Design And Implementation Of High-performance Email Security Gateway System

As the emergence of the Internet technology,provides a great convenience to our lives,email as a communication tool for information exchange,use more frequently.Email besides applied to private exchanges,is becoming more and more widely used in some formal occasions,in order to ensure the safety of the E-mail transmission,avoid the leakage of important information,need to establish such a system,after the e-mail gateway for monitoring review.In this paper,starting from improve the performance of e-mail security gateway system,two key technologies of email security gateway system research and implementation.Existing email security gateway system,generally in the email protocol reduction and content filtering performance is low,the application performance problems in high-speed network environment.Based on text matching technology is studied,for a direct Base64 matching algorithm was improved,based on the keyword prefix hash again,reduce the length of the conflict list;At the same time,the keyword is split into three portions are respectively compared,thus do not need all of the matching text decoding when exact matching,reducing decoding length,so as to improve the efficiency of the email body matching.The experimental results show that the improved matching algorithm based on text filtering performance has the obvious improvement.For e-mail content filtering,matching more email contains,matching memory occupy larger.To reduce the number of email filtering system memory footprint,in this paper,the email address filtering technique are studied,and a variable length bloom filter VLCBF applied to email filtering.For VLCBF in configuration updates problem of frequency shift,and the improved VLCBF algorithm is proposed based on buffer,will update the result in buffer first,and then make unified shift operation.The experimental results show that the improved VLCBF algorithm in email address configuration update has significant improvement in performance.Finally,the above two kinds of improved algorithm is applied in this article,email security gateway system was designed and implemented,and overall architecture of the system and each module has carried on the brief description,finally gives the system function and performance test results.