implementations

README.md

@@ -22,6 +22,7 @@ A decentralized health credential platform built on the Stellar Soroban Smart Co
 - **Batch Verification**: Verify multiple credentials simultaneously for venues and organizations
 - **Health Authority Integration**: Integration with certified health authorities for credential issuance
 - **Cross-Border Recognition**: Standardized format for international travel and compliance
+- **Robust Contract Upgrades**: Secure upgrade mechanism with timelock, proxy pattern, and state consistency validation
 
 ## 🏗️ Architecture
 
@@ -51,6 +52,15 @@ A decentralized health credential platform built on the Stellar Soroban Smart Co
 - Stores health authority public keys and signatures
 - Enables credential authority verification
 
+#### Upgrade Mechanism
+- **Proxy Pattern**: Seamless contract upgrades without data loss
+- **Timelock Security**: 24-hour delay between scheduling and executing upgrades
+- **Migration Registry**: Tracks all migrations with version, timestamp, and success status
+- **State Consistency**: Validates storage integrity before upgrades
+- **Access Control**: Admin-only upgrade functions with dual authorization for admin transfer
+- **Emergency Pause**: Ability to temporarily disable upgrades for critical situations
+- **Version Tracking**: Comprehensive version management with rollback prevention
+
 ### Off-Chain Components
 
 #### Backend (NestJS)
@@ -293,7 +303,108 @@ NEXT_PUBLIC_API_URL=http://localhost:3001/api/v1
 5. Click "Share Credential"
 6. The recipient will receive access for the specified duration
 
-## 🔧 API Documentation
+## � Contract Upgrade Mechanism
+
+### Overview
+
+The ValidFi smart contracts include a robust upgrade mechanism that allows for secure, controlled contract upgrades without data loss. The system uses a proxy pattern with timelock security, state consistency validation, and comprehensive migration tracking.
+
+### Upgrade Process
+
+#### 1. Initialize Upgrade Mechanism
+
+```bash
+# Call initialize_upgrade with admin address and initial implementation hash
+identity_registry.initialize_upgrade(admin_address, initial_wasm_hash)
+```
+
+#### 2. Schedule Upgrade
+
+```bash
+# Schedule an upgrade with a 24-hour timelock
+identity_registry.schedule_upgrade(
+    admin_address,
+    new_wasm_hash,
+    proposed_version
+)
+```
+
+#### 3. Wait for Timelock
+
+The timelock period (24 hours) must expire before the upgrade can be executed. This provides time for community review and emergency cancellation if needed.
+
+#### 4. Execute Upgrade
+
+```bash
+# After timelock expires, execute the upgrade
+identity_registry.execute_upgrade(admin_address)
+```
+
+#### 5. Run Data Migration (if needed)
+
+```bash
+# Execute data migrations for the new version
+identity_registry.migrate_v1_to_v2(admin_address)
+```
+
+### Security Features
+
+- **Timelock Protection**: 24-hour delay prevents rushed upgrades
+- **Admin Authorization**: Only designated admin can schedule/execute upgrades
+- **State Validation**: System checks storage integrity before upgrade
+- **Migration Tracking**: All migrations recorded with version and timestamp
+- **Emergency Pause**: Admin can pause upgrades during critical situations
+- **Dual Authorization**: Admin transfer requires both current and new admin signatures
+
+### Monitoring Upgrades
+
+```bash
+# Check current version
+identity_registry.get_version()
+
+# Check pending upgrade
+identity_registry.get_pending_upgrade()
+
+# Check timelock end time
+identity_registry.get_timelock_end()
+
+# Check migration status
+identity_registry.is_migration_executed(version)
+
+# Get migration record
+identity_registry.get_migration_record(version)
+```
+
+### Emergency Procedures
+
+#### Cancel Pending Upgrade
+
+```bash
+identity_registry.cancel_upgrade(admin_address)
+```
+
+#### Emergency Pause Upgrades
+
+```bash
+identity_registry.emergency_pause_upgrades(admin_address)
+```
+
+#### Unpause Upgrades
+
+```bash
+identity_registry.unpause_upgrades(admin_address)
+```
+
+### Legacy Upgrade Method
+
+For backward compatibility, a legacy upgrade method is available:
+
+```bash
+# Direct upgrade without timelock (not recommended for production)
+identity_registry.upgrade(admin_address, new_wasm_hash)
+```
+
+## � API Documentation
 
 ### Authentication Endpoints
 
@@ -455,6 +566,7 @@ This project is licensed under the MIT License - see the LICENSE file for detail
 - ✅ Basic wallet integration
 - ✅ IPFS integration
 - ✅ AI-powered verification
+- ✅ Robust contract upgrade mechanism
 
 ### Phase 2 (In Progress)
 - 🔄 Health credential-specific zk-proof circuits

contracts/src/errors.rs

@@ -10,4 +10,15 @@ pub enum Error {
     SharedDocumentNotFound = 4,
     Unauthorized = 5,
     AlreadyInitialized = 6,
+    // Upgrade mechanism errors
+    UpgradeNotInitialized = 7,
+    InvalidUpgradeHash = 8,
+    MigrationAlreadyRun = 9,
+    StateInconsistency = 10,
+    UpgradeTimelockNotExpired = 11,
+    ProxyNotInitialized = 12,
+    InvalidImplementation = 13,
+    MigrationFailed = 14,
+    VersionMismatch = 15,
+    StorageCorrupted = 16,
 }

contracts/src/identity_registry.rs

@@ -149,7 +149,35 @@ impl IdentityRegistry {
         upgrade::set_admin(env, &admin);
     }
 
-    /// Upgrade the running contract WASM to `new_wasm_hash`.
+    /// Initialize the upgrade mechanism with admin and proxy pattern.
+    /// This must be called once after deployment.
+    pub fn initialize_upgrade(env: &Env, admin: Address, implementation: BytesN<32>) {
+        admin.require_auth();
+        upgrade::initialize_upgrade(env, &admin, &implementation);
+    }
+
+    /// Schedule an upgrade with a timelock for security.
+    /// The upgrade can only be executed after the timelock period expires.
+    pub fn schedule_upgrade(
+        env: &Env,
+        admin: Address,
+        new_wasm_hash: BytesN<32>,
+        proposed_version: u32,
+    ) {
+        upgrade::schedule_upgrade(env, &admin, new_wasm_hash, proposed_version);
+    }
+
+    /// Execute a scheduled upgrade after timelock expires.
+    pub fn execute_upgrade(env: &Env, admin: Address) {
+        upgrade::execute_upgrade(env, &admin);
+    }
+
+    /// Cancel a pending upgrade.
+    pub fn cancel_upgrade(env: &Env, admin: Address) {
+        upgrade::cancel_upgrade(env, &admin);
+    }
+
+    /// Upgrade the running contract WASM to `new_wasm_hash` (legacy method).
     /// Only the upgrade admin may call this.
     ///
     /// After this call the next ledger-round executes the new code; all
@@ -158,7 +186,7 @@ impl IdentityRegistry {
     /// storage keys.
     pub fn upgrade(env: &Env, admin: Address, new_wasm_hash: BytesN<32>) {
         upgrade::require_admin(env, &admin);
-        upgrade::execute_upgrade(env, new_wasm_hash);
+        upgrade::execute_upgrade_legacy(env, new_wasm_hash);
     }
 
     /// Data migration: v1 → v2.
@@ -198,4 +226,56 @@ impl IdentityRegistry {
     pub fn is_migration_complete(env: &Env) -> bool {
         upgrade::is_migrated_v2(env)
     }
+
+    // ── New Upgrade Mechanism Functions ───────────────────────────────────────
+
+    /// Get the current proxy implementation address.
+    pub fn get_implementation(env: &Env) -> Option<BytesN<32>> {
+        upgrade::get_implementation(env)
+    }
+
+    /// Get pending upgrade information.
+    pub fn get_pending_upgrade(env: &Env) -> Option<upgrade::PendingUpgrade> {
+        upgrade::get_pending_upgrade(env)
+    }
+
+    /// Get the timelock end timestamp.
+    pub fn get_timelock_end(env: &Env) -> Option<u64> {
+        upgrade::get_timelock_end(env)
+    }
+
+    /// Get the current state hash.
+    pub fn get_state_hash(env: &Env) -> BytesN<32> {
+        upgrade::get_state_hash(env)
+    }
+
+    /// Update the state hash for consistency validation.
+    pub fn update_state_hash(env: &Env, state_hash: BytesN<32>) {
+        upgrade::update_state_hash(env, state_hash);
+    }
+
+    /// Get migration record for a specific version.
+    pub fn get_migration_record(env: &Env, version: u32) -> Option<upgrade::MigrationRecord> {
+        upgrade::get_migration_record(env, version)
+    }
+
+    /// Check if a specific migration has been executed.
+    pub fn is_migration_executed(env: &Env, version: u32) -> bool {
+        upgrade::is_migration_executed(env, version)
+    }
+
+    /// Emergency pause: disable upgrades temporarily.
+    pub fn emergency_pause_upgrades(env: &Env, admin: Address) {
+        upgrade::emergency_pause_upgrades(env, &admin);
+    }
+
+    /// Unpause upgrades after emergency.
+    pub fn unpause_upgrades(env: &Env, admin: Address) {
+        upgrade::unpause_upgrades(env, &admin);
+    }
+
+    /// Check if upgrades are currently paused.
+    pub fn is_upgrades_paused(env: &Env) -> bool {
+        upgrade::is_upgrades_paused(env)
+    }
 }