FN_PWCLM – A fusion of piecewise linear and coupled logistic maps to secure different-sized digital images

Abstract

Chaos maps and chaotic systems have made significant strides in the field of cryptography over recent decades. This is primarily because both cryptographic algorithms and chaotic maps share a wide range of common characteristics that render them effective and valuable for communication, stability, and security purposes. Consequently, image encryption based on chaos systems is regarded as one of the most effective methods for safeguarding digital images from attackers. In light of this, a new encryption scheme is proposed to protect digital images, utilizing a fusion of piecewise linear and coupled logistic-chaotic maps to enhance sensitivity to encryption. To further bolster the security of the encryption algorithm, the proposed system preprocesses high-quality pseudo-random sequences into integers ranging from 0 to 255. The cipher structure is designed based on permutation-diffusion processes, where permutation is controlled by four pixels, while diffusion is controlled by rows and columns. An extensive analysis of experimental results, including various types of security analyses, has been conducted. The security analyses have demonstrated that the proposed approach exhibits excellent performance, with high scores for NPCR = 99.61%, UACI = 33.48%, entropy of the cipher image (7.9999 ≅ 8), and correlation coefficient (–0.0009 ≅ 0). In addition to the security and performance analyses, the findings indicate that the proposed algorithm is efficient, secure, fast, and resistant to attacks. Moreover, the algorithm is versatile and can be applied to encrypt images of any size.