The Essentials of Replacing MSGINA.DLL white paper contains:
SummaryThe information in this white paper expands upon and clarifies the current documentation for replacing the Microsoft Graphical Identification and Authentication DLL (MSGINA.DLL), and is presented in the context of how the MSGINA.DLL works. This content is related to the documentation released by MSDN (Microsoft Developer Network) in October 2000.
Be aware that attempting to use a new GINA can cause a system to fail to boot correctly. If this problem affects you, refer to the section "Recovering From a GINA-related System Failure" at the beginning of the document.
Other MSGINA topics covered include: the responsibilities for Winlogon, standard features, necessary functions and helper functions.