SSL/TLS certificates and HTTPS
Normal communication on internet is not cryphered, the connection between computers can be easily listened to. By using SSL/TLS certificates the communication between computer of user and server, where websites are stored, is cryphered and can't be listened to or be modified on the way.
Visitors of websites have certainty, that data send to server (names, passwords, credit card numbers etc.) are send only to website operator and no third part can access them during the communication.
At the sa...