/tributary/scanner.rs
@@ -35,10 +35,10 @@ pub enum RecognizedIdType {
 }
 
 pub(crate) trait RIDTrait<FRid>:
-  Clone + Fn(ValidatorSet, [u8; 32], RecognizedIdType, [u8; 32], u32) -> FRid
+  Clone + Fn(ValidatorSet, [u8; 32], RecognizedIdType, Vec<u8>, u32) -> FRid
 {
 }
-impl<FRid, F: Clone + Fn(ValidatorSet, [u8; 32], RecognizedIdType, [u8; 32], u32) -> FRid>
+impl<FRid, F: Clone + Fn(ValidatorSet, [u8; 32], RecognizedIdType, Vec<u8>, u32) -> FRid>
   RIDTrait<FRid> for F
 {
 }
diff --git a/processor/messages/src/lib.rs b/processor/messages/src/lib.rs
index 5b118434..317ad6ae 100644
--- a/processor/messages/src/lib.rs
+++ b/processor/messages/src/lib.rs
@@ -106,15 +106,22 @@ pub mod sign {
 }
 
 pub mod coordinator {
-  use super::{sign::SignId, *};
+  use super::*;
+
+  #[derive(Clone, PartialEq, Eq, Hash, Debug, Zeroize, Encode, Decode, Serialize, Deserialize)]
+  pub struct BatchSignId {
+    pub key: [u8; 32],
+    pub id: [u8; 5],
+    pub attempt: u32,
+  }
 
   #[derive(Clone, PartialEq, Eq, Debug, Serialize, Deserialize)]
   pub enum CoordinatorMessage {
     // Uses Vec<u8> instead of [u8; 64] since serde Deserialize isn't implemented for [u8; 64]
-    BatchPreprocesses { id: SignId, preprocesses: HashMap<Participant, Vec<u8>> },
-    BatchShares { id: SignId, shares: HashMap<Participant, [u8; 32]> },
+    BatchPreprocesses { id: BatchSignId, preprocesses: HashMap<Participant, Vec<u8>> },
+    BatchShares { id: BatchSignId, shares: HashMap<Participant, [u8; 32]> },
     // Re-attempt a batch signing protocol.
-    BatchReattempt { id: SignId },
+    BatchReattempt { id: BatchSignId },
   }
 
   impl CoordinatorMessage {
@@ -148,8 +155,8 @@ pub mod coordinator {
   #[derive(Clone, PartialEq, Eq, Debug, Zeroize, Encode, Decode, Serialize, Deserialize)]
   pub enum ProcessorMessage {
     SubstrateBlockAck { network: NetworkId, block: u64, plans: Vec<PlanMeta> },
-    BatchPreprocess { id: SignId, block: BlockHash, preprocesses: Vec<Vec<u8>> },
-    BatchShare { id: SignId, shares: Vec<[u8; 32]> },
+    BatchPreprocess { id: BatchSignId, block: BlockHash, preprocesses: Vec<Vec<u8>> },
+    BatchShare { id: BatchSignId, shares: Vec<[u8; 32]> },
   }
 }
 
@@ -359,7 +366,7 @@ impl ProcessorMessage {
           coordinator::ProcessorMessage::SubstrateBlockAck { network, block, .. } => {
             (0, (network, block).encode())
           }
-          // Unique since SignId
+          // Unique since BatchSignId
           coordinator::ProcessorMessage::BatchPreprocess { id, .. } => (1, id.encode()),
           coordinator::ProcessorMessage::BatchShare { id, .. } => (2, id.encode()),
         };
diff --git a/processor/src/networks/monero.rs b/processor/src/networks/monero.rs
index 5bedf5ef..f919b195 100644
--- a/processor/src/networks/monero.rs
+++ b/processor/src/networks/monero.rs
@@ -226,7 +226,7 @@ impl Monero {
       // This isn't entirely accurate as Bulletproof TXs will have a higher weight than their
       // serialization length
       // It's likely 'good enough'
-      // TODO: Improve
+      // TODO2: Improve
       fees.push(tx.rct_signatures.base.fee / u64::try_from(tx.serialize().len()).unwrap());
     }
     fees.sort();
diff --git a/processor/src/substrate_signer.rs b/processor/src/substrate_signer.rs
index f46fb7fe..2a93f42b 100644
--- a/processor/src/substrate_signer.rs
+++ b/processor/src/substrate_signer.rs
@@ -3,7 +3,6 @@ use std::collections::{VecDeque, HashMap};
 
 use rand_core::OsRng;
 
-use transcript::{Transcript, RecommendedTranscript};
 use ciphersuite::group::GroupEncoding;
 use frost::{
   curve::Ristretto,
@@ -24,20 +23,12 @@ use serai_client::{
   in_instructions::primitives::{Batch, SignedBatch, batch_message},
 };
 
-use messages::{sign::SignId, coordinator::*};
+use messages::coordinator::*;
 use crate::{Get, DbTxn, Db};
 
 // Generate an ID unique to a Batch
-// TODO: Fork SignId to BatchSignId in order to just use the 5-byte encoding, not the hash of the
-// 5-byte encoding
-fn sign_id(network: NetworkId, id: u32) -> [u8; 32] {
-  let mut transcript = RecommendedTranscript::new(b"Serai Processor Batch Sign ID");
-  transcript.append_message(b"network", network.encode());
-  transcript.append_message(b"id", id.to_le_bytes());
-
-  let mut res = [0; 32];
-  res.copy_from_slice(&transcript.challenge(b"id")[.. 32]);
-  res
+fn batch_sign_id(network: NetworkId, id: u32) -> [u8; 5] {
+  (network, id).encode().try_into().unwrap()
 }
 
 #[derive(Debug)]
@@ -53,23 +44,23 @@ impl<D: Db> SubstrateSignerDb<D> {
     D::key(b"SUBSTRATE_SIGNER", dst, key)
   }
 
-  fn completed_key(id: [u8; 32]) -> Vec<u8> {
+  fn completed_key(id: [u8; 5]) -> Vec<u8> {
     Self::sign_key(b"completed", id)
   }
-  fn complete(txn: &mut D::Transaction<'_>, id: [u8; 32]) {
+  fn complete(txn: &mut D::Transaction<'_>, id: [u8; 5]) {
     txn.put(Self::completed_key(id), []);
   }
-  fn completed<G: Get>(getter: &G, id: [u8; 32]) -> bool {
+  fn completed<G: Get>(getter: &G, id: [u8; 5]) -> bool {
     getter.get(Self::completed_key(id)).is_some()
   }
 
-  fn attempt_key(id: &SignId) -> Vec<u8> {
+  fn attempt_key(id: &BatchSignId) -> Vec<u8> {
     Self::sign_key(b"attempt", id.encode())
   }
-  fn attempt(txn: &mut D::Transaction<'_>, id: &SignId) {
+  fn attempt(txn: &mut D::Transaction<'_>, id: &BatchSignId) {
     txn.put(Self::attempt_key(id), []);
   }
-  fn has_attempt<G: Get>(getter: &G, id: &SignId) -> bool {
+  fn has_attempt<G: Get>(getter: &G, id: &BatchSignId) -> bool {
     getter.get(Self::attempt_key(id)).is_some()
   }
 
@@ -89,14 +80,14 @@ pub struct SubstrateSigner<D: Db> {
   network: NetworkId,
   keys: Vec<ThresholdKeys<Ristretto>>,
 
-  signable: HashMap<[u8; 32], Batch>,
-  attempt: HashMap<[u8; 32], u32>,
+  signable: HashMap<[u8; 5], Batch>,
+  attempt: HashMap<[u8; 5], u32>,
   #[allow(clippy::type_complexity)]
   preprocessing:
-    HashMap<[u8; 32], (Vec<AlgorithmSignMachine<Ristretto, Schnorrkel>>, Vec<Preprocess>)>,
+    HashMap<[u8; 5], (Vec<AlgorithmSignMachine<Ristretto, Schnorrkel>>, Vec<Preprocess>)>,
   #[allow(clippy::type_complexity)]
   signing:
-    HashMap<[u8; 32], (AlgorithmSignatureMachine<Ristretto, Schnorrkel>, Vec<SignatureShare>)>,
+    HashMap<[u8; 5], (AlgorithmSignatureMachine<Ristretto, Schnorrkel>, Vec<SignatureShare>)>,
 
   pub events: VecDeque<SubstrateSignerEvent>,
 }
@@ -129,7 +120,7 @@ impl<D: Db> SubstrateSigner<D> {
     }
   }
 
-  fn verify_id(&self, id: &SignId) -> Result<(), ()> {
+  fn verify_id(&self, id: &BatchSignId) -> Result<(), ()> {
     // Check the attempt lines up
     match self.attempt.get(&id.id) {
       // If we don't have an attempt logged, it's because the coordinator is faulty OR because we
@@ -155,7 +146,7 @@ impl<D: Db> SubstrateSigner<D> {
     Ok(())
   }
 
-  async fn attempt(&mut self, txn: &mut D::Transaction<'_>, id: [u8; 32], attempt: u32) {
+  async fn attempt(&mut self, txn: &mut D::Transaction<'_>, id: [u8; 5], attempt: u32) {
     // See above commentary for why this doesn't emit SignedBatch
     if SubstrateSignerDb::<D>::completed(txn, id) {
       return;
@@ -189,7 +180,7 @@ impl<D: Db> SubstrateSigner<D> {
     // Update the attempt number
     self.attempt.insert(id, attempt);
 
-    let id = SignId { key: self.keys[0].group_key().to_bytes().to_vec(), id, attempt };
+    let id = BatchSignId { key: self.keys[0].group_key().to_bytes(), id, attempt };
     info!("signing batch {} #{}", hex::encode(id.id), id.attempt);
 
     // If we reboot mid-sign, the current design has us abort all signs and wait for latter
@@ -241,7 +232,7 @@ impl<D: Db> SubstrateSigner<D> {
 
   pub async fn sign(&mut self, txn: &mut D::Transaction<'_>, batch: Batch) {
     debug_assert_eq!(self.network, batch.network);
-    let id = sign_id(batch.network, batch.id);
+    let id = batch_sign_id(batch.network, batch.id);
     if SubstrateSignerDb::<D>::completed(txn, id) {
       debug!("Sign batch order for ID we've already completed signing");
       // See batch_signed for commentary on why this simply returns
@@ -400,7 +391,7 @@ impl<D: Db> SubstrateSigner<D> {
     // block behind it, which will trigger starting the Batch
     // TODO: There is a race condition between the Scanner recognizing the block and the Batch
     // having signing started
-    let sign_id = sign_id(self.network, id);
+    let sign_id = batch_sign_id(self.network, id);
 
     // Stop trying to sign for this batch
     SubstrateSignerDb::<D>::complete(txn, sign_id);
diff --git a/processor/src/tests/substrate_signer.rs b/processor/src/tests/substrate_signer.rs
index 9dd96791..418a5a90 100644
--- a/processor/src/tests/substrate_signer.rs
+++ b/processor/src/tests/substrate_signer.rs
@@ -13,9 +13,10 @@ use sp_application_crypto::{RuntimePublic, sr25519::Public};
 
 use serai_db::{DbTxn, Db, MemDb};
 
+use scale::Encode;
 use serai_client::{primitives::*, in_instructions::primitives::*};
 
-use messages::{sign::SignId, coordinator::*};
+use messages::coordinator::*;
 use crate::substrate_signer::{SubstrateSignerEvent, SubstrateSigner};
 
 #[tokio::test]
@@ -26,11 +27,6 @@ async fn test_substrate_signer() {
 
   let id: u32 = 5;
   let block = BlockHash([0xaa; 32]);
-  let mut actual_id = SignId {
-    key: keys.values().next().unwrap().group_key().to_bytes().to_vec(),
-    id: [0; 32],
-    attempt: 0,
-  };
 
   let batch = Batch {
     network: NetworkId::Monero,
@@ -48,6 +44,12 @@ async fn test_substrate_signer() {
     ],
   };
 
+  let actual_id = BatchSignId {
+    key: keys.values().next().unwrap().group_key().to_bytes(),
+    id: (batch.network, batch.id).encode().try_into().unwrap(),
+    attempt: 0,
+  };
+
   let mut signers = HashMap::new();
   let mut dbs = HashMap::new();
   let mut t = 0;
@@ -88,9 +90,6 @@ async fn test_substrate_signer() {
       preprocesses: mut these_preprocesses,
     }) = signers.get_mut(&i).unwrap().events.pop_front().unwrap()
     {
-      if actual_id.id == [0; 32] {
-        actual_id.id = id.id;
-      }
       assert_eq!(id, actual_id);
       assert_eq!(batch_block, block);
       assert_eq!(these_preprocesses.len(), 1);
diff --git a/tests/coordinator/src/tests/batch.rs b/tests/coordinator/src/tests/batch.rs
index ac7a6165..49ceb20b 100644
--- a/tests/coordinator/src/tests/batch.rs
+++ b/tests/coordinator/src/tests/batch.rs
@@ -23,7 +23,7 @@ use serai_client::{
     InInstructionsEvent,
   },
 };
-use messages::{sign::SignId, SubstrateContext, CoordinatorMessage};
+use messages::{coordinator::BatchSignId, SubstrateContext, CoordinatorMessage};
 
 use crate::{*, tests::*};
 
@@ -33,10 +33,10 @@ pub async fn batch(
   substrate_key: &Zeroizing<<Ristretto as Ciphersuite>::F>,
   batch: Batch,
 ) -> u64 {
-  let mut id = [0; 32];
+  let mut id = [0; 5];
   OsRng.fill_bytes(&mut id);
-  let id = SignId {
-    key: (<Ristretto as Ciphersuite>::generator() * **substrate_key).to_bytes().to_vec(),
+  let id = BatchSignId {
+    key: (<Ristretto as Ciphersuite>::generator() * **substrate_key).to_bytes(),
     id,
     attempt: 0,
   };
diff --git a/tests/coordinator/src/tests/key_gen.rs b/tests/coordinator/src/tests/key_gen.rs
index ed18258c..122c6c7f 100644
--- a/tests/coordinator/src/tests/key_gen.rs
+++ b/tests/coordinator/src/tests/key_gen.rs
@@ -89,7 +89,7 @@ pub async fn key_gen<C: Ciphersuite>(
         (
           participant_is[usize::from(l)],
           vec![
-            u8::try_from(u16::try_from(participant_is[i]).unwrap()).unwrap(),
+            u8::try_from(u16::from(participant_is[i])).unwrap(),
             u8::try_from(u16::from(participant_is[usize::from(l)])).unwrap(),
           ],
         )
diff --git a/tests/processor/src/networks.rs b/tests/processor/src/networks.rs
index 755f546d..9db4fb1d 100644
--- a/tests/processor/src/networks.rs
+++ b/tests/processor/src/networks.rs
@@ -402,8 +402,7 @@ impl Wallet {
             view_pair.address(Network::Mainnet, AddressSpec::Standard),
           )
           .unwrap()
-          .try_into()
-          .unwrap(),
+          .into(),
         )
         .unwrap()
       }
diff --git a/tests/processor/src/tests/batch.rs b/tests/processor/src/tests/batch.rs
index d41b767a..cdc09402 100644
--- a/tests/processor/src/tests/batch.rs
+++ b/tests/processor/src/tests/batch.rs
@@ -5,8 +5,9 @@ use std::{
 
 use dkg::{Participant, tests::clone_without};
 
-use messages::{coordinator::PlanMeta, sign::SignId, SubstrateContext};
+use messages::{coordinator::*, SubstrateContext};
 
+use scale::Encode;
 use serai_client::{
   primitives::{
     BlockHash, Amount, Balance, crypto::RuntimePublic, PublicKey, SeraiAddress, NetworkId,
@@ -25,8 +26,13 @@ pub(crate) async fn recv_batch_preprocesses(
   substrate_key: &[u8; 32],
   batch: &Batch,
   attempt: u32,
-) -> (SignId, HashMap<Participant, Vec<u8>>) {
-  let mut id = None;
+) -> (BatchSignId, HashMap<Participant, Vec<u8>>) {
+  let id = BatchSignId {
+    key: *substrate_key,
+    id: (batch.network, batch.id).encode().try_into().unwrap(),
+    attempt,
+  };
+
   let mut block = None;
   let mut preprocesses = HashMap::new();
   for (i, coordinator) in coordinators.iter_mut().enumerate() {
@@ -51,13 +57,10 @@ pub(crate) async fn recv_batch_preprocesses(
           preprocesses: mut these_preprocesses,
         },
       ) => {
-        if id.is_none() {
-          assert_eq!(&this_id.key, substrate_key);
-          assert_eq!(this_id.attempt, attempt);
-          id = Some(this_id.clone());
+        assert_eq!(this_id, id);
+        if block.is_none() {
           block = Some(this_block);
         }
-        assert_eq!(&this_id, id.as_ref().unwrap());
         assert_eq!(&this_block, block.as_ref().unwrap());
 
         assert_eq!(these_preprocesses.len(), 1);
@@ -77,13 +80,13 @@ pub(crate) async fn recv_batch_preprocesses(
     );
   }
 
-  (id.unwrap(), preprocesses)
+  (id, preprocesses)
 }
 
 pub(crate) async fn sign_batch(
   coordinators: &mut [Coordinator],
   key: [u8; 32],
-  id: SignId,
+  id: BatchSignId,
   preprocesses: HashMap<Participant, Vec<u8>>,
 ) -> SignedBatch {
   assert_eq!(preprocesses.len(), THRESHOLD);