Many of these crimes re never reported to authorities, partly because the losses are often difficult to calculate. Nevertheless, there is a consensus among both law enforcement personnel and computer scientists who specialize in security that both the number of computer crime incidents and the sophistication of computer criminals are increasing rapidly. Estimates are that computer crime costs victims at least five billion dollars each year In the LISA, and the true value of such crimes might be substantially higher. In computer security, there Is a new word: "Information warfare.

While information warfare" is Just another name for computer crime, the word "warfare" does fairly indicate the amount of damage inflicted on society. There are three major classes of criminal activity with computers: unauthorized use of a computer, releasing a malicious computer program (called a "virus") and harassment on the Internet. These are in contrast to merely using computer equipment as a tool to commit old crimes. Unauthorized use of computers generally takes the following forms: unauthorized viewing of computer files, changing data, deleting data, and denying service to authorized users.Most unauthorized use is accomplished by a person who uses a modem to access a remote computer from his house. In this way, the computer criminal is acting analogously to a thief.

To successfully use a remote computer, any user must have both a valid user name and valid password. The criminals who change or delete data, who gobble large amounts of computer resources and who also might use other people's data (such as credit card numbers, social security numbers, and other personal information) have a more sinister motive and are capable of doing Immense damage.The general term is "rogue program" or "malicious program", which is divided into he following types: file-destroying, self - replicating programs, and data congesting. All of them can delete and destroy important data. Not requiring a professional programmer, most malicious programs are made by a person or a small group.

Because nowadays people rely very much on the Internet, they are more likely to be affected by a virus. The last type of computer crime is harassment.In general, a harasser intends to cause emotional distress and has no legitimate purpose to his communications. Harassment can be as simple as continuing to send e-mail to someone who has said they want no further contact with the sender.

Harassment may also include threats, sexual remarks, or pejorative labels. A particularly disturbing form of harassment is sending a forged e-mail that appears to be from the victim and contains racist remarks or other embarrassing text which will tarnish the reputation of the victim.In today's society, computer crimes have become very serious, and often cost a lot of money and destroy important data from companies and people. Therefore, there are some easy and simple ways to teach people and companies how to protect their data and computers by selecting a good password, installing anti-virus software, eating firewalls, using an alias or fake identification, and backing up files. First, to access an online computer service or Internet service provider (ISP) one needs both a user name and password.

Sips typically select a user name that is the same as the last name of the subscriber. This means that user names are easy to guess; therefore, one must be especially careful with the password. There are a few ways to teach how to select a good password. First, you can make the make the length of your password at least five characters.

If you can't have a long password, then you would have a short password which mixes capital and small letters. When you set your password, you should avoid any personal words.Changing passwords every few weeks is also standard advice from computer security experts. Second, computer viruses were generally passed from one user to another user via floppy disks or the Internet, which made anti-virus software essential for all computer users. This software is very fast and easy to use. Viruses were easy to spread because it became common to distribute software and updates via downloads from the Internet and hackers developed viruses that were delivered inside macros for Microsoft Word, where rogue macros could be hidden inside a document and sent by e-mail.

Since everyone uses e-mail and nearly everyone downloads executable software from the Internet, everyone should have a good anti- virus program running on his or her machine to further prevent problems with Third, it is common to erect a firewall between parts of a computer system that an external user can access and parts that are supposedly accessible only by a local user. Now that computers are relatively inexpensive, it makes more sense to have totally separate and isolated machines for external access.The cost of having a operate computer that is dedicated solely to receiving incoming modem connections and requests from the Internet is offset by the increase in security with minimum inconvenience to authorized users inside the building. When a secure computer and a computer for external access are in the same building, communications between them should be via floppy disk, not via wire or cable. Fourth, for on-line activities, you can establish a free e-mail account at Yahoo, Hotmail, or some other provider, and use an alias for that account.

If someone harasses or stalks you, then you simply close that account and chose another alias.In other words, you adopt a disposable identity for your life in the Internet world. Never give out your real name, address, city, telephone number, or other identifying information to a stranger in a chat room, computer bulletin board, or other public place. Last, if a computer virus or an invading hacker deletes or corrupts your files, the easiest way to restore your computer may be to reformat the hard drive and then copy files from a recent backup. Backups also offer protection from more common threats such as accidental deletion of a file by an authorized user or failure of a hard disk drive.When criminals commit crimes, they are likely to say that the criminal did everyone a favor by calling attention to a computer security loophole.

However, one should recognize that even if the victim behaved in an imprudent way, a victim never invites a crime. I am more concerned with computer crimes that are new ways to harm people, instead of the old crimes, which are assaulting in nature. I do realize that it is very hard to prevent computer crime. In order to decrease the serious damage of computer crime, I hope my paper can help people know how to prevent computer crime with some simple solutions.