Si l' autenticació ha estat correcta, llavors sabreu que realment esteu parlant amb el vostre amic. Qualsevol impostor tindria moltes dificultats per a saber què hi escriviu, de manera que l' enganxaríeu a l' acte.
If the authentication was successful, then you know that you are really talking to your friend. Any imposter should have a hard time guessing what you're typing in, so you'll be able to catch them in the act.