Think of a secret known only to you and your contact. Do not use the same Internet connection to exchange the secret. Enter the secret, then wait for your contact to enter it. If the secrets do not match, the communication channel you are using may be under surveillance.
Pensa a un secreto note solo pro te e tu contacto. Non usa identic connexion a internet pro excambiar le secreto. Insere le secreto e pois attende que tu contacto insere lo. Si le secretos non concorda, le canal de communication que tu usa pote esser sub surveliantia.