This is a Windows system installed file with Windows File Protection (WFP) enabled.
There are 31 versions of rshx32.dll in the wild, the latest version being 6.1.7600.16385 (win7_rtm.090713-1255). The average file size is about 41.11 KB. Some variations of the file have been seen to be installed with the program NVIDIA Drivers from NVIDIA Corporation.
(Note, the programs listed below are for all versions of Security Shell Extension.)
(Note, the behaviors below are for all versions of rshx32.dll, select a unique version for details.)
Located in the registry at 'SOFTWARE\Microsoft\Windows\CurrentVersion\Shell Extensions\Approved'
United States installs about 45.58% of Security Shell Extension.