Security-enhanced cloud-based image secret sharing and authentication using POB number system

Recently, the image secret sharing technique based on POB (Permutation Ordered Binary) number systems has drawn attention in academia. Thanks to Singh et al.’s pioneer in combining image confidentiality and authentication to form a cloud-based image cryptosystem using the POB number system. However, for image confidentiality and integrity, there are always two main concerns of a new image cryptosystem: the protection from unauthorized disclosure and the sensitivity of tampering. To claim confidentiality and integrity guaranty of secure image cryptosystems is meaningful only when the cryptanalysis is taken into consideration. In this article, Singh et al.’s scheme has undergone the scrutiny and potential security weaknesses found. First, the secret image may leak under chosen-plain-image attacks. Second, the partial secret key deducible under cipher/share-image-only attacks is shown unneglectable. Precisely, it is potentially problematic since the security of image authentication only relies on the secrecy of the parameter r of POB number systems, but the parameter is also learned to know by a heuristic method. The main weak design has been shown by means of introducing theoretical analyses and conducting some counter experiments. As a result, in this study we have focused on proposing a security-enhanced POB-based image secret sharing scheme with five primary advantages: (1) high security to confidentiality, (2) lossless reconstructed secret image, (3) high security to integrity, (4) high detection accuracy, and (5) low time complexity. The experimental results and the further analysis demonstrate that the simple and secure improvement does work.