A variety of masking schemes have been introduced to protect the block cipher. The critical technology lies on how to implement the nonlinear part with minimal resources. One popular way to solve this problem is using tower field representation. However, this idea always need two variables as inputs for conversion, which may result in suspicious first-order leakages during this operation. In this paper, we apply first-order attacks against variables of the conversion part based on simulation experiments to prove our speculation. The simulation results show that our proposed idea is more efficient than the second-order attacks in the noisy scenario.