Silc

SECURE INTERNET LIVE
CONFERENCING PROTOCOL

(SILC)
BY-

MYNK

Presentation Overview
 Introduction
 History
 About SILC
 SILC Network Topology
 Features of SILC
 Distribution of SILC
 Types of SILC Protocol
 Security Features of SILC
 Future of SILC
 Conclusion.

INTRODUCTION
 The Secure Internet Live Conferencing (SILC) protocol is a
new modern generation chat protocol which provides full
featured highly secured conferencing services.

 The security has been the primary goal of the SILC
protocol.

 All packets and messages travelling in the SILC Network
are always encrypted and authenticated.

 The network topology is also different from traditional
conferencing and other chat protocols.

HISTORY
 SILC, designed by Pekka Riikonen between 1996 to 1999,
was released to the public in the summer of 2000.

 The original implementation of SILC included a client, a
very preliminary server, and implementations of both the
RSA and DES encryption algorithms . In 1998 SILC was
rewritten in C++, which seemed like a good idea.

 Pekka had to stop development yet again in the winter of
1999 as work on his thesis took up his available time.

About SILC
 SILC provides security services. SILC is a protocol which provides
secure conferencing services on the Internet over insecure channel.

 SILC provides security services, such as sending private messages
entirely secure and it provides same functionality for channels.

 Communication between client and server is also secured with session
keys and all commands, authentication data (such as passwords etc.)

 The SILC protocol also supports so called detaching. It is possible to
detach from the server without actually quitting the network.

 The SILC protocol also allows distribution and exchange of public keys
and certificates through the SILC network.

 The SILC network forms so called “hybrid ring-mesh”
network at the router level and “Star network” at the
server level.

 This type of network technology allows better
scalability and faster delivery of packets than
traditional spanning tree style network.

 The network also supports backup routers which can
be used to protect the network against net splits.

Features of SILC
 Secure File Transfer.

 Non-Unique Nicknames.

 Backup Routers

 Channels.

 Private Messages.

 MIME Messages.

 Key Exchange and Authentication.

DISTRIBUTION
 The SILC is distributed currently in three different packages.

 The SILC Client package.

 The SILC Server package.

 SILC Toolkit package . Each package has its intended audience.

 SILC Client package is intended for end users who are looking
for a good and full featured SILC client.

 The SILC Client package currently includes Irssi-SILC
client that supports all SILC features.

 SILC Server package is intended for system administrators
who would like to run their own SILC server or SILC router.

 SILC Toolkit package is intended for developers and
programmers who would like to create their own SILC
based applications or help in the development of the SILC
protocol.

ENTITIES OF SILC
1. Clients
2. Severs
3. Routers

CLIENTS
 A client is a piece of software connecting to SILC server.

 Purpose of the clients is to provide the end user an
interface to the SILC services.

 Used to actually engage the conversations on the SILC
Network, and they can be used to execute various SILC
commands.

 The clients are distinguished from other clients by unique
Client ID.

 When client connects to the server the SILC Key Exchange
(SKE) protocol and SILC Connection Authentication
protocol are executed.

 The result of the SKE protocol is the session key that the
client and server use to secure their communication.

 Client sends to the server are secured with the session key.
The session key expires periodically and the rekey.

SERVERS
 When server connects to its router the SILC Key Exchange
(SKE)protocol and the SILC Connection Authentication
protocol are executed.

 Normal servers connect to router server. Normal servers
cannot directly connect to other normal servers.

 Messages that are destined outside the local server are
always sent to the router for further routing.

 The clients usually connect to the normal server, however ,
clients may connect to router servers as well.

 The servers are distinguished by other servers in
the network by unique Server ID.

ROUTERS
 The router servers are servers that actually handles the
message routing in the network.

 Each of the router in the network is called a cell.

 A cell can have only one active router and it may have
several servers and several clients.

 Router server knows local information and global
information.

 It knows all the clients connected to the network, all
created channels, and all routers and servers in the
network.

 When routers connect to its primary router the SKE and
the SILC Connection Authentication protocols are
executed just like when normal server connects to its
router.

 The session key is used to secure the communication
between the routers.

 All the secondary routes also have their own session keys.

TYPES OF SILC PROTOCOL
1. SILC packet protocol.
2. SILC key exchange (SKE).
3. SILC authentication protocol.

SILC PACKET PROTOCOL
 The SILC Packet protocol is a binary packet protocol.

 provides secure binary packets and assures that the contents
of the packets are secured and authenticated.

 Packets are used in the SILC protocol all the time to send for
example channel messages, private messages, commands and
other information.

 All packets in SILC network are always encrypted and their
integrity is assured by computed Message Authentication Codes
(M A C).

SILC Key Exchange Protocol
 SILC Key Exchange Protocol (SKE) is used to exchange
shared secret between connecting entities.

 The result of this protocol is a key material used to secure
the communication channel.

 This protocol is executed when, for example client connects
to server. It is also executed when server connects to router.

 This is the first protocol that is executed when creating
connection to, for example SILC server.

SILC Connection
Authentication Protocol
 Purpose of SILC Connection Authentication protocol is to
authenticate the connecting party with server or router.

 This protocol is executed when client connects to server also
executed when server connects to router.

 Also provides information for the server about which type of
connection it is.

 SILC Connection Authentication protocol is always executed
after the SKE protocol, session keys has been established already.

 All packets sent in the connection authentication protocol are
encrypted and authenticated

SECURITY
 The entire SILC network is secured and sending
plaintext or unprotected messages is not possible.
 The transport for the SILC packets is protected with
secure binary packet protocol, which assures that the
contents of the packets are encrypted and
authenticated.
 The messages sent in the network, are secured with
message specific keys.
 The keys to secure the packets and messages are
generated with SILC Key Exchange (SKE) protocol.
 All security features in SILC are traditional and
common in the world of cryptography.

Future of Protocol
 The current protocol version is 1.2. This does not mean
that the protocol is perfect and does not need further
development.

 There is still features that are missing from the
protocol , and it is clear that the protocol needs to
mature a bit more.

 There has been a talk about adding features like
permanent channels, more wide channel founder
privileges, and other similar features.

CONCLUSION
 The Secure Internet Live Conferencing (SILC) protocol
is a new generation chat protocol that provides all the
common conferencing services with strong support for
security. It has wide range of security properties that
should meet the highest levels of security
requirements, while not forgetting easy of use.
The network topology offers new architectural
solution with better scalability over traditional chat
protocols.

Silc

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