Optical cryptanalysis is essential to the further investigation of more secure optical cryptosystems.Learning-based at-tack of optical encryption eliminates the need for the retrieval of random phase keys of optical e...Optical cryptanalysis is essential to the further investigation of more secure optical cryptosystems.Learning-based at-tack of optical encryption eliminates the need for the retrieval of random phase keys of optical encryption systems but it is limited for practical applications since it requires a large set of plaintext-ciphertext pairs for the cryptosystem to be at-tacked.Here,we propose a two-step deep learning strategy for ciphertext-only attack(COA)on the classical double ran-dom phase encryption(DRPE).Specifically,we construct a virtual DRPE system to gather the training data.Besides,we divide the inverse problem in COA into two more specific inverse problems and employ two deep neural networks(DNNs)to respectively learn the removal of speckle noise in the autocorrelation domain and the de-correlation operation to retrieve the plaintext image.With these two trained DNNs at hand,we show that the plaintext can be predicted in real-time from an unknown ciphertext alone.The proposed learning-based COA method dispenses with not only the retrieval of random phase keys but also the invasive data acquisition of plaintext-ciphertext pairs in the DPRE system.Numerical simulations and optical experiments demonstrate the feasibility and effectiveness of the proposed learning-based COA method.展开更多
In recent years,metasurfaces that enable the flexible wavefront modulation at sub-wavelength scale have been widely used into holographic display,due to its prominent advantages in polarization degrees of freedom,view...In recent years,metasurfaces that enable the flexible wavefront modulation at sub-wavelength scale have been widely used into holographic display,due to its prominent advantages in polarization degrees of freedom,viewing angle,and achromaticity in comparison with traditional holographic devices.In holography,the computational complexity of hologram,imaging sharpness,energy utilization,reproduction rate,and system indirection are all determined by the encoding method.Here,we propose a visible frequency broadband dielectric metahologram based on the random Fourier phase-only encoding method.Using this simple and convenient method,we design and fabricate a transmission-type geometric phase all-dielectric metahologram,which can realize holographic display with high quality in the visible frequency range.This method encodes the amplitude information into the phase function only once,eliminating the cumbersome iterations,which greatly simplifies the calculation process,and may facilitate the preparation of large area nanoprint-holograms.展开更多
Authentication of the digital image has much attention for the digital revolution.Digital image authentication can be verified with image watermarking and image encryption schemes.These schemes are widely used to prot...Authentication of the digital image has much attention for the digital revolution.Digital image authentication can be verified with image watermarking and image encryption schemes.These schemes are widely used to protect images against forgery attacks,and they are useful for protecting copyright and rightful ownership.Depending on the desirable applications,several image encryption and watermarking schemes have been proposed to moderate this attention.This framework presents a new scheme that combines a Walsh Hadamard Transform(WHT)-based image watermarking scheme with an image encryption scheme based on Double Random Phase Encoding(DRPE).First,on the sender side,the secret medical image is encrypted using DRPE.Then the encrypted image is watermarking based on WHT.The combination between watermarking and encryption increases the security and robustness of transmitting an image.The performance evaluation of the proposed scheme is obtained by testing Structural Similarity Index(SSIM),Peak Signal-to-Noise Ratio(PSNR),Normalized cross-correlation(NC),and Feature Similarity Index(FSIM).展开更多
Single-pixel imaging(SPI)through complex media remains challenging.In this paper,we report high-resolution common-path SPI with dual polarization using random-frequency-encoded time sequences in complex environments w...Single-pixel imaging(SPI)through complex media remains challenging.In this paper,we report high-resolution common-path SPI with dual polarization using random-frequency-encoded time sequences in complex environments where the illumination and detection paths are severely distorted.By leveraging a common-path optical configuration with orthogonal polarization states,a series of dynamic scaling factors can be corrected.The designed random-frequency encoding scheme disperses scattering-induced noise into artifacts to be simply removed.It is demonstrated in optical experiments that the proposed method is feasible and effective to reconstruct highresolution object images in complex environments.The proposed method does not require complex optical components and prior knowledge about scattering media,providing a robust solution for high-resolution optical imaging in complex scenarios where the illumination and detection paths are severely distorted at the same time.展开更多
Discrete-modulated coherent-state continuous-variable quantum key distribution(DMCS-CVQKD)is of great value for its simple implementation.However,the traditional DMCS-CVQKD scheme cannot tolerate the high channel exce...Discrete-modulated coherent-state continuous-variable quantum key distribution(DMCS-CVQKD)is of great value for its simple implementation.However,the traditional DMCS-CVQKD scheme cannot tolerate the high channel excess noise and channel loss,compared to the Gaussian-modulated scheme,and its error correction is still difficult.In this paper,we propose a discrete-modulated coherent-state basis-encoding quantum key distribution(DMCS-BE-QKD)protocol,where the secret keys are encoded in the random choice of 2 measurement bases,i.e.,the conjugate quadratures X and P of discrete-modulated coherent states,and it only needs simple binary sequence error correction.We analyze the secret key rate of DMCS-BE-QKD protocol under individual and collective attacks in the linear Gaussian channel.The results show that DMCS-BE-QKD can greatly enhance the ability to tolerate the channel loss and excess noise compared to the original DMCS-CVQKD protocol,which can tolerate approximately 40 dB more channel loss compared to the original DMCS-CVQKD for the realistic value of noise.Finally,a proof-of-principle experiment is conducted under a 50.5-km optical fiber to verify the feasibility of DMCS-BE-QKD.It is based on the consistent physical procedures of the traditional DMCS-CVQKD,which makes it perfectly compatible to deployed terminals and can serve as a multiplier for the practical secure quantum cryptography communication in harsh environments.展开更多
基金financial supports from the National Natural Science Foundation of China(NSFC)(62061136005,61705141,61805152,61875129,61701321)Sino-German Research Collaboration Group(GZ 1391)+2 种基金the Mobility program(M-0044)sponsored by the Sino-German CenterChinese Academy of Sciences(QYZDB-SSW-JSC002)Science and Technology Innovation Commission of Shenzhen(JCYJ20170817095047279)。
文摘Optical cryptanalysis is essential to the further investigation of more secure optical cryptosystems.Learning-based at-tack of optical encryption eliminates the need for the retrieval of random phase keys of optical encryption systems but it is limited for practical applications since it requires a large set of plaintext-ciphertext pairs for the cryptosystem to be at-tacked.Here,we propose a two-step deep learning strategy for ciphertext-only attack(COA)on the classical double ran-dom phase encryption(DRPE).Specifically,we construct a virtual DRPE system to gather the training data.Besides,we divide the inverse problem in COA into two more specific inverse problems and employ two deep neural networks(DNNs)to respectively learn the removal of speckle noise in the autocorrelation domain and the de-correlation operation to retrieve the plaintext image.With these two trained DNNs at hand,we show that the plaintext can be predicted in real-time from an unknown ciphertext alone.The proposed learning-based COA method dispenses with not only the retrieval of random phase keys but also the invasive data acquisition of plaintext-ciphertext pairs in the DPRE system.Numerical simulations and optical experiments demonstrate the feasibility and effectiveness of the proposed learning-based COA method.
基金supported by the National Natural Science Foundation of China(Grant Nos.11634010,91850118,11774289,61675168,and 11804277)the National Key Research and Development Program of China(Grant No.2017YFA0303800)the Fundamental Research Funds for the Central Universities(Grant Nos.3102018zy036,3102019JC008,and 310201911cx022)。
文摘In recent years,metasurfaces that enable the flexible wavefront modulation at sub-wavelength scale have been widely used into holographic display,due to its prominent advantages in polarization degrees of freedom,viewing angle,and achromaticity in comparison with traditional holographic devices.In holography,the computational complexity of hologram,imaging sharpness,energy utilization,reproduction rate,and system indirection are all determined by the encoding method.Here,we propose a visible frequency broadband dielectric metahologram based on the random Fourier phase-only encoding method.Using this simple and convenient method,we design and fabricate a transmission-type geometric phase all-dielectric metahologram,which can realize holographic display with high quality in the visible frequency range.This method encodes the amplitude information into the phase function only once,eliminating the cumbersome iterations,which greatly simplifies the calculation process,and may facilitate the preparation of large area nanoprint-holograms.
基金Princess Nourah bint Abdulrahman University Researchers Supporting ProjectNumber (PNURSP2022R66), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.
文摘Authentication of the digital image has much attention for the digital revolution.Digital image authentication can be verified with image watermarking and image encryption schemes.These schemes are widely used to protect images against forgery attacks,and they are useful for protecting copyright and rightful ownership.Depending on the desirable applications,several image encryption and watermarking schemes have been proposed to moderate this attention.This framework presents a new scheme that combines a Walsh Hadamard Transform(WHT)-based image watermarking scheme with an image encryption scheme based on Double Random Phase Encoding(DRPE).First,on the sender side,the secret medical image is encrypted using DRPE.Then the encrypted image is watermarking based on WHT.The combination between watermarking and encryption increases the security and robustness of transmitting an image.The performance evaluation of the proposed scheme is obtained by testing Structural Similarity Index(SSIM),Peak Signal-to-Noise Ratio(PSNR),Normalized cross-correlation(NC),and Feature Similarity Index(FSIM).
基金National Natural Science Foundation of China(62405256)Hong Kong Research Grants Council General Research Fund(15224921,15223522,15237924)+2 种基金Hong Kong Research Grants Council Collaborative Research Fund(C5047-24G)Basic and Applied Basic Research Foundation of Guangdong Province(2023A1515010831,2025A1515011411)The Hong Kong Polytechnic University(1-CDJA,1-WZ4M).
文摘Single-pixel imaging(SPI)through complex media remains challenging.In this paper,we report high-resolution common-path SPI with dual polarization using random-frequency-encoded time sequences in complex environments where the illumination and detection paths are severely distorted.By leveraging a common-path optical configuration with orthogonal polarization states,a series of dynamic scaling factors can be corrected.The designed random-frequency encoding scheme disperses scattering-induced noise into artifacts to be simply removed.It is demonstrated in optical experiments that the proposed method is feasible and effective to reconstruct highresolution object images in complex environments.The proposed method does not require complex optical components and prior knowledge about scattering media,providing a robust solution for high-resolution optical imaging in complex scenarios where the illumination and detection paths are severely distorted at the same time.
基金supported by the Innovation Program for Quantum Science and Technology(grant no.2021ZD0300703)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)+1 种基金the Key R&D Program of Guangdong province(grant no.2020B0303040002)the National Natural Science Foundation of China(no.62101320).
文摘Discrete-modulated coherent-state continuous-variable quantum key distribution(DMCS-CVQKD)is of great value for its simple implementation.However,the traditional DMCS-CVQKD scheme cannot tolerate the high channel excess noise and channel loss,compared to the Gaussian-modulated scheme,and its error correction is still difficult.In this paper,we propose a discrete-modulated coherent-state basis-encoding quantum key distribution(DMCS-BE-QKD)protocol,where the secret keys are encoded in the random choice of 2 measurement bases,i.e.,the conjugate quadratures X and P of discrete-modulated coherent states,and it only needs simple binary sequence error correction.We analyze the secret key rate of DMCS-BE-QKD protocol under individual and collective attacks in the linear Gaussian channel.The results show that DMCS-BE-QKD can greatly enhance the ability to tolerate the channel loss and excess noise compared to the original DMCS-CVQKD protocol,which can tolerate approximately 40 dB more channel loss compared to the original DMCS-CVQKD for the realistic value of noise.Finally,a proof-of-principle experiment is conducted under a 50.5-km optical fiber to verify the feasibility of DMCS-BE-QKD.It is based on the consistent physical procedures of the traditional DMCS-CVQKD,which makes it perfectly compatible to deployed terminals and can serve as a multiplier for the practical secure quantum cryptography communication in harsh environments.
