- Elliott Sales de Andrade (QuLogic)
[
Secure Internet Live Conferencing (SILC)](
http://silcnet.org/) is a open
instant messaging protocol that stresses security and flexibility.
The SILC protocol can be divided in three main parts:
* SILC Key Exchange (SKE) protocol
* The SKE protocol is used to establish session key and other security
parameters for protecting the SILC Packet protocol. The SKE itself is
based on the Diffie-Hellman key exchange algorithm (a form of asymmetric
cryptography) and the exchange is protected with digital signatures.
* SILC Authentication protocol
* The SILC Authentication protocol is performed after successful SKE
protocol execution to authenticate a client and/or a server. The
authentication may be based on passphrase or on digital signatures, and
if successful gives access to the relevant SILC network.
* The SILC Packet protocol is intended to be a secure binary packet
protocol, assuring that the content of each packet (consisting of a
packet header and packet payload) is secured and authenticated. The
packets are secured using algorithms based on symmetric cryptography and
authenticated by using Message Authentication Code algorithm, HMAC.
SILC protocol additionally defines SILC Commands that are used to manage the
SILC provides channels (groups), nicknames, private messages, and other common
features. However, SILC nicknames, in contrast to many other protocols (e.g.
IRC), are not unique; a user is able to use any nickname, even if one is
already in use. The real identification in the protocol is performed by unique
Client ID. The SILC protocol uses this to overcome nickname collision, a
problem present in many other protocols.
All messages sent in a SILC network are binary, allowing them to contain any
type of data, including text, video, audio, and other multimedia data.
SILC channels (groups) are protected by using symmetric channel keys. It is
optionally possible to digitally sign all channel messages. It is also possible
to protect messages with a privately-generated channel key that has been
previously agreed upon by channel members. Private messages between users in a
SILC network are protected with session keys. It is, however, possible to
execute SKE protocol between two users and use the generated key to protect
private messages. Private messages may be optionally digitally signed. When
messages are secured with key material generated with the SKE protocol or
previously agreed upon key material (for example, passphrases) SILC provides
security even when the SILC server may be compromised.
* [
SILC](
http://silcnet.org/support/documentation/specs/)
## Additional Information * [
Wikipedia](
http://en.wikipedia.org/wiki/SILC_(protocol))
* [
SILC Homepage](
http://silcnet.org/)
