In the early days, the concept of network had not been formed, so
there was no need to consider the security problems of data.
Computer performance was poor and the data computer stored
little, with no hard disk, so no safety-related concept appeared at
that time. With the improvement of computer performance and
the decrease of manufacturing cost, computer obtains the
widespread application, which has greatly promoted the
development of the Internet. According to the latest statistics, the
quantity of netizen in China has exceeded 500 million. In daily
network. Due to the limit storage space of computer, little
important information is stored. Using the cable still cannot
transmit data directly because the data storage structure is
different, so unified transport protocol is essential. While protocol
is for data transmission, safety seemed to be ignored.