Custom windows 7 authentication package

A simple, custom authentication package that does the following: * when the user locks the computer it displays a custom image on the standard lock screen (see attached screenshot) * connects to a remote host with TCP/IP and waits for a passcode * when the remote host sends the proper passcode, it unlocks the desktop * integrates into windows' security subsystem, does not circumvent or hack it Requirements: * you must provide the source code * must be compilable with a free/standard compiler (MS c++ compiler preferred) * you must provide a build script * you must provide a short installation instruction document (just one page on how to install an test) or user's manual * it must read the custom image files from a directory * each time the user locks the desktop it should pick a random image from the directory * the custom images are 200x200 pixels png * must use an .ini file (or xml) for it settings with the following content: * valid passcodes * path to the directory of images * remote host name / ip to connect to for passcode * integrates into windows' security subsystem, does not circumvent or hack it Additional info: * It is a part of a concept application/system, so a production quality implementation is not required. Just make sure it works as expected without crashing. * The images displayed on the lock screen are password hints for the user. Their content is irrelevant. * The user logs into a remote system where he specifies the passcode * Protocol with the remote host is as follows * Passcode is a maximum 128bytes long number in HEX encoding. For example: 32BA12CD * When the authentication plugin receives a passcode from the remote host it either sends an 'OK' or 'INVALID' response. * Each message is terminated with an EOL token (ascii CR+LF) * Character encoding is ASCII * when a valid passcode is received, the module terminates the TCP/IP connection (after sending the OK message)