A Chaotic Colour Image Encryption Scheme Combining Walsh–Hadamard Transform and Arnold–Tent Maps

The third party misuse and manipulation of digital images is a treat to security and privacy of human subjects. Image encryption in the internet of things era becomes more important with edge computing and growth in intelligent consumer electronic devices. In this paper, we report a chaos-based cryptographic algorithm using Walsh–Hadamard transform and chaotic maps for encrypting images. The images are processed channel-wise and two different chaotic maps called Arnold and Tent maps are used for enciphering. The experimental results show that the random chaotic ranges and complex behaviours of chaotic maps improved both the keyspace and security of image encryption–decryption system.