Design And Implementation Of IM Informtiom Reduction System Based On CUDA

Instant messaging software has become a criminal tool of the lawbreakers committing illegal and criminal acts as it facilitates the people’s life. So governments, enterprises and individual scholars have been strengthening research and supervision over the application of instant messaging software from the legal and the technical levels for the purpose of safeguarding public security, combating crimes, obtaining enterprises’ benefits and researching. The communication processes on Tencent QQ having the largest domestic users, have adopted high-strength encryptions which have used different techniques on its versions. For this reason, surveillance on QQ content restoration has been a lack of effective solutions.The paper studied the communication mechanism on instant messaging software QQ by experiment, deeply analyzed and reviewed on its communication processes, encryptions and string features, then gave a decoding understanding. And a cuda-based IM protocol analytic and restoration system was designed and developed, system consisted of three parts including server-side decoding server, ca lculation-side decoding server and restoration-side ciphertext server. The study was the following:1. Analyzed on the QQ chat process and on the data package feature, and gave a decoding and restoring understanding of QQ content. On analysis of the QQ chat processes(including login, friend information, group list) between client and server by package capture, and summary of the feature values and the screening conditions on different packages, the paper found the detail formation mechanisms on the quadrat ic decryption keys of its different versions, and proposed the capture means of packages including Session Key in QQ login which was very important to decoding subsequent content packages. On this basis, the concept on QQ content decoding and restoring including its detail algorithms was developed.2. Designed and implemented A CUDA-BASED IM INFORMTIOM RESTORATION SYSTEM(CBIIRS). Based on requirement discussion in detail, the C BIIRS system consisted of three parts including server-side decoding server, calculation-side decoding server and restoration-side ciphertext server. Logical architecture and working sequence were made further the analysis, and main interfaces and database list structures were determinated.3. Studied specifically key issues on the to-be-verified passwords’ storage, the decoding-tasks’ distribution computation, and the communication mechanism involved in CBIIRS. The formation rule of password storage was proposed to store and transmit efficiently the password sets. A general parallel computation technique on the CUDA architecture was introduced to increase the decoding speed. According to the rational computing of task distribution on the decoding computation-side, the three registers on CUDA equipment were used properly to maximize the computation efficiency. The optimal communication mechanism on system was selected. O n these bases, the CBIIRS computation capability is Significantly increased than the one of other computing equipment on the same CPU platform.