Improved Cryptanalysis of Polar Bear
Mahdi M. Hasanzadeh, Elham Shakour, Shahram Khazaei · 2006
Abstract. In this paper we propose a Guess-and-Determine based initial state recovery attack on Polar Bear, one of the ECRYPT stream cipher project candidates. The computational complexity and success probability of our attack are O(2 31) and 2-26.4 respectively. Our attack can be considered as one with computational complexity of O(2 57.4) which is much better than the attack recently proposed by J. Mattsson with computational complexity of O(2 79).