Client-Server for Authentication

Every client(IP) is authenticated with a unique code generated by the client side software, based on something unique on the computer (hardware, hdd serial, combination, whatever). Several connections from same ip must be allowed, the ip is authenticated as long as at least one session is active. Criptology is required (maybe openssl). Client must work on WIndows operating systems (32/64bit), preferably only C/C++ with Winapi or MFC wich can be mingw32 project, lcc, i guess VC but i would prefer not to be delphi,VB because I want no dependencies other that winapi or MFC. The client must have an installer. There should be a linux/unix simple client avaible also as clean as possible with dependencies (C and C++ standard libs, openssl libs, mysqlclient libs and hopefully nothing more). The server side should be linux/unix who checks the unique id's from a mysql database. When a client (IP) succesfully authenticates then the server side application INSTANTLY(NO DELAYS!) executes a customisable application (command), server based application of the software must support outside intervention (a tehnician )for accepting that particular code' sent by client computers for authentication. When a client (PC/IP) disconnects (normally or by an error) and it is the last socket for that IP then he must execute another command (we will implement those commands), Also the server side must support reading from the database every 5 minutes "messages for clients" like hello, welcome etc in two ways : global and individual (per client/ID) messages, trough baloon popup sistem which dissapear ONLY after you click on it . The client software must run in background windows/unix and must have an systray icon (windows only )and the popup messages must be there! The source code of the whole project is required! For more details regarding this project we can disguss furthemore after the final bid.