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Note LogonUser Win32 API does not require TCB privilege in Microsoft Windows
Server 2003, however, for downlevel compatibility, this is still the best
approach.
On Windows XP, it is no longer required that a process have the SE_TCB_NAME
privilege in order to call LogonUser. Therefore, the simplest method to
validate a user's credentials on Windows XP, is to call the LogonUser API.
One other problem with LogonUser is that the API is not implemented on
Windows 95, Windows 98, or Windows Millennium Edition.