fix(crypto): handle 1-of-N Shamir split when ordinary_count=1

server/crates/arbiter-server/tests/vault/lifecycle.rs

@@ -3,14 +3,17 @@ use arbiter_crypto::safecell::{SafeCell, SafeCellHandle as _};
 use arbiter_server::{
     actors::{
         GlobalActors,
-        vault::{Error, Vault},
-        vault_coordinator::{Error as CoordinatorError, StartBootstrap, VaultCoordinator},
+        vault::{Error, GetState, Vault, VaultState},
+        vault_coordinator::{
+            ContributeBootstrap, ContributeRecoveryBootstrap, ContributeRecoveryUnseal,
+            Error as CoordinatorError, StartBootstrap, VaultCoordinator,
+        },
     },
     crypto::{KeyCell, encryption::v1::{Nonce, ROOT_KEY_TAG}},
     db::{self, models, schema},
 };
 
-use diesel::{QueryDsl, SelectableHelper};
+use diesel::{ExpressionMethods, QueryDsl, SelectableHelper, insert_into};
 use diesel_async::RunQueryDsl;
 use kameo::actor::Spawn as _;
 
@@ -167,3 +170,101 @@ async fn two_operator_vault_requires_recovery_share() {
         "expected TwoOperatorsRequireRecovery, got {err:?}"
     );
 }
+
+/// §3.4: Bootstrap with 1 ordinary + 1 recovery operator produces a valid 1-of-2 Shamir split.
+/// Both ordinary and recovery shares are stored; the vault can be unsealed with either one.
+#[tokio::test]
+#[test_log::test]
+async fn recovery_share_stored_and_used_for_unseal() {
+    let db = db::create_test_pool().await;
+    let bus = GlobalActors::spawn_message_bus();
+    let vault_ref = Vault::spawn(Vault::new(db.clone(), bus).await.unwrap());
+    let coordinator = VaultCoordinator::spawn(VaultCoordinator::new(db.clone(), vault_ref.clone()));
+
+    // Register one ordinary operator and one recovery operator in the DB
+    let ordinary_id: i32 = {
+        let mut conn = db.get().await.unwrap();
+        insert_into(schema::operator_identity::table)
+            .values(schema::operator_identity::public_key.eq(vec![1u8; 32]))
+            .returning(schema::operator_identity::id)
+            .get_result(&mut conn)
+            .await
+            .unwrap()
+    };
+    let recovery_id: i32 = {
+        let mut conn = db.get().await.unwrap();
+        insert_into(schema::recovery_operator_identity::table)
+            .values(schema::recovery_operator_identity::public_key.eq(vec![2u8; 32]))
+            .returning(schema::recovery_operator_identity::id)
+            .get_result(&mut conn)
+            .await
+            .unwrap()
+    };
+
+    // Declare committee: 1 ordinary + 1 recovery
+    coordinator
+        .ask(StartBootstrap {
+            operator_id: ordinary_id,
+            declared_count: 1,
+            recovery_count: 1,
+        })
+        .await
+        .unwrap();
+
+    // Recovery operator contributes first — bootstrap should not finalize yet
+    let done = coordinator
+        .ask(ContributeRecoveryBootstrap {
+            recovery_operator_id: recovery_id,
+            passphrase: SafeCell::new(b"recovery-pass".to_vec()),
+        })
+        .await
+        .unwrap();
+    assert!(!done, "should not finalize with only recovery passphrase");
+
+    // Ordinary operator contributes — now bootstrap finalizes
+    let done = coordinator
+        .ask(ContributeBootstrap {
+            operator_id: ordinary_id,
+            passphrase: SafeCell::new(b"ordinary-pass".to_vec()),
+        })
+        .await
+        .unwrap();
+    assert!(done, "should finalize once all contributors are in");
+
+    // After bootstrap, vault is Unsealed (seal key still in memory).
+    let state = vault_ref.ask(GetState {}).await.unwrap();
+    assert_eq!(state, VaultState::Unsealed);
+
+    // Verify recovery_operator row was created
+    let recovery_share_count: i64 = {
+        let mut conn = db.get().await.unwrap();
+        schema::recovery_operator::table
+            .count()
+            .get_result(&mut conn)
+            .await
+            .unwrap()
+    };
+    assert_eq!(recovery_share_count, 1);
+
+    // Simulate restart: drop vault and coordinator, create fresh vault (comes up Sealed).
+    drop(coordinator);
+    drop(vault_ref);
+    let bus2 = GlobalActors::spawn_message_bus();
+    let vault_ref2 = Vault::spawn(Vault::new(db.clone(), bus2).await.unwrap());
+    let state = vault_ref2.ask(GetState {}).await.unwrap();
+    assert_eq!(state, VaultState::Sealed);
+
+    // §3.5: Unseal using ONLY the recovery operator share (threshold = shamir_threshold(1) = 1).
+    let coordinator2 = VaultCoordinator::spawn(VaultCoordinator::new(db.clone(), vault_ref2.clone()));
+    let done = coordinator2
+        .ask(ContributeRecoveryUnseal {
+            recovery_operator_id: recovery_id,
+            passphrase: SafeCell::new(b"recovery-pass".to_vec()),
+        })
+        .await
+        .unwrap();
+    assert!(done, "recovery share alone should satisfy threshold");
+
+    let state = vault_ref2.ask(GetState {}).await.unwrap();
+    assert_eq!(state, VaultState::Unsealed);
+}