The most efficient technique for protecting the using Frobenius algorithms for scalar multiplication on Koblitz curves against the Side Channel Attacks seems to be the multiplier randomization technique proposed by Joye and Tymen. In this paper, an heuristic analysis on the security of the Joye and Tymen's technique is given. A new method improving this technique is proposed. Analysis shows that the proposed method reduce the cost of the Joye and Tymen's technique by about 50%.