Most IM messages are unencrypted, so anyone with physical access to the network may pry on the conversation unhindered. BitDefender’s Chat Encryption secures and encrypts IM messages sent between two users running one of the products listed above. SSL is a security technology also known as Secure Sockets Layer that creates an encrypted channel of communication between your computer and the server you are trying to communicate with. In order for a website to be able to create this kind of encrypted channel, it needs to have a SSL certificate installed.”]
Source: https://www.bitdefender.com/blog/hotforsecurity/malware-trivia-episode-11/