Robust image encryption in transform domain using duo chaotic maps—a secure communication

Abstract

The increase of cyberattacks in the field of information security leads to high attention in the digitalized environment. There is a demand for well-organised methods to transmit data securely over the Internet. In the proposed algorithm, a greyscale image is secured by an encryption technique by two stages, i.e. confusion and diffusion. Digital images can be expressed in terms of numeric values called pixels. The images are converted by the integer wavelet transform-domain technique, where the images are separated by approximation and detailed sub-bands. The proposed encryption algorithm is implemented for the approximated sub-bands which contain significant information of the digital image. 1D logistic and 2D tent maps generate chaotic random keys. By various statistical and differential analyses, the robustness of the proposed algorithm is examined by achieving a maximum entropy of 7.997, near-zero correlation and larger keyspace of 1080. With the results, it has confirmed that the enhanced chaos-based Integer Wavelet Transform (IWT) encryption has succeeded to resist any cyberattacks.