diff --git a/lib/src/model/json/signal_identity.dart b/lib/src/model/json/signal_identity.dart
index f2f7400..7b10c76 100644
--- a/lib/src/model/json/signal_identity.dart
+++ b/lib/src/model/json/signal_identity.dart
@@ -5,8 +5,10 @@ part 'signal_identity.g.dart';
 
 @JsonSerializable()
 class SignalIdentity {
-  const SignalIdentity(
-      {required this.identityKeyPairU8List, required this.registrationId});
+  const SignalIdentity({
+    required this.identityKeyPairU8List,
+    required this.registrationId,
+  });
 
   final int registrationId;
 
diff --git a/lib/src/services/api.service.dart b/lib/src/services/api.service.dart
index 648c853..fb5246f 100644
--- a/lib/src/services/api.service.dart
+++ b/lib/src/services/api.service.dart
@@ -356,10 +356,11 @@ class ApiService {
 
     final challenge = result.value.authchallenge;
 
-    final privKey = (await getSignalIdentityKeyPair())?.getPrivateKey();
+    var privKey = (await getSignalIdentityKeyPair())?.getPrivateKey();
     if (privKey == null) return;
     final random = getRandomUint8List(32);
     final signature = sign(privKey.serialize(), challenge, random);
+    privKey = null;
 
     final getAuthToken = Handshake_GetAuthToken()
       ..response = signature
diff --git a/lib/src/services/signal/identity.signal.dart b/lib/src/services/signal/identity.signal.dart
index 440fc88..1ad5080 100644
--- a/lib/src/services/signal/identity.signal.dart
+++ b/lib/src/services/signal/identity.signal.dart
@@ -72,12 +72,14 @@ Future<List<PreKeyRecord>> signalGetPreKeys() async {
 Future<SignalIdentity?> getSignalIdentity() async {
   try {
     final storage = FlutterSecureStorage();
-    final signalIdentityJson =
+    var signalIdentityJson =
         await storage.read(key: SecureStorageKeys.signalIdentity);
     if (signalIdentityJson == null) {
       return null;
     }
-    return SignalIdentity.fromJson(jsonDecode(signalIdentityJson));
+    final decoded = jsonDecode(signalIdentityJson);
+    signalIdentityJson = null;
+    return SignalIdentity.fromJson(decoded);
   } catch (e) {
     Log.error("could not load signal identity: $e");
     return null;
@@ -118,7 +120,7 @@ Future createIfNotExistsSignalIdentity() async {
 }
 
 Future<SignedPreKeyRecord?> _getNewSignalSignedPreKey() async {
-  final identityKeyPair = await getSignalIdentityKeyPair();
+  var identityKeyPair = await getSignalIdentityKeyPair();
   if (identityKeyPair == null) return null;
   final signalStore = await getSignalStore();
   if (signalStore == null) return null;
@@ -130,6 +132,8 @@ Future<SignedPreKeyRecord?> _getNewSignalSignedPreKey() async {
     signedPreKeyId,
   );
 
+  identityKeyPair = null;
+
   await signalStore.storeSignedPreKey(signedPreKeyId, signedPreKey);
 
   return signedPreKey;