Gadacz – simple internet communicator
It's simple server-client application.
The server application is used to manage the registration of new users, login authorization, and forwarding messages from one user to another.
Each user at the time of registration receives a unique number that is stored in the server application.
The client application is used to register and log on to the server as well as to communicate with other users (clients). It allows to add new users (eg friends) with a unique number that is given to each new user at the time of registration. To add a friend you should know his/her number.