SILC (Secure Internet Live Conferencing) is a protocol which provides secure conferencing services on the Internet over insecure channel. SILC superficially resembles IRC, although they are very different internally. They both provide conferencing services and have almost the same set of commands. Other than that, they are nothing alike. The SILC is secure and the network model is entirely different compared to IRC.
SILC is much more than just about encrypting the traffic. SILC provides security services, such as sending private messages entirely secure; no one can see the message except you and the real receiver of the message. SILC also provides same functionality for channels; no one except those clients joined to the channel may see the messages destined to the channel.