A novel TriCore scheme for multiple RGB images in telemedicine environments

Abstract

The scientific community is paying high attention to propose efficient solution to the open problem related to security and privacy of still visual communications. Telemedicine is one of the real world applications, experiencing such security concerns related to virtual consultation. Among the presence of already defined encryption schemes, this paper is dedicated to define TriCore, an efficient encryption scheme for multiple RGB images, inspired by three core components: ${\sigma }_{\exists }$-permutation, Laplacian matrix and 4D hyper chaotic system. The use of Secure Hash Algorithm-256 (SHA-256) in key generation assures the randomness and make it highly sensitive. Also, this paper presents a novel ${\sigma }_{\exists }$-permutation, to enhance the randomness effect in the corresponding cipher image. The scheme mainly deals with the matrices corresponding to the three channels of the merged image, undergoing ${\sigma }_{\exists }$-permutation and XOR operations with pair of channel matrices and key matrices, a single cipher image is produced corresponding to multiple RGB images. It prevents the revelation of actual number of shared images and make the scheme more strong. Obtaining the ideal values, experimental results witness the efficiency of TriCore scheme. The entropy is measured as 7.9998. The high resistance against the differential attacks is measured through the Number of Pixel Change rate (99.6158$\%$) and Unified Average Changing Intensity (33.4621$\%$). The execution time for 4 images each of size 256 $\times$ 256 is just 0.173470 s. The experimental results show that this paper efficiently facilitates secure communications in telemedicine providing higher security at lowest computational costs.