Cellular automata (CA) have been accepted as a good evolutionary computational model for the simulation of complex physical systems. They have been used for various applications, such as parallel processing computations and number theory. In this paper, we studied the applications of cellular automata for the modular multiplications; we proposed two new architectures of multipliers based on cellular automata over finite field GF(2m). Since they have regularity, modularity and concurrency, they are suitable for VLSI implementation. The proposed architectures can be easily implemented into the hardware design of crypto-coprocessors.