An improved Bülban map and its application in multiple image encryption

Abstract

This article proposes a hybrid satellite image encryption algorithm integrating a modified 1D Bülban chaotic map, a Chinese Go-inspired permutation, and Deoxyribonucleic Acid-based encoding. The Bülban variant adds a sinusoidal perturbation to widen chaotic regions and heighten plaintext and key sensitivity for lightweight, high-entropy key-streams suited to on-board constraints, the Chinese Go permutation utilizes movement and capture logs to remap pixel coordinates in a manner dependent on both the key and plaintext. This effectively breaks the long-range spatial structures typical of satellite imagery, and Deoxyribonucleic Acid encoding supplies per-byte rule variability to strengthen diffusion with low computational cost. Security analysis demonstrates exceptional performance: near-ideal entropy ( $$\approx 7.99$$ ≈ 7.99 ), near-zero pixel correlation, and strong differential resistance with number of pixel change rate and unified average changing intensity values of $$99.5927\%$$ 99.5927 % and $$29.27038\%$$ 29.27038 % , respectively. The algorithm also achieves a massive key space of $$2^{478}$$ 2 478 , exhibits robustness to occlusion and noise attacks, and allows for lossless decryption (Structural Similarity Index Measure = 1). With an encryption time of 1.469 seconds for each of the images in a $$256\times 256 \times 256$$ 256 × 256 × 256 pixels image cube, the proposed algorithm balances high security with practical efficiency for satellite imaging pipelines.