Research And Implementation On Inspection And Monitor Technology Of Instant Messaging

With the rapid development of Internet technology, Instant Messaging (IM) has become a new tool, which provides a novel method to communicate. The IM provides a fresh means of communication. It is very easy for people to work and live enormously. The IM is welcomed by the people and becomes the most popular Internet application.However, while brings convenient to the people, the IM has also brought a lot of security risks and it is easy for the dissemination of illegal information. In view of the problems, monitor the IM communication is on great significance.Under this background, this paper researches the theory about the IM, Network data capture optimization techniques, Message format characteristic discovery technology and protocol reverting technology. The writer designed an integrated system to collect and analyze the technique of the IM and Reduction of integration. The main contributions are as follows:1. In order to increase the rate of data processing, filtering algorithm was proposed after researching the Pre-filter technology by making use of Binary Tree data structure in the process of packet capture. This algorithm make use of the black and write list strategy, saves packets which have IM features and refusals packets which have no IM features. Regarding does not have the obvious features packets to use the Pre-filter algorithm based on Binary Tree structure.2. According to the problems about protocol of the IM, the Message format characteristic discovery algorithm was creatively presented which based on MSA (multiple sequence alignment). This algorithm converts the IM data to message sequences which have the location information, and then gets the format characteristic of the message sequences. This algorithm can apply well in the protocol analysis about the IM.3. In order to get the specific content of communication, the study on the research of the protocol reverting technology of the IM, IP datagram reassembly based on double Linked list and TCP packet reorganization algorithm based on sliding window were proposed. This paper has analyzed the communication mechanism and protocol characteristic of the MSN and QQ thoroughly. Finally, according to the IM protocol obtains the instant messaging, transmission files and voice phone4. On the basis of research on the Inspection and Monitoring technologies, Inspection and Monitor system was designed and implemented. The system uses the idea of total combined, sub-degree advance and object-oriented technology. It is deployed in the export of the LAN, and captures the data using the way of bypass interception, then analysis and revert these data.