Most operating systems include a utility that can encrypt and decrypt data. Uses a secure key that converts the data to a format that will not make sense and is not easily un-encrypted
Defragmentation:
When a file is no longer needed, the file will be deleted leaving a space on the disk. The next file to be saved will use this gap and may have to split up into two or more parts
Data compression
Utility which compresses a data file so that the file size is reduced without losing any detail (lossless) and losing data (lossy). Data needs to be uncompressed to use
