Computing the Algebraic Immunity Efficiently

The purpose of algebraic attacks on stream and block ciphers is to recover the secret key by solving an overdefined system of multivariate algebraic equations. They become very efficient if this system is of low degree. In particular, they have been used to break stream ciphers immune to all previously known attacks. This kind of attack tends to work when certain Boolean functions used in the ciphering process have either low degree annihilators or low degree multiples. It is therefore important to be able to check this criterion for Boolean functions. We provide in this article an algorithm of complexity O ` md

• Type: Conference
• Year: 2006
• Where: FSE
• Authors: Frédéric Didier, Jean-Pierre Tillich
• Keywords: Boolean Functions, Cryptology, FSE 2006, Low Degree, Low Degree Multiple