Research On Message Security Of IM Application Based On Android

With the rapid popularity of smart mobile phones,instant messaging has been one of the most popular mobile application now. But because of the uncontrollable system environment and the IM service provider's benefit, the user's message contents are under the threat of being intercepted and intentionally collection. And because of the opened Android system environment and the huge user community and the user's weak safty awareness, the protection of user privacy is important and necessary.This paper does research at the information transmission security of instant messaging application, getting a summary about the security threat for IM application and the solutions for these threat. And then designed and implemented a security system to protect the IM application from one of these threat.This security system use the Xposed framework and the Hook technology to intercept the IM message sending and receiving interface.Doing message encryption and decryption at the message sending client and privide a end-to-end procetion. Besides, because of the Xposed framework and the Hook technology, this system can finish the interception during the start of Android system without doing any change on IM application, and this system can get a good versatility by generating extensions for different IM applications.Further more, this paper does some test for the security system to proof its security performance, and analyze its influence on IM application's running performance. At last, this paper gives some suggestions for this security system based on its deficiency.