Transport Layer Security or TLS is the successor to the earlier Secure Sockets Layer (SSL). When correctly deployed this form of encryption makes it harder for third parties to eavesdrop, spoof or alter electronic communications.
It is necessary for sensitive information transfer, but it can be used for anything. See for example the HTTPS Everywhere campaign.
VLC media player has supported TLS for the HTTP Interface and HTTP stream output since 0.8.1, TLS for VoD since 0.8.2, and TLS for ftp and sout access since 2.2.0. In 3.0.0 an HTTP/TLS access module was introduced for HTTP 2.0 support.