5389

5049

كارشناسي ارشد

مخابرات ﴿شبكه﴾

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1389

نه،93ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

مهدي برنجكوب

حسين سعيدي

23/5/89

مهندسي برق و كامپيوتر

ID5049

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

93 The Analysis of Secure Time Synchronization Methods in Wireless Sensor Networks Zahra Ahmadi z ahmadi@ec iut ac ir Date of Submission 2010 6 8 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Mehdi Berenjkoub brnjkb@cc iut ac irAbstractIn recent years development of wireless communications and ability to design andmanufacture of sensors with low energy usage small size and low cost cause thesenetworks to be used widely Energy process and memory constraints as major restrictionsin these networks need researchers efforts to achieve new and creative solutions Accessto the secure networks particularly is vital consistent to having low energy consumption One of the important problems of these networks is synchronization of the nodes Preciseand synchronized clocks can be more important in sensor networks than the others Adversary tries to disturb time synchronization by altering and faking messages delayingor replying them compromising the nodes and sending false messages via them Inaddition to the importance of secure synchronization in some secure applications andcryptographic protocols synchronization is needed So there is a trade off betweensecurity and synchronization In this thesis we have focused on secure synchronization Up to now there is not any method that be able to provide both synchronization andsecurity needs of sensor networks simultaneously In the other word there has not beenany efficient technique that be resist against all attacks including inciders via compromisednodes yet In the thesis in this way we study at first requirements of secure timesynchronization in context of sensor networks then the available solutions along with theirweaknesses The suggested method is capable to provide precise synchronization lowcommunication and computational overhead low convergence time and high securityagainst internal and external attacks This method uses broadcast authentication to preventaltering and faking the messages as well as comparing measured delay with a giventhreshold to object intentional delay In comparison with TESLA method that is anefficient broadcast authentication method the suggested authentication method has someadvantages The most important one is that it do not need initial synchronization Alsoredundancy helps this method to be resilient against compromised nodes Simulationsshow that our synchronization method has good precision and convergence time Moreover the communication and computational overheads in our scheme are absolutelymild Keywords wireless sensor network synchronization secure synchronization authentication pulse delay compromised node

مهدي برنجكوب

حسين سعيدي