When we think of Trojans, we normally think of the huge wooden horse that the Greeks gifted the city of Troy, in which they had secretly hidden a small number of their warriors. When the Trojans took the horse into the city the soldiers emerged and opened the gates to the cities enemies. Computer trojans are based on the same idea; what can appear to be useful program or harmless site can be hiding a small Trojan program that once it has infected your computer opens a secret backdoor that will allow an intruder to remotely gain access to your computer. Trojans are not viruses in that they are not designed to reproduce themselves. Instead they rely on being small and deceptive to propagate themselves across the internet, usually attached to some other file.

Log files track the activity on a computer so administrators can see who has used the computer, what they did, how long they stayed connected, and where they came from. Since a log file can also record the activity of an unauthorized intruder, much like a surveillance camera can record a burglar breaking into a store, hackers look for the log file as soon as they get access into the computer. Script kiddies often delete the log files to prevent the administrator from seeing exactly what they did on the computer. Unfortunately, deleting the log file reveals the presence of an intruder as blatantly as using a stick of dynamite to get rid of a surveillance camera. The moment an administrator notices that someone has deleted the log file, he or she immediately knows that a hacker must be on the system.

Just because Linux is distributed for free, it doesn’t mean the software is not copyrighted. Linux has been registered as copyrighted under the GNU General Public License (GPL), which is known in the programming community as a copyleft instead of copyright because of its nature. The GPL allows you to redistribute the Linux software, along with the complete source code, to anyone who wants it. However, the original owner of the components retains the copyrights to the software.

This article describes how to use the Windows XP Encrypting File System (EFS) feature to store files in an encrypted format on your hard disk. Encryption is the process of converting data into a format that cannot be read by others. You can use EFS to automatically encrypt your data when it is stored on the hard disk. The Encrypting File System (EFS) is a file system driver that provides filesystem-level encryption in Microsoft Windows (2000 and later) operating systems, except Windows XP Home Edition, Windows Vista Basic, and Windows Vista Home Premium. The technology enables files to be transparently encrypted on NTFS file systems to protect confidential data from attackers with physical access to the computer.