WHOREAD THE FOLLOWING PASSAGE AND MARK THE LETTER A, B, C, OR D ON YOUR ANSWER SHEET TOINDICATE THE CORRECT ANSWER TO EACH OF THE QUESTIONS FROM 31 TO 35

Câu 30 (NB):

A.

when

B.

which

C.

why

D.

who

Read the following passage and mark the letter A, B, C, or D on your answer sheet to

indicate the correct answer to each of the questions from 31 to 35.

One of the greatest security threats in the online world is computer hacking. Hackers are people

who illegally enter systems.

They

may alter or delete information, steal private information, or

spread viruses that can damage or destroy files. But how exactly can a hacker get into a system

to do these things?

Most hackers use information called protocols that are built into computer software. These

protocols allow computers to interact with one another. Protocols are sort of like computer

police officers. When a computer connects to another system, the protocols check to see if the

access is

valid. The protocols can also determine how much information can be shared between

the two systems. Hackers can manipulate the protocols to get unlimited access to a computer

system.

In fact, just the act of entering a computer network is commonly considered passive hacking.

Passive hackers get a rush from just being able to access a challenging system like a bank or

military network. Another kind of hacker tries to do damage to a system. After hacking into

systems, these hackers release viruses or alter, delete, or take information. Known as active

hackers, they are the more dangerous of the two.

The easiest way to protect a system is with a good password. Long and unusual passwords are

harder for hackers to guess. For even greater security, some online services now use “password-

plus” systems. In this case, users first put in a password and then put in a second code that

changes after the user accesses the site. Users either have special cards or devices that show

them new code to use the next time. Even if a hacker steals the password, they won’t have the

code. Or if the hacker somehow gets the code, they still don’t know the password.