Research And Design Of The Firewall Based On Android Smart Phone

The Android platform as a new smart phone platform attracted the attention ofmany developers and users. With the popularity of smart phones and mobile Internet,the Android platform will have a bright future. Mobile phones are more privately used,thus mobile security can cause greater threat to users compared with computers. Thebasic calls and short messaging service are important security issues, especiallyduring the use of the smart phones, the phone rang a sound, strange phone calls, notonly disturbed the normal communication, but also disturbed our normal life; textmessages, the most frequently used mobile phone function, we suffer from all kindsof overwhelming SMS spam, illegal text messages like promotion, fraud, advertisingetc.This paper researched on the Android smart phone calls and SMS firewall anddesigned the firewall. Due to the Android System setups version’s upgrade, shieldingoff part of the application programming interface, brought difficulties to the design ofcalls and SMS firewall. After analysis of the principles of the framework of theAndroid system, we discovered the Android interface description language and theJava reflection mechanism, and by listening to the state of phone calls, finallyre-inherited the class of phone to answer, rewrite the state change method to callblocking function. In mobile phones’ text message filtering module, the existingsoftware filtering rules set rigidly, and its accuracy is not high, borrowed form thespam filter and optimized its corresponding process steps, transplanted it to themobile phone short message filtering. At the same time, according to thecharacteristics of the spam messages, needed for SMS pretreatment, to remove uselesswords and to extract features such operations.The main contents are: designed automatic filtering sub-module for calls andSMS firewall to ensure the firewall module can create good user experience; designedshort message filtering module, focus on the text classifier, applied the naive Bayesianclassification algorithm to message filtering. Test of the overall design of the messagefiltering module and phone calls firewall module indicated that the firewallimplemented phone calls and SMS firewall functions, implanted the two modules inthe phone can effectively protect the safety of mobile phones.