Think of a question to which the answer is known only to you and your contact. Enter the question and answer, then wait for your contact to enter the answer. If the answers do not match, the communication channel you are using may be under surveillance.
Pensa a un question al que le responsa es note solo pro te e tu contacto. Insere le question e responsa, e pois attende que tu contacto insere le responsa. Si le responsas non concorda, le canal de communication que tu usa pote esser sub surveliantia.