Thanks to the development of science and technology, computer
applications have become more and more popular. The use of
computer largely improved the efficiency of work, and the
emergence of the Internet has further promoted the development
of the computer application. Nowadays, the use of computers
can’t work without the foundation of network. For example, the
function of many softwares need the support of network. However,
the existence of the network has brought about lots of risk factors
to the data stored in the computer. The presence of computer
viruses and Trojans possess a serious threat to the use of
computers [1]. To a certain extent, the development of computer
software technology has increased the harm of viruses and
Trojans. In this context, many experts and scholars have done
thorough researches on how to improve the security of computer
network. They summarize some specific measures of safety
protection, which provides security guarantee to a great extent for
the application of computer network technology [2].