Progressive Multi-Secret Sharing of Color Images Using Lorenz Chaotic System

Multi-Secret Image Sharing (MSIS) systems share multiple images to multiple participants in unintelligible forms that can be recovered using all the shares. This paper employs the concept of progressive secret sharing with MSIS to introduce a new system, where the number of used shares in the recovery process defines the quality of the recovered secrets. The proposed system works for any number of secret color images, and is lossless when all the shares are present. The Lorenz chaotic system, which is numerically solved using Euler method, is used as source of randomness to encrypt the secret images. Image encryption utilizes a long system key to perform the substitution and permutation stages. The system passes all security tests, including statistical analysis and key sensitivity, and it is also robust to noise and crop attacks. The analysis results are within the required ranges for a good encryption system, and they are better than those of the compared MSIS systems.