Abstract: A TCML-based spatiotemporal chaotic one-way Hash function with changeable parameter was constructed based on the analysis of sensitivity to initial value and parameters of one-way and two-way coupled map Lattice(TCML) systems.The approach is implemented by employing part of the initial values of coupled map system as the secret key, and the parameters of two-way coupled map system in each iteration is dynamically determined by the value of the last iteration and the corresponding message bit in different positions，and then making message with multigrid embedded in spatiotemporal chaos track in parallel. Choosing some suitable spatial items of the result of the final iteration, the Hash value was obtained by means of linear transform limited with 128 bits.Iteration process has very strong irreversibility and sensitivity to initial values and parameters. Each bit of Hash value has very sensitive, complex and strongly nonlinear coupling relation with the corresponding message and secret key because of the bidirectional diffusion and confusion characteristics. Simulation and analysis demonstrate that the algorithm satisfies all the performance requirements of Hash function and is reliable，secure and efficient.

Keywords: 
• Hash function /
• spatiotemporal chaos /
• coupled map lattice