> but how can we blindly trust that this is actually implemented in a closed source system? Threema implements validation mode, something similar can be done f

> but how can we blindly trust that this is actually implemented in a closed source system? Threema implements validation mode, something similar can be done for other closed source messagers: https://threema.ch/validation/ https://threema.ch/validation/ But nobody can guarantee that encryption works when validation mode is disabled.