Enable database encryption for new logins on Nightly/PR builds. (#2328)

- Slightly reworks where the pusher client ID is generated.

ElementX/Sources/Services/Keychain/EncryptionKeyProvider.swift

@@ -0,0 +1,26 @@
+//
+// Copyright 2023 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import CryptoKit
+import Foundation
+
+struct EncryptionKeyProvider: EncryptionKeyProviderProtocol {
+    func generateKey() -> Data {
+        SymmetricKey(size: .bits256).withUnsafeBytes { bytes in
+            Data(Array(bytes))
+        }
+    }
+}

ElementX/Sources/Services/Keychain/EncryptionKeyProviderProtocol.swift

@@ -0,0 +1,21 @@
+//
+// Copyright 2023 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+
+protocol EncryptionKeyProviderProtocol {
+    func generateKey() -> Data
+}

ElementX/Sources/Services/Keychain/KeychainController.swift

@@ -113,7 +113,14 @@ class KeychainController: KeychainControllerProtocol {
     
     func saveSessionInKeychain(session: Session) {
         MXLog.info("Saving session changes in the keychain.")
-        let restorationToken = RestorationToken(session: session)
+        
+        guard let oldToken = restorationTokenForUsername(session.userId) else {
+            MXLog.error("Failed retrieving the restoration token for \(session.userId)")
+            fatalError("Something has gone mega wrong, all bets are off.")
+        }
+        let restorationToken = RestorationToken(session: session,
+                                                passphrase: oldToken.passphrase,
+                                                pusherNotificationClientIdentifier: oldToken.pusherNotificationClientIdentifier)
         setRestorationToken(restorationToken, forUsername: session.userId)
     }