Double-image optical encryption method with high safety intensity and decryption method thereof

Abstract

The present invention relates to a double-image optical encryption method. The method comprises: two images P1(x, y) and P2(x, y) to be encrypted are respectively taken as an amplitude and a phase to combine a complex amplitude plaintext P(x, y) which clings to a random phase template M0(x, y) and is arranged at the input plane of an optical 4f system; a plane wave generated by a beam of the coherent light is employed to vertically irradiate the input plane of the system, three different random phase templates M1(u, v), M2(u, v) and M3(u, v) are respectively arranged at a frequency spectrum surface at three exposures for applying different frequency domain phase modulation, and the three corresponding intensity graphs I1(x, y), I2(x, y) and I3(x, y) are recorded on an output plane to be taken as the system cryptographs. The present invention further provides a decryption method corresponding to the double-image optical encryption method. The method comprises: providing the initial conjecture of the complex amplitude plaintext; and employing the corrected GS iteration phase retrieval algorithm to perform iteration processing with preset times of the initial conjecture to obtain the plaintext so as to extract two secret images. The double-image optical encryption method with high safety intensity and the decryption method thereof can greatly improve the safety of the encryption method.

Description

technical field [0001] The invention relates to the technical field of information security, in particular to a double-image optical encryption method with high security strength and a decryption method thereof. Background technique [0002] In recent years, the application of optical technology in the field of information security has become more and more extensive. Compared with the traditional simple electronic encryption system relying on computers or digital signal processors, the encryption technology using optical principles has multi-dimensional, large-capacity, High degree of freedom, high robustness, natural parallelism and many other advantages. The optical encryption system based on Double Random Phase Encoding (Double Random Phase Encoding, DRPE) proposed and disclosed by Refregier and avidi in 1995 is the most classic optical image encryption system. Since this encryption system was made public, encryption technology based on optical means has flourished. [...

AI Technical Summary

Problems solved by technology

[0004] Based on this, it is necessary to provide a dual-image optical encryption method with enhanced security and its decryption method for the problem that the plaintext is a single real-valued image in the traditional diffraction-based optical encryption method, which has security risks and low efficiency.

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