PGP (Pretty Good Privacy) is currently the best and most popular data (including texts, e-mails, files, directories, partitions, and whole disk) signing, encrypting, and decrypting program, developed by Phil Zimmermann in 1991. Its source code is open, and it has withstood the challenges from thousands of top hackers around the world. It turns out that PGP is still the most secure encryption software in the world for now (until the popularity of quantum computers, I think). Without a password, no one can decrypt the data encrypted with it!

Network clone (also called multi-cast clone) technology is mainly used to install operating system to, restore data to, backup/copy data from, or make system image from the hard disks of multiple client computers within a local area network (LAN) in batch, thus minimize the time you spend on installing the clients' OS or backuping data one by one every time. Of course, it is an old technology, but in many environments that is still practical and works all right.

Ghost (short for General Hardware-Oriented System Transfer) is an excellent backup & restore tool (commonly known as cloning software) for system, data on hard disk/partition developed by the famous Symantec company from America. For the vast majority of advanced users like system administrator/network manager, it is used to backup the system partition (so as to minimize the time and labor spent on each reinstallation of OS furthest) or data on a disk.

The version names of Norton's security products are really mussy and ruleless (they just change them at will, is this for the purpose of confusing crackers?). But this does make too many users feel confused and puzzled (is my Norton product bought just a few days ago out of date?).