feat(server): implement KeyStorage and state machine lifecycle

server/crates/arbiter-server/migrations/2026-02-16-160000-0000_add_argon2_salt/down.sql

@@ -0,0 +1,2 @@
+-- Remove argon2_salt column
+ALTER TABLE aead_encrypted DROP COLUMN argon2_salt;

server/crates/arbiter-server/migrations/2026-02-16-160000-0000_add_argon2_salt/up.sql

@@ -0,0 +1,2 @@
+-- Add argon2_salt column to store password derivation salt
+ALTER TABLE aead_encrypted ADD COLUMN argon2_salt TEXT;

server/crates/arbiter-server/src/context.rs

@@ -8,9 +8,11 @@ use ed25519_dalek::VerifyingKey;
 use kameo::actor::{ActorRef, Spawn};
 use miette::Diagnostic;
 use rand::rngs::StdRng;
+use secrecy::{ExposeSecret, SecretBox};
 use smlang::statemachine;
 use thiserror::Error;
 use tokio::sync::{watch, RwLock};
+use zeroize::Zeroizing;
 
 use crate::{
     context::{
@@ -56,8 +58,66 @@ pub enum InitError {
     Io(#[from] std::io::Error),
 }
 
-// TODO: Placeholder for secure root key cell implementation
+#[derive(Error, Debug, Diagnostic)]
-pub struct KeyStorage;
+pub enum UnsealError {
+    #[error("Database error: {0}")]
+    #[diagnostic(code(arbiter_server::unseal::database_pool))]
+    Database(#[from] db::PoolError),
+
+    #[error("Query error: {0}")]
+    #[diagnostic(code(arbiter_server::unseal::database_query))]
+    Query(#[from] diesel::result::Error),
+
+    #[error("Decryption failed: {0}")]
+    #[diagnostic(code(arbiter_server::unseal::decryption))]
+    DecryptionFailed(#[from] crate::crypto::CryptoError),
+
+    #[error("Invalid state for unseal")]
+    #[diagnostic(code(arbiter_server::unseal::invalid_state))]
+    InvalidState,
+
+    #[error("Missing salt in database")]
+    #[diagnostic(code(arbiter_server::unseal::missing_salt))]
+    MissingSalt,
+
+    #[error("No root key configured in database")]
+    #[diagnostic(code(arbiter_server::unseal::no_root_key))]
+    NoRootKey,
+}
+
+#[derive(Error, Debug, Diagnostic)]
+pub enum SealError {
+    #[error("Invalid state for seal")]
+    #[diagnostic(code(arbiter_server::seal::invalid_state))]
+    InvalidState,
+}
+
+/// Secure in-memory storage for root encryption key
+///
+/// Uses `secrecy` crate for automatic zeroization on drop to prevent key material
+/// from remaining in memory after use. SecretBox provides heap-allocated secret
+/// storage that implements Send + Sync for safe use in async contexts.
+pub struct KeyStorage {
+    /// 32-byte root key protected by SecretBox
+    key: SecretBox<[u8; 32]>,
+}
+
+impl KeyStorage {
+    /// Create new KeyStorage from a 32-byte root key
+    pub fn new(key: [u8; 32]) -> Self {
+        Self {
+            key: SecretBox::new(Box::new(key)),
+        }
+    }
+
+    /// Access the key for cryptographic operations
+    pub fn key(&self) -> &[u8; 32] {
+        self.key.expose_secret()
+    }
+}
+
+// Drop автоматически реализован через secrecy::Zeroize
+// который зануляет память при освобождении
 
 statemachine! {
     name: Server,
@@ -69,14 +129,20 @@ statemachine! {
 }
 pub struct _Context;
 impl ServerStateMachineContext for _Context {
-    fn move_key(&mut self, _event_data: KeyStorage) -> Result<KeyStorage, ()> {
+    /// Move key from unseal event into Ready state
-        todo!()
+    fn move_key(&mut self, event_data: KeyStorage) -> Result<KeyStorage, ()> {
+        // Просто перемещаем KeyStorage из event в state
+        // Без клонирования - event data consumed
+        Ok(event_data)
     }
 
+    /// Securely dispose of key when sealing
     #[allow(missing_docs)]
     #[allow(clippy::unused_unit)]
     fn dispose_key(&mut self, _state_data: &KeyStorage) -> Result<(), ()> {
-        todo!()
+        // KeyStorage будет dropped после state transition
+        // secrecy::Zeroize зануляет память автоматически
+        Ok(())
     }
 }
 
@@ -200,4 +266,137 @@ impl ServerContext {
 
         Ok(Self(context))
     }
+
+    /// Unseal vault with password
+    pub async fn unseal(&self, password: &str) -> Result<(), UnsealError> {
+        use crate::crypto::root_key;
+        use diesel::QueryDsl as _;
+
+        // 1. Get root_key_id from settings
+        let mut conn = self.db.get().await?;
+
+        let settings: db::models::ArbiterSetting = schema::arbiter_settings::table
+            .first(&mut conn)
+            .await?;
+
+        let root_key_id = settings.root_key_id.ok_or(UnsealError::NoRootKey)?;
+
+        // 2. Load encrypted root key
+        let encrypted: db::models::AeadEncrypted = schema::aead_encrypted::table
+            .find(root_key_id)
+            .first(&mut conn)
+            .await?;
+
+        let salt = encrypted
+            .argon2_salt
+            .as_ref()
+            .ok_or(UnsealError::MissingSalt)?;
+
+        drop(conn);
+
+        // 3. Decrypt root key using password
+        let root_key = root_key::decrypt_root_key(&encrypted, password, salt)
+            .map_err(UnsealError::DecryptionFailed)?;
+
+        // 4. Create secure storage
+        let key_storage = KeyStorage::new(root_key);
+
+        // 5. Transition state machine
+        let mut state = self.state.write().await;
+        state
+            .process_event(ServerEvents::Unsealed(key_storage))
+            .map_err(|_| UnsealError::InvalidState)?;
+
+        Ok(())
+    }
+
+    /// Seal the server (lock the key)
+    pub async fn seal(&self) -> Result<(), SealError> {
+        let mut state = self.state.write().await;
+        state
+            .process_event(ServerEvents::Sealed)
+            .map_err(|_| SealError::InvalidState)?;
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_keystorage_creation() {
+        let key = [42u8; 32];
+        let storage = KeyStorage::new(key);
+        assert_eq!(storage.key()[0], 42);
+        assert_eq!(storage.key().len(), 32);
+    }
+
+    #[test]
+    fn test_keystorage_zeroization() {
+        let key = [99u8; 32];
+        {
+            let _storage = KeyStorage::new(key);
+            // storage будет dropped здесь
+        }
+        // После drop SecretBox должен зануляеть память
+        // Это проверяется автоматически через secrecy::Zeroize
+    }
+
+    #[test]
+    fn test_state_machine_transitions() {
+        let mut state = ServerStateMachine::new(_Context);
+
+        // Начальное состояние
+        assert!(matches!(state.state(), &ServerStates::NotBootstrapped));
+
+        // Bootstrapped transition
+        state.process_event(ServerEvents::Bootstrapped).unwrap();
+        assert!(matches!(state.state(), &ServerStates::Sealed));
+
+        // Unsealed transition
+        let key_storage = KeyStorage::new([1u8; 32]);
+        state
+            .process_event(ServerEvents::Unsealed(key_storage))
+            .unwrap();
+        assert!(matches!(state.state(), &ServerStates::Ready(_)));
+
+        // Sealed transition
+        state.process_event(ServerEvents::Sealed).unwrap();
+        assert!(matches!(state.state(), &ServerStates::Sealed));
+    }
+
+    #[test]
+    fn test_move_key_callback() {
+        let mut ctx = _Context;
+        let key_storage = KeyStorage::new([7u8; 32]);
+        let result = ctx.move_key(key_storage);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap().key()[0], 7);
+    }
+
+    #[test]
+    fn test_dispose_key_callback() {
+        let mut ctx = _Context;
+        let key_storage = KeyStorage::new([13u8; 32]);
+        let result = ctx.dispose_key(&key_storage);
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn test_invalid_state_transitions() {
+        let mut state = ServerStateMachine::new(_Context);
+
+        // Попытка unseal без bootstrap
+        let key_storage = KeyStorage::new([1u8; 32]);
+        let result = state.process_event(ServerEvents::Unsealed(key_storage));
+        assert!(result.is_err());
+
+        // Правильный путь
+        state.process_event(ServerEvents::Bootstrapped).unwrap();
+
+        // Попытка повторного bootstrap
+        let result = state.process_event(ServerEvents::Bootstrapped);
+        assert!(result.is_err());
+    }
 }

server/crates/arbiter-server/src/crypto/root_key.rs

@@ -39,6 +39,7 @@ pub fn encrypt_root_key(
         ciphertext,
         tag,
         schema_version: 1, // Current version
+        argon2_salt: Some(salt.clone()),
     };
 
     Ok((aead_encrypted, salt))

server/crates/arbiter-server/src/db/models.rs

@@ -9,14 +9,15 @@ pub mod types {
     pub struct SqliteTimestamp(DateTime<Utc>);
 }
 
-#[derive(Queryable, Debug, Insertable)]
+#[derive(Queryable, Selectable, Debug, Insertable)]
 #[diesel(table_name = aead_encrypted, check_for_backend(Sqlite))]
 pub struct AeadEncrypted {
     pub id: i32,
+    pub current_nonce: i32,
     pub ciphertext: Vec<u8>,
     pub tag: Vec<u8>,
-    pub current_nonce: i32,
     pub schema_version: i32,
+    pub argon2_salt: Option<String>,
 }
 
 #[derive(Queryable, Debug, Insertable)]

server/crates/arbiter-server/src/db/schema.rs

@@ -7,6 +7,7 @@ diesel::table! {
         ciphertext -> Binary,
         tag -> Binary,
         schema_version -> Integer,
+        argon2_salt -> Nullable<Text>,
     }
 }