A Study on the Applicability of Cube Attacks to Stream Ciphers

In order to evaluate more accurately the security bounds of stream ciphers, we analyze the suitability characteristics of cube attacks against stream ciphers. We use numeric mapping technique to evaluate the algebraic degree of Trivium, Grain-128, and Acorn v3 on low initialization rounds quickly and accurately. Experimental results show that the cube attack is suitable for low algebraic degree stream ciphers whose algebraic degree increases slowly with the number of cipher initialization rounds and which have a simple non-linear update function.