Getting Instance of 'UntrustedIdentityException' issue while decrypting the message

[saty-a]

Future<String?> getDecryptedText(String source, String msg) async {
try {
SessionCipher session = SessionCipher.fromStore(signalStore,
SignalProtocolAddress(source, SignalHelper.defaultDeviceId));
Map data = jsonDecode(msg);
if (data["type"] == CiphertextMessage.prekeyType) {
PreKeySignalMessage pre =
PreKeySignalMessage(base64Decode(data["msg"]));
Uint8List plaintext = await session.decrypt(pre);
String dectext = utf8.decode(plaintext);
log("type $dectext");
return dectext;
} else {
return null;
}
} catch (e) {
log(e.toString());
return null;
}
} while running this I'm getting this issue: Instance of 'UntrustedIdentityException'.

[anisalibegic]

I'm getting this exception after few days of using the application. It seems like identity changed but I'm sure nobody reinstalled the app or something like that. How to securly update identity keys if they changed? I'm currently getting Instance of 'UntrustedIdentityException'.

Uint8List? decryptedContent;
try {
  decryptedContent = await sessionCipher.decrypt(preKeySignalMessage);
} on UntrustedIdentityException {
  await signalProtocolStore.removeIdentity(targetAddress);
  decryptedContent = await sessionCipher.decrypt(preKeySignalMessage);
}

I temporary solved by using the previous code but I believe there should be a better way... Any help? @crossle @Tougee