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.
想一个只有您和要联系的人知道的密语。但不要使用相同的网络连接来交换该秘密。您先输入秘密，然后等待对方也输入该密语。若密语不匹配，则你们之间的通信渠道可能正被监听。