Appendix D: Glossary

A-C

Adware

Programs that display advertisements, often retrieved off the Internet. See Freeware, Open source, and Shareware.

AES

(Advanced Encryption Standard) An encryption standard defined by the United States government. See DES.

Anonymous remailer

A program or website that strips away an email address from a message and then forwards it, allowing you to send email without revealing your identity or location.

Antivirus program

A program that detects and removes computer viruses.

AOL

(America Online) The most popular (and hated) online service in the world.

Assembly language

A low-level machine programming language. Each specific family of microprocessors (such as Intel or Motorola microprocessors) has its own assembly language that allows maximum flexibility in controlling the computer. Most viruses are written in assembly language, although a few are written in BASIC, C, or Pascal.

Back door

A hidden entry point into a computer or program. Hackers often create back doors in a computer so they can return later and quickly bypass any security or log-in procedures normally required.

Back Orifice

One of the most popular remote access Trojan horse programs. See RAT and Trojan horse.

Black hat hacker

Term describing a hacker who uses his or her skills for malicious purposes, such as deleting files and crashing computers. See White hat hacker.

Blowfish

Popular encryption algorithm freely available for anyone to use.

Boot sector

The part of the disk that identifies the disk type (floppy or hard), the size of the file allocation table, the number of hidden files, and the number of files in the root directory. Every disk has a boot sector, which makes every disk vulnerable to boot viruses. See Boot virus.

Boot virus

A virus that infects the boot sector of a disk.

Brute-force attack

A method of discovering a password by exhaustively trying all possible combinations of words and numbers until you find the right one.

C/C++

Popular programming languages used to write most operating systems and programs such as Linux, Windows, and Microsoft Word. C was the original language used to develop Unix, while C++ is an object-oriented version of C.

Censorware

Generic term for programs, such as parental control programs, that block or limit access to certain websites and Usenet newsgroups. See Parental control software.

Checksum

The numeric result of some calculation (for example, a one-way hash function) based on the physical contents of a file, that uniquely identifies that particular file. If the file changes in any way, its checksum also changes. Checksums are often stored in a separate file that may be encrypted, hidden, or saved on a separate floppy disk. Antivirus and anti–Trojan horse programs use checksums to identify when a file may have been altered (and thus possibly infected). Similarly, computer forensics experts often use checksums to verify that a file hasn't been changed since the computer was first seized by the police.

Clusters

One or more sectors on a disk, containing all or part of a file. See Slack space.

CMOS

(complementary metal-oxide semiconductor) A battery-powered chip that stores information about a computer's configuration. Many viruses target this chip because it can keep your computer from working properly.

Cold boot

To turn a computer off and then back on again. See Warm boot.

Companion virus

A now obsolete type of MS-DOS virus that stores itself as a separate file, usually as a .com file. Companion viruses name themselves after an infected program file, such as wp.exe, but with the .com file extension.

Compiler

A program that converts source code into an executable program. See Decompiler.

Cracker

1. A malicious hacker. 2. A type of program that can defeat encryption or copy protection.

Cracking

Defeating a program's copy-protection method or bypassing any password or encryption scheme.

Credit card generator

A program that creates credit card numbers using the same mathematical formula used by the credit card companies.

Cross-platform

Capable of running on multiple operating systems.