Support varying t and allowed_delta across epochs

crates/e2e-tests/src/e2e_flow.rs

@@ -1345,6 +1345,131 @@ mod tests {
         Ok(())
     }
 
+    #[tokio::test(flavor = "multi_thread")]
+    async fn test_varying_t_and_allowed_delta_across_epochs() -> Result<()> {
+        init_test_logging();
+
+        let mut networks = TestNetworksBuilder::new().with_nodes(4).build().await?;
+
+        use hashi::onchain::types::DEFAULT_MPC_THRESHOLD_BASIS_POINTS;
+        use hashi::onchain::types::DEFAULT_MPC_WEIGHT_REDUCTION_ALLOWED_DELTA;
+
+        // Wait for DKG (epoch 1 committee created with defaults).
+        let nodes = networks.hashi_network.nodes();
+        let futs: Vec<_> = nodes
+            .iter()
+            .map(|n| n.wait_for_mpc_key(Duration::from_secs(120)))
+            .collect();
+        for (i, r) in futures::future::join_all(futs)
+            .await
+            .into_iter()
+            .enumerate()
+        {
+            r.unwrap_or_else(|e| panic!("Node {i} DKG failed: {e}"));
+        }
+
+        let initial_epoch = nodes[0].current_epoch().unwrap();
+        let pk_before = nodes[0].hashi().mpc_handle().unwrap().public_key().unwrap();
+
+        // Verify epoch 1 committee has defaults.
+        let epoch1_committee = nodes[0]
+            .hashi()
+            .onchain_state()
+            .current_committee()
+            .unwrap();
+        assert_eq!(
+            epoch1_committee.mpc_threshold_basis_points(),
+            DEFAULT_MPC_THRESHOLD_BASIS_POINTS
+        );
+        assert_eq!(
+            epoch1_committee.mpc_weight_reduction_allowed_delta(),
+            DEFAULT_MPC_WEIGHT_REDUCTION_ALLOWED_DELTA
+        );
+
+        // Change config between epochs.
+        let new_threshold: u64 = 5000;
+        let new_delta: u64 = 1200;
+        crate::apply_onchain_config_overrides(
+            &mut networks,
+            &[
+                (
+                    "mpc_threshold_basis_points".into(),
+                    hashi_types::move_types::ConfigValue::U64(new_threshold),
+                ),
+                (
+                    "mpc_weight_reduction_allowed_delta".into(),
+                    hashi_types::move_types::ConfigValue::U64(new_delta),
+                ),
+            ],
+        )
+        .await?;
+
+        // Force key rotation → epoch 2 committee created with new config.
+        let target_epoch = initial_epoch + 1;
+        networks.sui_network.force_close_epoch().await?;
+        let futs: Vec<_> = networks
+            .hashi_network()
+            .nodes()
+            .iter()
+            .map(|n| n.wait_for_epoch(target_epoch, Duration::from_secs(480)))
+            .collect();
+        for (i, r) in futures::future::join_all(futs)
+            .await
+            .into_iter()
+            .enumerate()
+        {
+            r.unwrap_or_else(|e| panic!("Node {i} failed to reach epoch {target_epoch}: {e}"));
+        }
+
+        // Verify key rotation succeeded: all nodes agree and key is preserved.
+        let nodes = networks.hashi_network().nodes();
+        let pk_after = nodes[0].hashi().mpc_handle().unwrap().public_key().unwrap();
+        assert_eq!(
+            pk_before, pk_after,
+            "MPC public key changed during rotation"
+        );
+        for (i, node) in nodes.iter().enumerate().skip(1) {
+            let pk = node.hashi().mpc_handle().unwrap().public_key().unwrap();
+            assert_eq!(
+                pk, pk_after,
+                "Node {i} MPC key differs from node 0 after rotation"
+            );
+        }
+
+        // Epoch 1 committee retains original defaults.
+        let state = networks.hashi_network.nodes()[0].hashi().onchain_state();
+        let committees = {
+            let s = state.state();
+            s.hashi().committees.committees().clone()
+        };
+        let epoch1 = committees.get(&initial_epoch).expect("epoch 1 committee");
+        assert_eq!(
+            epoch1.mpc_threshold_basis_points(),
+            DEFAULT_MPC_THRESHOLD_BASIS_POINTS,
+            "epoch {initial_epoch} committee should retain original threshold_basis_points"
+        );
+        assert_eq!(
+            epoch1.mpc_weight_reduction_allowed_delta(),
+            DEFAULT_MPC_WEIGHT_REDUCTION_ALLOWED_DELTA,
+            "epoch {initial_epoch} committee should retain original allowed_delta"
+        );
+
+        // Epoch 2 committee has new values.
+        let epoch2 = committees.get(&target_epoch).expect("epoch 2 committee");
+        assert_eq!(
+            epoch2.mpc_threshold_basis_points(),
+            new_threshold as u16,
+            "epoch {target_epoch} committee should have updated threshold_basis_points"
+        );
+        assert_eq!(
+            epoch2.mpc_weight_reduction_allowed_delta(),
+            new_delta as u16,
+            "epoch {target_epoch} committee should have updated allowed_delta"
+        );
+
+        Ok(())
+    }
+
     /// Verify that a withdrawal can spend a change output whose producing
     /// transaction is mined on Bitcoin but not yet confirmed on Sui. The
     /// actual Bitcoin confirmation count must be queried from the node

crates/e2e-tests/src/lib.rs

@@ -265,7 +265,7 @@ impl TestNetworksBuilder {
 /// Waits for DKG to complete first so the committee is ready to vote.
 /// All nodes vote on every proposal, ensuring quorum is always reached
 /// regardless of the number of nodes or their weight distribution.
-async fn apply_onchain_config_overrides(
+pub(crate) async fn apply_onchain_config_overrides(
     networks: &mut TestNetworks,
     overrides: &[(String, hashi_types::move_types::ConfigValue)],
 ) -> Result<()> {

crates/hashi-types/proto/sui/hashi/v1alpha/signature.proto

@@ -6,6 +6,8 @@ message Committee {
   optional uint64 epoch = 1;
   repeated CommitteeMember members = 2;
   optional uint64 total_weight = 3;
+  optional uint64 mpc_threshold_basis_points = 4;
+  optional uint64 mpc_weight_reduction_allowed_delta = 5;
 }
 
 message CommitteeMember {

crates/hashi-types/src/committee.rs

@@ -21,6 +21,14 @@ use serde::Serialize;
 use sui_crypto::SignatureError;
 use sui_sdk_types::Address;
 
+/// Default MPC threshold in basis points. Mirrors `DEFAULT_THRESHOLD_BASIS_POINTS` in
+/// `mpc_config.move`.
+pub const DEFAULT_MPC_THRESHOLD_BASIS_POINTS: u16 = 3333;
+
+/// Default allowed delta for weight reduction. Mirrors `DEFAULT_WEIGHT_REDUCTION_ALLOWED_DELTA` in
+/// `mpc_config.move`.
+pub const DEFAULT_MPC_WEIGHT_REDUCTION_ALLOWED_DELTA: u16 = 800;
+
 // TODO: Read threshold from on-chain config once it is made configurable.
 const THRESHOLD_NUMERATOR: u64 = 2;
 const THRESHOLD_DENOMINATOR: u64 = 3;
@@ -85,6 +93,8 @@ pub struct Committee {
     members: Vec<CommitteeMember>,
     address_to_index: HashMap<Address, usize>,
     total_weight: u64,
+    mpc_threshold_basis_points: u16,
+    mpc_weight_reduction_allowed_delta: u16,
 }
 
 #[derive(Clone, PartialEq)]
@@ -147,7 +157,12 @@ impl MemberSignature {
 }
 
 impl Committee {
-    pub fn new(members: Vec<CommitteeMember>, epoch: u64) -> Self {
+    pub fn new(
+        members: Vec<CommitteeMember>,
+        epoch: u64,
+        mpc_threshold_basis_points: u16,
+        mpc_weight_reduction_allowed_delta: u16,
+    ) -> Self {
         let total_weight = members.iter().map(|member| member.weight).sum();
         let address_to_index = members
             .iter()
@@ -159,6 +174,8 @@ impl Committee {
             members,
             address_to_index,
             total_weight,
+            mpc_threshold_basis_points,
+            mpc_weight_reduction_allowed_delta,
         }
     }
 
@@ -175,6 +192,14 @@ impl Committee {
         self.total_weight
     }
 
+    pub fn mpc_threshold_basis_points(&self) -> u16 {
+        self.mpc_threshold_basis_points
+    }
+
+    pub fn mpc_weight_reduction_allowed_delta(&self) -> u16 {
+        self.mpc_weight_reduction_allowed_delta
+    }
+
     fn member(&self, address: &Address) -> Result<&CommitteeMember, SignatureError> {
         let index = self
             .address_to_index
@@ -662,6 +687,9 @@ mod test {
     use fastcrypto::groups::FiatShamirChallenge;
     use fastcrypto::groups::bls12381::Scalar;
     use fastcrypto::serde_helpers::ToFromByteArray;
+
+    const TEST_THRESHOLD_BASIS_POINTS: u16 = 3333;
+    const TEST_ALLOWED_DELTA: u16 = 0;
     use test_strategy::proptest;
 
     impl proptest::arbitrary::Arbitrary for Bls12381PrivateKey {
@@ -719,7 +747,12 @@ mod test {
                 weight: 1,
             })
             .collect();
-        let committee = Committee::new(members, epoch);
+        let committee = Committee::new(
+            members,
+            epoch,
+            TEST_THRESHOLD_BASIS_POINTS,
+            TEST_ALLOWED_DELTA,
+        );
 
         let mut aggregator = BlsSignatureAggregator::new(&committee, message.clone());
 
@@ -816,7 +849,12 @@ mod test {
                 weight: 1,
             })
             .collect();
-        let committee = Committee::new(members, epoch);
+        let committee = Committee::new(
+            members,
+            epoch,
+            TEST_THRESHOLD_BASIS_POINTS,
+            TEST_ALLOWED_DELTA,
+        );
 
         let mut aggregator = BlsSignatureAggregator::new(&committee, message.clone());
 
@@ -858,6 +896,8 @@ mod test {
                 })
                 .collect(),
             999, // Different epoch
+            TEST_THRESHOLD_BASIS_POINTS,
+            TEST_ALLOWED_DELTA,
         );
         assert!(
             certificate
@@ -887,7 +927,12 @@ mod test {
                 weight: 2500, // committee weight
             })
             .collect();
-        let committee = Committee::new(members, epoch);
+        let committee = Committee::new(
+            members,
+            epoch,
+            TEST_THRESHOLD_BASIS_POINTS,
+            TEST_ALLOWED_DELTA,
+        );
 
         // Reduced weights: different from committee weights
         let reduced_weights: HashMap<Address, u16> =
@@ -970,7 +1015,12 @@ mod test {
                 weight: 1,
             })
             .collect();
-        let committee = Committee::new(members, epoch);
+        let committee = Committee::new(
+            members,
+            epoch,
+            TEST_THRESHOLD_BASIS_POINTS,
+            TEST_ALLOWED_DELTA,
+        );
 
         // Create a certificate via aggregator
         let mut aggregator = BlsSignatureAggregator::new(&committee, message.clone());

crates/hashi-types/src/guardian/proto_conversions.rs

@@ -54,6 +54,9 @@ use hpke::Serializable;
 use std::num::NonZeroU16;
 use std::str::FromStr;
 
+use crate::committee::DEFAULT_MPC_THRESHOLD_BASIS_POINTS;
+use crate::committee::DEFAULT_MPC_WEIGHT_REDUCTION_ALLOWED_DELTA;
+
 // --------------------------------------------
 //      Proto -> Domain (deserialization)
 // --------------------------------------------
@@ -666,7 +669,20 @@ fn pb_to_hashi_committee(c: pb::Committee) -> GuardianResult<HashiCommittee> {
 
     let total_weight = c.total_weight.ok_or_else(|| missing("total_weight"))?;
 
-    let committee = HashiCommittee::new(members, epoch);
+    let threshold_basis_points = c
+        .mpc_threshold_basis_points
+        .map(|v| v as u16)
+        .unwrap_or(DEFAULT_MPC_THRESHOLD_BASIS_POINTS);
+    let weight_reduction_allowed_delta = c
+        .mpc_weight_reduction_allowed_delta
+        .map(|v| v as u16)
+        .unwrap_or(DEFAULT_MPC_WEIGHT_REDUCTION_ALLOWED_DELTA);
+    let committee = HashiCommittee::new(
+        members,
+        epoch,
+        threshold_basis_points,
+        weight_reduction_allowed_delta,
+    );
 
     if committee.total_weight() != total_weight {
         return Err(InvalidInputs(format!(
@@ -687,6 +703,8 @@ fn hashi_committee_to_pb(c: HashiCommittee) -> pb::Committee {
             .map(|m| hashi_committee_member_to_pb(m.clone()))
             .collect(),
         total_weight: Some(c.total_weight()),
+        mpc_threshold_basis_points: Some(c.mpc_threshold_basis_points() as u64),
+        mpc_weight_reduction_allowed_delta: Some(c.mpc_weight_reduction_allowed_delta() as u64),
     }
 }
 

crates/hashi-types/src/guardian/test_utils.rs

@@ -46,6 +46,10 @@ use hpke::Deserializable;
 use std::num::NonZeroU16;
 use sui_sdk_types::Address as SuiAddress;
 use sui_sdk_types::bcs::FromBcs;
+
+use crate::committee::DEFAULT_MPC_THRESHOLD_BASIS_POINTS;
+use crate::committee::DEFAULT_MPC_WEIGHT_REDUCTION_ALLOWED_DELTA;
+
 // -------------------------------
 // Shared deterministic test values
 // -------------------------------
@@ -185,7 +189,12 @@ fn mock_committee_member() -> HashiCommitteeMember {
 }
 
 fn mock_committee_with_one_member(epoch: u64) -> HashiCommittee {
-    HashiCommittee::new(vec![mock_committee_member()], epoch)
+    HashiCommittee::new(
+        vec![mock_committee_member()],
+        epoch,
+        DEFAULT_MPC_THRESHOLD_BASIS_POINTS,
+        DEFAULT_MPC_WEIGHT_REDUCTION_ALLOWED_DELTA,
+    )
 }
 
 impl ProvisionerInitState {

crates/hashi-types/src/move_types/mod.rs

@@ -156,6 +156,8 @@ pub struct Committee {
     pub members: Vec<CommitteeMember>,
     /// Total voting weight of the committee.
     pub total_weight: u64,
+    pub mpc_threshold_basis_points: u64,
+    pub mpc_weight_reduction_allowed_delta: u64,
 }
 
 /// Rust version of the Move hashi::config::Config type.
@@ -1101,6 +1103,8 @@ impl From<&crate::committee::Committee> for Committee {
             epoch: c.epoch(),
             members: c.members().iter().map(Into::into).collect(),
             total_weight: c.total_weight(),
+            mpc_threshold_basis_points: c.mpc_threshold_basis_points() as u64,
+            mpc_weight_reduction_allowed_delta: c.mpc_weight_reduction_allowed_delta() as u64,
         }
     }
 }
@@ -1114,6 +1118,13 @@ impl TryFrom<Committee> for crate::committee::Committee {
             .into_iter()
             .map(crate::committee::CommitteeMember::try_from)
             .collect::<Result<Vec<_>, _>>()?;
-        Ok(crate::committee::Committee::new(members, c.epoch))
+        Ok(crate::committee::Committee::new(
+            members,
+            c.epoch,
+            u16::try_from(c.mpc_threshold_basis_points)
+                .expect("mpc_threshold_basis_points exceeds u16::MAX"),
+            u16::try_from(c.mpc_weight_reduction_allowed_delta)
+                .expect("mpc_weight_reduction_allowed_delta exceeds u16::MAX"),
+        ))
     }
 }

crates/hashi-types/src/proto/generated/sui.hashi.v1alpha.rs

@@ -2822,6 +2822,10 @@ pub struct Committee {
     pub members: ::prost::alloc::vec::Vec<CommitteeMember>,
     #[prost(uint64, optional, tag = "3")]
     pub total_weight: ::core::option::Option<u64>,
+    #[prost(uint64, optional, tag = "4")]
+    pub mpc_threshold_basis_points: ::core::option::Option<u64>,
+    #[prost(uint64, optional, tag = "5")]
+    pub mpc_weight_reduction_allowed_delta: ::core::option::Option<u64>,
 }
 #[derive(Clone, PartialEq, Eq, Hash, ::prost::Message)]
 pub struct CommitteeMember {