9222

8524

كارشناسي ارشد

مخابرات

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1393

ج،77ص.: مصور،جدول

ص.ع.به فارسي و انگليسي

محمد دخيل عليان

7/8/93

حميد ملا، محمدحسين منشئي

مهندسي برق و كامپيوتر

ID8524

78 Security evaluation of A5 GMR 1 Amir Hossein Kharkan ah kharkan@ec iut ac ir Date of Submission 2014 8 25 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Mohammad Dakhilalian mdalian@cc iut ac irAbstract In order to secure conversations in Satellite Telecommunications based on GMR 1 standard the A5 GMR 1 encryption algorithm is used The internal structure of this algorithm was not publickly knownprior to 2012 and afterward it was revealed by reserve engineering This thesis introduces A5 GMR 1encryption algorithm and compares it with A5 2 stream cipher algorithm and tries to provide a securityanalysis for this algorithm A common approach to analyze any encryption algorithm is to evaluate variousattacks on it Due to the structural similarity between A5 GMR 1 and A5 2 and noting that the prevalentattacks against the A5 2 one of the goals of this thesis is to study the feasibility of Wagner attak against theA5 GMR 1 algorithm In this thesis we prove that this attack is not applicable on A5 GMR 1 As the studyof algebraic attack by linearization method and XL algoritm linearization method is optimized by reducingthe space required for the attack It is shown that the XL method has less memory complexity than theoptimized linearization method whereas its computational complexity on the attack phase is much higherthat the optimized linearization method Keywords 1 stream cipher 2 Wagner Attack 3 Algebric Attack 4 linearization 5 Xl algorithm

محمد دخيل عليان

حميد ملا، محمدحسين منشئي