The paper explores the role of Pass word, Anti virus & information encryption in computer security. It's been discussed that passwords is known to be ancient. Sentries would challenge those wishing to enter an area or approaching it to supply a password or watchword. Sentries would only permit a person or group to pass if they knew the password. In modern times, user names & passwords are commonly used by people during a log in system that controls access to protected computer operating systems, mobile phones, cable TV decoders, automated teller machines (ATMs), etc. Information encryption refers to mathematical calculations & algorithmic schemes that transform plaintext in to cyphertext, a form that is non-readable to unauthorized parties. The recipient of an encrypted message uses a key which triggers the algorithm mechanism to decrypt the information, transforming it to the original plaintext version.

Finally the paper discusses another important computer security application, computer virus which is a computer program that can copy itself & infect a computer without the permission or knowledge of the owner. The term “virus” is also commonly but erroneously used to refer to other types of malware, adware, & spyware programs that do not have the reproductive ability. A true virus can only spread from two computer to another (in some form of executable code) when its host is taken to the target computer; for instance because a user sent it over a network or the Web, or carried it on a removable medium such as a floppy disk, CD, DVD, or USB drive.