Title :
Modified Alternating Step Generators
Author :
Wicik, Robert ; Rachwalik, Tomasz
Author_Institution :
Cryptology Div., Mil. Commun. Inst., Zegrze, Poland
Abstract :
Irregular clocking of Feedback Shift Registers is a popular technique to improve parameters of keystream generators in stream ciphers. Another technique is to implement nonlinear functions. We join these techniques and propose Modified Alternating Step Generators built with Linear and Nonlinear Feedback Shift Registers. Adequate nonlinear Boolean functions are used as feedbacks of shift registers and as output functions of the generator in order to increase its resistance to known attacks. We investigate basic parameters of proposed keystream generators, such as period, linear complexity and randomness.
Keywords :
Boolean functions; cryptography; feedback shift registers; irregular clocking; keystream generators; modified alternating step generators; nonlinear Boolean functions; nonlinear feedback shift registers; nonlinear functions; stream ciphers; Ciphers; Clocks; Complexity theory; Filtering; Generators; Shift registers; Stream ciphers. Feedback Shift Registers. Alternating Step Generator. Period and linear complexity. Randomness;
Conference_Titel :
Military Communications and Information Systems Conference (MCC), 2013
Conference_Location :
St.-Malo
Print_ISBN :
978-83-934848-8-1