this page you will find some information about Filetopia which will
primarily be of interest to our more technically minded users.
In common with most Internet applications,
Filetopia is based on the Client / Server paradigm for chatting
and file sharing. In both cases the Client side is based on Asynchronous
(event driven) sockets while the Server side is Multi-threading.
There is only one Chat Server that is accessed by all Filetopia
Users. And every Filetopia user has one File Server while connected,
the number of File Clients is variable and depends on the number
of simultaneous file transfers originating in the user's machine.
Filetopia uses the Public Key paradigm for communications
with the Chat Server and all File transfered among users.
A public/private key pair is generated on each side of the connection
and the public keys are exchanged. Thus, every connection
consists of three encryption components: A Public Key mechanism,
for which the Elliptic Curve algorithm is used, and a Symetric Encryptor
and Decryptor for which you have a choice of ten
ciphers, many of which are AES
The key size of the symmetric encryption
components is of 256 bits by default.
protocols implemented in Filetopia are on top of the TCP stack,
although Chat among users is carried out using an UDP port. Consequently
all users connected to Filetopia have 3 ports "listening". A random
(or user chosen) TCP port is the File server, port https for DCC
Chats and a random (or user chosen) UDP port is waiting for chat
messages. For security reasons, random ports make the Filetopia
users less vulnerable to attacks.
The Collection Manager Binary List format (.CML) is compressed
to take less disk space and reduce bandwidth while speeding up the
file exchange protocol. The compression algorithm used in this version
is based on a variation of the very well known LZW (Lempel Zif Welch)
algorithm. Compression and de-compression is extremely fast when
this technology is used, whilst the compression ratio remains acceptable.
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