soChat - secure instant messaging service.

This is a server-based messaging service. The assumptions are that the server contains the list of usernames, and the respective salted Lamport's n-fold hashes.

The login protocol for each client securely establishes a symmetric key for client-server communication.

Actual messaging between clients is established though a modified Needham-Schroeder protocol; the server is used as an intermediary to mutually verify the clients' identities and establish an ephemeral shared key.

First, go into the _bin/ directory, which contains runnable JAR files.

These instructions are for Windows. Both the client and the server have configuration files.

To run the server: java -jar server.jar 9000

To run the client: java -jar client.jar

Registered users:

Username          Password 
saba              sabap
oleg              olegp
joni              jonip
amirali           amirp
guevara           guevp

To get a list of connected users, type:

list 

in the command prompt. This command is called automatically when a user connects at first. To send a message to another user, for example, to send a message to oleg as saba, type:

send oleg WHATEVERMESSAGEYOUWANTTOSEND

into the command prompt. The thing to note here is that it is only possible to send a message to the user you know is connected, thus, if you have called the list command and the recipient user has showed up on that list. If the user you want to send a message to connected after your last list command, you won't be able to send him a message unless he contacts you first or until you call the list command again.