Blockchain anchored chaotic image encryption framework for secure and lightweight integrity verification in distributed networks

Efficient mechanisms for secure image transmission in distributed environments like Internet of Things, Software-Defined Networks, and Cloud systems, that provide confidentiality and integrity are required. The blockchain-based image encryption approaches that are currently available focus on storing and encrypting the images securely; however, they often impose too much computational cost and lack sufficient support for lightweight and decentralized integrity verification. This paper constructs a blockchain-based chaotic image encryption system, which combines the logistic–tent chaotic map, block-level Merkle tree hashing, and permissioned blockchain verification scheme, to realize secure, efficient and tamper-proof image transmission. The proposed framework then uses chaotic pixel permutation and diffusion to create highly randomized cipher images and then hashes them in blocks through the SHA256 hash function to generate a Merkle tree, the root hash of which is permanently written onto a permissioned blockchain. The protocol stores only the Merkle root of the image, rather than the entire encrypted image, greatly alleviating the burden on blockchain storage and allowing for efficient tamper detection and localization when dealing with blocks, and allowing decentralized verification of image integrity. Extensive experiments have been carried out on benchmark natural and medical image datasets and the results proved that our encryption is highly random, the correlation between pixels is low and our encryption withstands statistical attacks, differential attacks, brute force attacks, replay attacks, and ciphertext manipulation attacks, and the recovered images are authentic after verification. The proposed framework shows significant advantages in terms of security, memory efficiency, and efficiency of computation and is well suited for the secure multimedia communication in resource constrained distributed networks by comparing the result with the recent image encryption techniques based on blockchain and chaos.