A chaos-based block cipher based on an enhanced logistic map and simultaneous confusion-diffusion operations

Abstract

Over the years, there has been considerable interest in the area of chaos-based encryption due to the fact that cryptographic algorithms and chaotic maps share a wide-range of similar characteristics. The majority of chaos-based ciphers were designed for encrypting digital images and vast amounts of data. This paper proposes a new chaos-based block cipher algorithm (CBCA) based on an improved logistic chaotic map. To strengthen the performance of the classical logistic chaotic map, a new chaotification method based on a multiplicative inverse function is used which leads to improved properties such as ergodicity and entropy, both of which are desirable for cryptographic applications. The secret key is used to perturb the chaotic variables, and these perturbed variables are used to produce data sequences for the block cipher’s diffusion and confusion structures. The permutation (diffusion) structure is controlled by an ergodic chaotic map, while the substitution (confusion) structure is controlled by the chaotic points themselves. This new ergodicity-based diffusion approach provides higher security and efficiency. The proposed algorithm not only possess good statistical properties provided by the enhanced chaotic map, but it is also key sensitive and uniformly distributed. Statistical evaluation of the proposed algorithm was performed using text and images as inputs to depict its capability to secure various types of media. The performance of the proposed cipher is then compared to other recently proposed algorithms in literature. The performance comparison indicates that CBCA is efficient, secure and that it can be used to encrypt both small and large amounts of data.