FLKA is an extension characteristic of files used by a program for securing data called Folder Lock. This protection consists in data encryption. During this operation, an archive in the form of a FLKA file is created, which contains all protected data.

This solution is most often used when storing data on portable media. The file size can be a maximum of 4 GB, which is due to the fact that the program supports disks with the FAT32 file system.