1st Year Computer Chapter 6 Notes

• What is meant by security?
• What is a computer virus?
• How virus spread from one computer to another?
• Write down some causes of computer viruses.
• List some types of viruses.
• What is a boot sector virus?
• What is a Trojan horse?
• What is Redlof? What are anti-viruses?
• What is meant by data security?
• What is meant by encryption?
• What is meant by protection?
• What is meant by a password?
• What is meant by copyright?
• What is the 1998 Data Protection Act?
• What is the Copyright Act?
• Define backup.
• What is the difference between complete backup and incremental backup?
• Write down the names of different media used for data backup.
• State the purpose of the password.
• What is the 1980 Piracy Protection Act?
• What is the 1984 Cable Communication Policy Act?
• What is the 1987 Computer Security Act?
• What is the 1988 Video Privacy Protection Act?
• What is the Matching Privacy Protection Act of 1988?
• What is the Computer Misuse Act of 1990?
• How can a virus damage a computer? 
• Security is a system of safeguards designed to protect a computer system and data from intentional and accidental damage or access by unauthorized persons. How does a computer system detect whether you are the person who should be allowed access to it? Various means have been devised to give access to authorized people. For this, we have four approaches, as discussed below: 
• What you have: You may have a key, badge, token, or plastic card to give you physical access to the locked-up server room or computer building.
• What you know: Standard user-ids and passwords or some special combination of numbers are given to the users to logon the machine.
• What you do: Normally, the users put their signatures on the documents to confirm their legitimacy as an authorized user.
• What you are: Some security measures are biometrics - biological means of identification i.e. fingerprints, voice recognition, eye retina etc.
• Virus and Antivirus issues: To fully understand the concept of a virus (or worm), first recall the concept of a computer program, what can a program do, and how a program is executed? A program is a sequence of instructions given to a computer. These instructions are for some sort of processing. By processing we mean performing arithmetic and logical operations on the data in the computer memory, manipulating data is storing and arranging two data item to see if they are equal or not, and transmitting data is sending data from one computer to some other computer on a network or via internet. A virus is a program that attaches itself with other executable files by modifying them so that the virus program is also loaded and executed with the execution of these programs. A virus usually performs destructive operation by deleting or modifying (unknowingly) data stored on the storage devices attached to the computer. It is very important to note that a virus is a set of instructions so it cannot physically destroy a hardware (a common misconception). We can formally describe a virus as "A destructive program containing code that can generate copies of itself and attaches itself with other program so that it is automatically executed when those programs are executed". It is important to know exactly how a virus reaches from one computer to another. As the virus attaches itself with files present on a system so the only way, a virus can reach from one computer to another, is when some data is exchanges between these computers either through usb, disks, or the network.
• Note: (I) Some systems use a combination of the above mentioned techniques for individual's identification. (ii) Loss of hardware is not a major problem in itself; it can be recovered by insurance, and the hardware can be replaced. The loss of software is also not a big issue, as if it has been backed up properly, can be re- installed in case of loss. The actual problem lies in the loss of data. It is difficult (though not impossible) to recover it in time in case of transactions based computer systems.