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We present a fast and efficient hash algorithm based on a generalized chaotic mapping with variable parameters in this paper. We first define a generalized chaotic mapping by utilizing piecewise linear chaotic map and trigonometric functions. Then, we convert the arbitrary length of message into the corresponding ASCII values and perform 6-unit iterations with variable parameters and message values based on the generalized chaotic mapping. The final hash value is obtained by cascading extracted bits from iteration state values. We excessively evaluate the proposed algorithm in terms of distribution of hash value, sensitivity of hash value to the message and secret keys, statistical analysis of diffusion and confusion, analysis of birthday attacks and collision resistance, analysis of secret keys, analysis of speed, and comparison with other algorithms, and the results illustrate that the suggested algorithm is fast, efficient, and enough simple and has good confusion and diffusion capabilities, strong collision resistance, and a high level of security. [ABSTRACT FROM AUTHOR]

We analyze the computational collision problem on a hash algorithm based on chaotic tent map, and then present an improvement of the original algorithm in this paper. More specifically, we utilize message extension to enhance the correlation of plaintexts in the message and aggregation operation to improve the correlation of sequences of message blocks, which significantly increase the sensitivity between message and hash values, thereby greatly resisting the collision. Finally, we evaluate the performance of the improved algorithm by computer simulation, and the results show that it can resist the computational collision and can satisfy the requirements of a more secure hash algorithm. [ABSTRACT FROM AUTHOR]