Double-image encryption based on interference and logistic map under the framework of double random phase encoding

A novel double-image encryption approach has been proposed based on optical interference and logistic map. Initially, original images are rearranged into two scrambled components with the use of the random sequence engendered based on the logistic map with the given conditions such as initial value and bifurcate parameter. One component is used as the input image of the framework of double random phase encoding and encrypted into the ciphertext. Another is decomposed into two phase masks, which are placed into the input plane and transform plane of double random phase encoding, respectively. To strength the nonlinearity of the cryptosystem, these phase masks considered as the main secret keys are further encoded by the aid of two random sequences. Because these keys are produced in the encryption process and directly related to original images, the proposed scheme has high resistance against the potential attacks such as chosen plaintext attack. Meanwhile, the parameters such as wavelength, axial distance, and conditions of the logistic map are considered as additional keys, which can enhance the security level further. Most importantly, the annoying silhouette problem existed in the interference-based encryption methods can be avoided effectively. A set of numerical simulations are presented to demonstrate the validity and feasibility of the proposed technique.