An algorithm to construct a stream cipher system is presented by defining a contaminated dynamic system,in which the two-dimensional Henon dynamic system is contaminated by the twodimensional Logistic dynamic system.By generating two columns of keys,this algorithm can effectively solve the problem that the output is not very sensitive to the change of the low bit of the input.The results of safety tests,such as computer simulation,runs test,correlation analysis,sensitivity analysis and balance test,etc.show...