Definition of computer security

method of protecting information, computer programs, and other computer system assets. Hardware security, which is the security of computer assets and capital equipment, refers to computer location, access control, fire protection, and storage procedures. Such measures as badges, electronic identification keys, alarm systems, and physical barriers at entries are used for this purpose. Software security entails the protection of software assets such as application program, the operating system, and the Data Base Management System (DBMS) and stored information. Special user numbers and passwords are typically used to prevent unauthorized access to software and data. In addition to security for hardware and software, good internal control also requires that measures be taken to prevent loss or accidental destruction of data.

the protection of computers and the information contained in them. Security measures include frequent backups to protect against data loss due to machine failure, encryption, and password protection to prevent unauthorized access to data; firewall to prevent break-ins through network connections; and physical measures to prevent theft or damage from environmental hazards such as fire or flood.

the protection of computers from tampering, physical danger, and unwanted disclosure of data. The advent of personal computers has made it easy for important business records or confidential data to be lost, sabotaged, or misused. Computers need protection from the following kinds of hazards:

1. Machine failure. Make backups of important files frequently. Every disk drive in the world will one day fail, losing all data.
2. Physical hazards. Protect the computer from fire, flood, and similar hazards, and store backups at a remote location. Remember, too, that the machine can be stolen. An increasing number of computer thieves are after data, not just equipment.

   When traveling with a laptop computer, never let it out of your possession. Many thefts occur at airport check-in counters: while you are preoccupied making your arrangements, someone can quietly steal the laptop computer you placed on the floor. Keep the computer in your hand. Stay close to the computer as it goes through the airport security check. Always bring your laptop on board as carry-on luggage. Checked baggage is treated far too roughly.

3. Operator error. It is easy to delete information accidentally. This hazard can be minimized with software that retains original files while altered copies are being made.
4. Computer tampering. Can someone come in and alter your records without your knowing it? Bear in mind that large numbers of people know how to use popular business software packages. If possible, use software that keeps records of changes-recording who made them and when-and requires validation (such as a password) to make unusual changes.
5. Malicious programming. Some computer crimes have been perpetrated by programmers who did such things as collect all the money that was lost by rounding interest payments to the nearest penny.A clever bookkeeping system run by a dishonest programmer can easily conceal abuse.

   More recently, some people have gotten their kicks by distributing destructive computer programs over the Internet. See Trojan horse. Even more have gotten their kicks by circulating false warnings (see hoax).

6. Malicious programs arriving in e-mail, often falsely described as other things. Never open a file that arrives unexpectedly, even if it's from someone you know, unless you have confirmed what the file is. See worm, worm virus.
7. Break-ins by modem or network. Make sure you know all the possibilities for connecting to your computer from elsewhere, and that you've blocked all access that you don't want to allow. The UNIX operating system, designed originally for use in laboratories where no security was needed, is generally thought to be particularly vulnerable.See dictionary attack; war dialing.
8. Be especially careful with wireless networks, and make sure all communications are encrypted. A cracker with a special antenna can access your wireless network from ten times the normal distance. See war driving; wireless network.
9. Easily guessed passwords. A computer password must never be a person's initials, nickname, child's name, birthdate, etc., nor should it be a correctly spelled word in any language.A common way to crack accounts is to try all the words in a large dictionary, as well as all names and abbreviations that are associated with a person. Also, if a user signs onto a computer and then leaves the terminal unattended, others can tamper with it without typing the password.
10. Viruses and known software defects. Always run antivirus software, and make sure your software and operating system are kept up to date.
11. Excessive security measures. Excessive attempts to build security into a computer can easily make the computer so hard to use that productivity is crippled. In the final analysis, all computer security depends on human trustworthiness. Concentrate on securing the people, not the machine. That is, ensure that employees are trustworthy and that strangers have no access to the machine; then give authorized users all the access they need to do their jobs effectively.