In order to improve the crack speed of linux password, the crack core design idea based on dataflow is proposed. After analyzing core crack module MD5 of linux, three crack models are designed, and their ALMs consumption and run speed are analyzed. Under the structure of full pipeline, based on the idea of dataflow, the Linux crack core is designed to crack linux password fast. Experimental results show that while cracking linux password on FPGA of EP4CE40F29C8, the speed can reach up to 24.95 million/s. In the framework of fully pipeline, the idea based on dataflow makes all the pipeline data blocks in efficient working condition. Linux password crack speed increases greatly.