GFI LANguard S.I.M. scans your system for important system files, computes an MD 5 checksum for every important system and files this in a database. At scheduled intervals, GFI LANguard S.I.M. scans the list of monitored files, computes another MD 5 checksum and tests the current value against the stored value to determine if the file has been modified. If it detects a change, it notifies the system administrator via email, and logs the occurrence in the security event log.