MD5 Hash Check is a basic Joomla Security tool for a little security checks over all your Joomla files. The Tool Scans and compares the the MD5 code of all your core Joomla files and listings any modified or missing files.
The extension is very useful while updating websites to newer Joomla versions or cleaning up infected websites.
What does it do?
MD5 Hash Check verefies the hashes of your Joomla installation files with that of the original Joomla files. Red more about MD5 values here.