When do you think computer security should be applied or needed?

Answer 1

If a computer ever receives data from any source outside the computer or provides data to an outside recipient - computer security is needed. Since that includes the operator at the keyboard, that means just about every computer needs security. A few devices that have internal computers built into them which receive no outside data and supply no data outside of the device MIGHT get away with no security - but even there some security would be prudent to prevent malicious reprogramming of the internal computer.

When computers were being developed, the main goal was just to get them to work, not to make them "secure". As a consequence there are a lot of avenues to attack computers. The question is not so much IF a computer needs security - it is more a question of HOW MUCH security the computer needs. The degree of security a computer ought to have depends on how valuable the information on the computer is, how critical it is to protect the information from being divulged to unauthorized persons, how important it is that the information remain unaltered (You don't want errors in the data in the computers of the bank where you have an account), how important it is to be able to prove someone sent or received data (for example you want there to be proof that you sent your electronic payments and for the recipients to not be able to deny that they received them), and how critical it is to be able to get data into a computer or out of it when you want to (Any student who had their computer crash just as they were about to print out their term paper can sympathize with this one - just knowing the paper is stored on the computer doesn't help you if you can't get it out. If you include computers that run life support systems, you can see that there are even more critical systems that need to be protected such that they continue to function no matter what).