This is a Windows system installed file with Windows File Protection (WFP) enabled.
There are 32 versions of seclogon.dll in the wild, the latest version being 6.3.9600.16384 (winblue_rtm.130821-1623). The average file size is about 20.72 KB.
(Note, the behaviors below are for all versions of seclogon.dll, select a unique version for details.)
United States installs about 49.43% of Secondary Logon Service DLL.