A Novel Visual Secret Sharing Scheme Using Affine Cipher and Image Interleaving

Recently an interesting image sharing method for gray level images using Hill Cipher and RG-method has been introduced by Chen [1]. The method does not involve pixel expansion and image recovery is lossless. However, use of Hill Cipher requires a \(2\times 2\) integer matrix whose inverse should also be an integer matrix. Further, to extend the method for multi-secret sharing, one requires higher order integer matrices. This needs heavy computation and the choice of matrices is also very restricted, due to integer entry constraints. In the present paper we introduce an RG-based Visual Secret Sharing Scheme (VSS) scheme using image interleaving and affine cipher. Combined effect of image interleaving and affine transformation helps in improving the security of the secret images. Parameters of the affine cipher serve as keys and the random grid and encrypted image form the shares. No one can reveal the secret unless the keys and both the shares are known. Further, as opposed to the method in [1], the present scheme does not require invertible matrix with integer inverse. The scheme is also extended for multi-secret sharing.