Abstract: This paper introduced the principles, detailed steps and algorithms of Cube attack. By comparing Cube attack and AIDA attack, we analyzed its principles in detail, and proved that Cube attack is equivalent to higher order diffc rence in aspect of principle. And then,with discussing linear test,we concluded that Cube attack can be successful with high probability. In particular, this paper gave algorithms of the key steps, and employed them to attack the reduced Trivium. Finally, we improved the Cube attack.

Key words: Cube attack, AIDA attack, Algebraic IV, Higher order difference, Trivium