A Reliable Encryption Oriented Pseudo-chaotic Number Generator Using a Key Space Expandable Strategy

Pseudo-chaotic number generators (PCNGs), designed based on multiple chaotic maps, have a significant influence on the security of chaos-based cryptosystems. Since the majority of the chaotic maps are based on real numbers, most of the proposed PCNGs use floating-point notations. However, this data type, especially the double precision notation, has disadvantages of high computation cost and inefficient resource utilization. Also, due to the high sensitivity of the chaotic systems and the finite precision nature of software and hardware platforms, the truncation or round-off errors may cause a big difference in the generated pseudo-chaotic numbers, which may undermine the PCNG's security reliability. To overcome these drawbacks, a new secure PCNG scheme based on the reformulated skew tent maps over a 32-bit integer field is proposed in this paper. It not only reduces the resource utilization from the hardware perspective, but also ensures the PCNG's performance over various operation platforms. Furthermore, the proposed PCNG uses a parameter changeable strategy, which expands the key space of the cryptosystem that adopts the PCNG, and thus increases the immunity against the brute-force attack. The security and statistical test results have demonstrated that the proposed PCNG has reliable security properties with good randomness and it is suitable for cryptographic applications.