Design And Implementaion Of A Instant Messaging System Based On Commercial Cryptography

In recent years,the development of computer technology and the application of wireless network has greatly promoted the popularity of mobile instant messaging.Due to convenience of mobile network communication,instant messaging has become an indispensable tool in people's daily communication and mobile officing.Instant messaging has brought convenience to people,but also brings security risks.On one hand,people want their normal chat content from prying eyes and that privacy is guaranteed,on the other hand,instant messaging systems also need to have the ability to monitor the spreading of illegal information.As for chat content is visible to the server and transmitted in the clear,most of the existing mobile instant messaging tools on the market can not meet people's demand for information security.Aiming at the shortage of traditional instant communication tools,this thesis designs and implements a instant communication system based on commercial cryptography.The main work is as follows:1.We have a systematic analysis of the current situation of instant messaging and the instant communication tools on the current market.And we have conducted research on the theory of instant communication,commercial cryptography,key management and hardware encryption theory,as well as the iOS development technology.2.In order to ensure the privacy and security of information in the transmission process,the hardware encryption is introduced into the instant messaging system,and we design a secure and reliable instant communication system.We implemented the system in a variety of scenarios such as register,login,personal information management,chat,friend management and password changement on iOS platform.And test the system to verify the validity and reliability of the system.3.The secure instant messaging system adopts the cipher text transmission,which guarantees the privacy of the communication content,but the cipher text transmission brings a challenge to the network monitoring.The encryption algorithm is an excellent scheme for the operation of the data in the case of cipher text,but there are still many shortcomings in the practical aspect.In view of this problem,based on the system designed and implemented in front,we design a secure instant messaging monitoring program.The analysis proves that,this scheme is able to monitor the spread of illegal information while ensuring the privacy right of legal communication.