A topologically simple keyed hash function using a single robust absolute-value chaotic map

This paper proposes a keyed hash function using absolute-value chaotic map. The proposed absolute-value chaotic map is simple with a single tuning parameter, and offers robust chaos over specific parameter spaces. Meanwhile, the proposed keyed hash function topology is very simple using only a single map. Hash function operations involve an initial stage when the absolute-value chaotic map accepts input message and initial conditions, and a hashing stage where alterable-length hash values are generated iteratively. Nonlinear dynamics are described in terms of bifurcation diagram, Lyapunov exponent, chaotic waveform, and histogram. Hashing performances are evaluated in terms of original message condition changes, statistical analyses, and collision analyses. Results of hashing performances show that the mean changed probabilities are very close to 50%, and the mean changed bit number is also close to a half of hash value lengths. The collision tests reveal the average mean of 1359 and 1703 for the hash values of 128 bits and 160 bits, respectively. The proposed keyed hash function enhances the collision resistance, comparing to MD5 and SHA1, and is comparable to other complicated chaos-based approaches.