CSpace – GPL Secure Chat File Transfer Remote Desktop

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Posted by chattown on June 24, 2009 Leave a comment (0) Go to comments

cspace

If you looking for an Instant Messenger client that has ability to make Text Chat, File Transfer and Remote Desktop securely with Free License (under GPL License) you can try to use CSpace. It works for Windows and Linux

Here are some of the salient points regarding the CSpace architecture:

User Identity
- All users create 2048-bit RSA keys for themselves.
- A user is uniquely identified by his RSA public key.
- Every user has a contact list, which is just a list of public keys known to that user.
- A user assigns names to the public keys in his contact list. This is done because it is easier to display & manage names rather than raw public keys.
- CSpace ensures that there are no duplicate names present in the contact list. This is done to allow a contact name to uniquely identify a public key in the contact list.
- To help with the exchange of public keys between users, a key server is used (somewhat like PGP key servers).
Decentralized Network
- A Distributed Hash Table (DHT) based on the Kademlia protocol is used.
- When a user goes online, a mapping from his public key to his ip-address is created in the DHT.
- CSpace also registers with third party routers, so that the user can receive connections even if he is behind a nat/firewall.
Connection Process
- When an application wants to utilize the CSpace platform, it establishes a local connection to the CSpace instance, and issues a connect request, say, something along the lines of connect(alice,TextChat).
- CSpace obtains the destination user’s public key by looking up the name in the contact list.
- The DHT is used to obtain the destination user’s network location (ip address).
- A TCP connection is established to the destination user’s network address. In case the destination user is behind a nat/firewall, then a proxied connection is established using a third party router.
- A secure channel is established using the TLS protocol.
- The service name which was requested (say TextChat) is sent over the secure channel, and the destination CSpace instance responds with a success code.
- The application which issued the connect request is notified about the successful connection. CSpace proxies the data between the local application and the secure channel. Thus the application only sees a plain TCP connection to localhost.