An Improved Chosen IV Attack on Stream Ciphers

A new statistical test, named d-monomial test, has been recently used to perform chosen IV attacks on stream ciphers. The best version of d-monomial test was introduced by Englund et al in 2008. Using this test, they analyzed a few number of reduced round stream ciphers from eSTREAM portfolio. In this paper we will modify the d-monomial test, and introduce a more powerful and efficient test. Our attack exploits the unexpected dependencies between different relations, which are obtained from different IV values. This weakness had not been considered in previous attacks. To show the efficiency of our attack, we performed it on full round Trivium

Keywords:

Stream cipher , Chosen IV attack , d-monomial test , Boolean functions , Trivium