Improving key stream generation for sosemannk stream cipher using two fish block cipher

مقدم أطروحة جامعية

Muhammad, Rana Sad

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم علوم الحاسوب

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2008

الملخص الإنجليزي

Cryptographic techniques play an important role in network security and stream ciphers are one of the main cryptographic techniques that play a very important pan in maintaining security and protecting valuable information from potential misuse. This thesis will introduce updated concepts to stream cipher which are: let the size of slates in LFSR equal to 32 bits rather than 1 bit, let the block cipher algorithm generate initial values of states in LFSR, let the linear complexity of LFSR increased by using key-dependent Sboxes which are derived from block cipher algorithm with using FSM, Also this thesis will introduce two proposal algorithms (Snowfish 1) and the (Snowfish 2) to improve the Sosemanuk stream cipher algorithm by benefiting from the efficient properties of the Two fish block cipher and also use its key schedule, key-dependent Sbox to increase the security, randomness and try to avoid the guess and determine attack of Sosemanuk.

These two proposals use Two fish algorithm rather than Serpent algorithm which was used in the Sosemanuk and also they use key-dependent Sbox rather than static Sbox, They are similar in the same key length (128 to 256 bit), IV length (128 bit), LFSR, FSM and output transformation. This thesis is implemented using Visual Basic 6, 0 language on PC computer type P4 with RAM 504 MB and 2.00 GHz with Intel processor to perform these two proposed systems and also to perform the Sosemanuk system to make a comparison between them by using the tests of randomness, the structural tests and the complexity of the algorithm.

These tests give results that shows the two proposed systems have good results in increasing the security and randomness compared

التخصصات الرئيسية

تكنولوجيا المعلومات وعلم الحاسوب

الموضوعات

• الكتابة
• التشفير
• شبكات الحاسوب
• الرمزية
• الإجراءات الأمنية
• البيانات

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-305152