An optical multiple-image authentication based on computational ghost imaging and total-variation minimization.

An optical multiple-image authentication is suggested using computational ghost imaging and total-variation minimization. Differing from encrypting multiple images into a noise-like ciphertext directly, as described in most conventional authentication methods, the related encoded information is embedded into a cover image to avoid the attention of eavesdroppers. First, multiple images are encoded to form real-valued sequences composed of corresponding bucket values obtained by the aid of computational ghost imaging, and four sub-images are obtained by decomposing the cover image using wavelet transform. Second, measured sequences are embedded into one of the sub-images, and embedding positions are randomly selected using corresponding binary masks. To enhance the security level, a chaotic sequence is produced using logistic map and used to scramble measured intensities. Most importantly, original images with high quality can be directly recovered using total-variation minimization. The validity and robustness of the proposed approach are verified with optical experiments.

Information encryption based on the customized data container under the framework of computational ghost imaging.

In this paper, a novel information encryption scheme has been proposed based on the customized data container, where the primary information can be recovered completely from the ciphertext encrypted with computational ghost imaging. From two aspects, the proposed scheme solves the serious issues caused by the inherent linearity and mechanism of computational ghost imaging. First, the primary information to be encrypted is transformed into the bits of information, which is used to control the formation of the customized data container. Then, the exclusive-OR (XOR) operation is performed on it with a randomly generated data container, and the XOR encoding result is scrambled based on the random sequence engendered with the logistic map so that the linearity of the cryptosystem is destroyed. Second, instead of using random phase-only masks, a number of phase masks retrieved from 2D patterns derived from the rows of the designed Hadamard matrix are used to record the measured intensities. The redundancy between these phase masks is low, which can reduce the number of the required phase-only masks greatly. Meanwhile, the conditions of the logistic map are considered as the secret keys, which can enhance the security level greatly due to their high sensitivity to tiny variation. The validity and feasibility of the proposed method have been demonstrated with a set of numerical simulations.