• AN EFFICIENT METHOD FOR CONVOLUTIONAL CODES BASED FAST CORRELATION ATTACK

Abstract

Havard Molland et.al. Proposed efficient algorithm for fast correlation attack based on convolutional codes. Their attack had run time complexity of operations with weight equations for LFSR of length . In this paper we improve Havard Molland et. al. method for weight . The run time complexity of our algorithm is . We also improve the data complexity for the attack. The results show that our algorithm gives better performance when error probability is close to .

We also apply our method for finding weight parity-check equations for LFSR of size bits on a cluster machine. Simulation results for the fast correlation attack using these equations are discussed. Correlation attacks for LFSR of such a size have not been reported before.