Abstract：To analyze the security of ZUC algorithm for resisting guess and determine attack, a guess and determine attack was proposed based on unique 16 bite half word for ZUC algorithm in half word operation. The operation of state transition was transformed to the half word operation, and every state in LFSR was divided into up and down half word. The basic point of the guess and determine attack was computed out by Viterbi-like algorithm. The other unknown states were determined according to the known state of basic points and the operation of half word to recover all internal states. The results show that the proposed attack on ZUC has a computational complexity of 2398 and requires 6 key stream words, which is better than the previous guess and determine attack on ZUC.
2015, Vol. 36 
