Security Research Of Trivium Stream Cipher Algorithm

Trivium as a hardware-oriented stream cipher was designed by Christophe De Canniere and Bart Preneel, which is one of the final winners of the European stream project eSTREAM. Because of its simple and elegant structure, it has attached a lot of interest. There have been a lot of experts and scholars to analyze and research its security.In this paper we analyze the Trivium's key stream generation algorithm and its key stream generation equations, then through guess and determine attack based on chosen differential attack, we can solve nonlinear multivariate equations and get remaining bits of internal state so as to break Trivium.In this paper some new analyses are proposed as follows based on the summary of available analyses of the security of Trivium.Firstly, make use of fault injections, i.e. alter special 52 bits of internal state to generate the faulty key stream; Secondly, compute the difference between the faulty key stream and the original key stream to get many extra equations with low degree of internal state; Finally, 45 bits of internal state are guessed to get remaining 243 bits by using the method of Gaussian elimination for solving the linear equations so as to break Trivium. The total complexity is about 266.8.