In the last years, the birth of instant messaging applications transformed the communication, allowing everyone to contact immediately any other person. Of course, two of the main tasks of a communication app are security and speed: we must be sure about who is receiving our message and that no one can intercept the message, but at the same time we need to reach our contacts without having to wait for minutes or hours. That’s why WhatsApp, one of the main apps in this field, signed in 2014 a pact with the Open Whisper Systems to use their Signal protocol, which guarantees end-to-end-encryption.