A Lightweight Chaotic Image Encryption Scheme for IoT Using Cascaded Tent-Sine Maps

The rapid growth of the Internet of Things (IoT) has intensified the need for lightweight yet secure image encryption schemes suitable for resource-constrained devices. General-purpose block ciphers such as the Advanced Encryption Standard (AES) are computationally expensive for such platforms, while many existing chaotic encryption schemes based on one-dimensional maps have either been shown to be vulnerable to statistical attacks or have not been evaluated on actual embedded hardware. This paper proposes a lightweight color-image encryption scheme built on three complementary components: a cascaded Tent-Sine chaotic system that approximately doubles the Lyapunov exponent of its constituent maps, a four-parameter plaintext-dependent key (PDK) mechanism based on the SHA-۲۵۶ hash that resists chosen-plaintext attacks, and a bidirectional cipher-feedback (CFB) diffusion engine that fuses substitution and diffusion in a single pass. Experimental results confirm that the proposed scheme achieves a mean NPCR of ۹۹.۶۱۱۶% and a mean UACI of ۳۳.۴۷۲۹%. The mean information entropy of the ciphertext exceeds ۷.۹۹۹۵, the maximum absolute adjacent-pixel correlation is below ۰.۰۲, and the effective key space is ۲^۱۴۲. Lossless decryption is verified, while competitive throughput is achieved on the target platform. The proposed scheme matches or exceeds recent benchmark chaotic encryption schemes while employing a simpler architecture, making it a suitable candidate for constrained IoT nodes.

کلیدواژه ها:

Image encryption ، Internet of Things ، Chaotic cascade ، Plaintext-dependent key