united standard is called transport protocol. On the early stage
when the network technology developed, limited by lines, other
infrastructures, and finite transmission bandwidth, achieving
transmission was the main purpose of network. The design of
corresponding transport protocol was based on improving the
efficiency of transmission, and data security, stability of
transmission became a secondary consideration. At that time,
because the network was not well developed, viruses and Trojans
didn’t appear, security need not be considered in the content of
transport protocol. With the advent of transmission equipment
like optical fiber, the bandwidth saved from the transmission
protocol has become negligible. However, the safety problems
resulting from the protocol in the process of transmission have
drew more and more attention.