Difference between a digital certificate and digital signature.

Q12. What is the difference between a digital certificate and digital signature?
Ans. A digital certificate is a electronic file is issued by a certification authority, such as Thawte, to websites. A Digital Certificate helps assure users that the website they are visiting is trustworthy. On the other hand, a digital signature helps the user ensure data integrity and authentication. It is a digital code, which is attached to an electronically transmitted data to uniquely identify the sender.



Differentiate between hackers and crackers with the reference to their intention and motive.

Q11. Answer the following questions:

  1. Shreenivasan is working for an IT firm where he needs to take a backup of his data of around 200MB to 400MB at the end of each day. The backup he takes everyday needs to be achieved separately for future reference. Suggest any two economic data backup devices, which he can use for this purpose.
  2. Differentiate between hackers and crackers with the reference to their intention and motive.
  3. Name one specific software/ tool for each of the following categories:

1. Anti-virus software
2. Data recovery tool
3. Online backup tool
4. Text editor to create HTML pages
5.Open Source web browser

  1. CD and DVD
  2. Hacker is a slang term for a person who is passionate about computers, one who enjoys gathering any type of information about computers and programming languages. The term is sometimes used derogatorily to mean a person who uses this knowledge to break into a computer to steal sensitive information. In simple word, hackers are people who break into a computer with no malicious intention. On the other side, crackers are the people who gain unauthorized access to a computer with the intention of stealing information or causing harm to the computer by destroying its software. However, the popular mass media finds no distinction between the two terms and uses them interchangeably.


1. Anti-virus software: Vipre
2. Data recovery tool: NTFS-reader
3. Online backup tool: Dropbox
4. Text editor to create HTML pages: Notepad2
5.Open Source web browser: Mozilla Firefox

Advantages of online backup.

Q10. What are the advantages of online backup?

Ans. The advantages of online backup are as follows:

  1. Cost less than other modes of backup.
  2. Does not need hardware, such as CD’s and DVDs, to take the backup; it saves the user from the trouble of maintaining or repairing the hardware.
  3. Allows the user to restore his/her backup from any location in the world anytime.
  4. Provides a high level of security as the user’s data is encrypted before it is sent to the remote server.
  5. Keeps the backup safe from threats such as theft, fire, earthquake, and other such disasters as the backup is stored on a remote computer.


Q9. What are worms? Explain with Examples?

Ans. A worm is a program that harms the computer and destroys data stored in it. A computer is a Self-replicating program that uses the network to send its copy from one computer to another. Worms are considered more harmful than viruses because they rely less (or not at all) on human behavior to spread themselves. Computer worms spread much more rapidly than computer virus. Some examples of computer worms are as follows:

  1. MS-Blaster
  2. Sasser worm
  3. SQL Slammer worm
  4. Blaster worm
  5. Melissa worm
  6. Sobig worm
  7. Mydoom worm

Life cycle of a computer virus.

Q7. Explain the life cycle of a virus.

Ans. The following are the different stages in the life cycle of a virus:

Life cycle of a virus.
  1. Creation: Represents the stage when a virus is first created. Till a few years back, knowledge of a programming language was required to create a virus. However, today anyone with knowledge of basic programming concepts can create a virus. Read More …

Common symptoms of a virus attack.

Q6. What are the common symptoms of a virus attack?

Ans. The following are the common symptoms of a virus attack:

  1. The computer begins to run slowly.
  2. Unusual messages and graphics appear on the screen for inexplicable reasons.
  3. Music not associated with any of the open programs begins to play.
  4. Some program or data files on the computer either become corrupt or are difficult to locate. Read More …

Information security.

Q7. Write a note on information security.

Ans. Information security plays an important role in the growth of e-commerce. It can be defined as a set of rules and regulations that users follow online to ensure that the information they provide is not misused in any way. In other words, information security implies protection of information from illegal access or modification.