-messages, private messages, nicknames and various commands. Difference
-to other chat protocol is in the design of the protocol. The SILC
-protocol has been designed from the day one security in mind and it
-shows in the protocol design.
-<br /> <br />
-
-Generally it is assumed that the SILC Network is trusted. This means
-that clients can fully trust the servers and routers in the SILC Network.
-In real life this is not always possible. In the Internet it is possible
-that some server or router would get compromised by a malicious
-cracker. However, if the SILC Network is closed network, for example
-inside a orgranization the assumption generally is true. The SILC
-protocol is secure even if the end users consider the network
-untrusted, and provides several ways to still have secure conversation
-on the SILC Network.
-<br /> <br />
-
-The packets in the SILC network are always encrypted. It is not possible
-to send unencrypted messages in SILC. This assures that end user cannot
-even accidently send unencrypted messages while thinking that it is
-encrypted. This is the problem of most other chat protocols that provide
-so called plugin encryption. They are not secure by default but try
-to provide security by applying external security protocol such as PGP
-or SSL. In these cases the security is achieved usually by encrypting the
-data while key management and other security issues may be left out, leaving
-the implementation vulnerable to various security problems. The other
-problem is also that the external protocols tend to leave the network
-only partly secured; usually only two points in the network are secured
-with for example SSL. While SSL does provide provable security it is not
-enough to provide security for a chat network as a whole.
-<br /> <br />
-
-The network topology is also different to various other chat protocol,
-like for example IRC. IRC has tree style network where SILC has so
-called cellular network. A cell consists of a router, servers and clients.
-The cell can also have backup routers in case the private router becomes
-unresponsive.
-
-<br /> <br />
-<img src="img/silc_network.png" alt="( SILC Network - IMAGE )" />
-<br /> <br />
+messages, private messages, nicknames, various commands, and secure
+file transfer. Difference to other chat protocol is in the design of
+the protocol. The SILC protocol has been designed from the day one
+security in mind and it shows in the protocol design.
+<p>
+
+The packets and messages in the SILC network are always encrypted and
+authenticated. It is not possible to send unencrypted messages in SILC
+at all. This assures that end user cannot even accidently send unencrypted
+messages while thinking that it is encrypted. This is one of the problems
+of most of the other chat protocols that provide so called plugin encryption.
+They are not secure by default but try to provide security by applying
+external security protocol such as PGP or SSL over the insecure chat
+protocol. In these cases the security is achieved usually by encrypting the
+data while key management, message authentication and other security issues
+may be left out, leaving the implementation vulnerable to various security
+problems. The other problem is also that the external protocols tend to
+leave the network only partly secured; usually only two points in the
+network are secured with for example SSL. While SSL does provide provable
+security it is not enough to provide security for a chat network as a whole.
+<p>
+
+SILC is secure in environment of mutual distrust between entities
+in the network. It is possible to encrypt messages end to end, so that only
+the sender and the receiver is able to encrypt and decrypt messages. It
+is also possible to send messages to group of users, so that only the
+specified group of users is able to encrypt and decrypt messages. Many
+times the protocol use keys that are generated by the servers, so that
+if other external key exchange methods fail the network still remains
+encrypted. However, it is always possible to negotiate and use locally
+generated keys to secure messages, so that the servers do not know the
+key.
+<p>
+
+Like so many other contemporary chat protocols, SILC too provides
+file transfer. It is possible to transfer files securely between users
+in the SILC Network. The actual file transfer stream is always sent
+outside the network peer to peer. Before the file transfer is started
+a key exchange protocol is executed to negotiate file transfer session
+key.
+<p>
+
+The network topology is also different to various other chat protocols,
+like for example IRC. IRC has tree style network, but SILC network can be
+described more as an hybrid ring-mesh network. The routers in the network
+form a ring, but they can also have other direct routers (secondary routes)
+to other routers. A router in the network is also called a cell, when it
+has multiple servers and clients connected to it. The cell can also have
+backup routers in case the primary router becomes unresponsive.
+
+<p><br>
+<object data="silc_network.jpg" type="application/postscript">
+<img src="silc_network.png" alt="SILC Network" align="center" border"0">
+</object>
+<p><br>