Double Random Phase Research Articles

A color image encryption scheme reducing the correlations between R, G, B components

In this paper, a new color image encryption method based on confusion and diffusion processes has been introduced. A chaotic system based sub-block image swapping has been proposed in order to permutate the positions of the pixels as a confusion method. Moreover, the pixels in sub-block have been spirally shifted to increase the confusion level. Modulo and XOR operations which are based on a chaotic system have been suggested in order to transform the values of the pixels as a diffusion method. To do that, each pixel value is XORed with the next pixel and then modulo operation has been performed for the current and next pixels throughout the image. Double Random Phase Encoding (DRPE) method is also utilized as an optical setup in this study. In addition, an algorithm is suggested in order to reduce the correlations between R, G, B components of the color image. The security analyses performing histogram analysis, correlation coefficient analysis of two adjacent pixels, information entropy analysis, chi-squared test and differential attack have been carried out in order to show that the proposed algorithm scheme is robust against differential, statistical and exhaustive attacks. Moreover, secret key sensitivity, initial condition sensitivity, cropping attack, noise test and plaintext attacks have been done to evaluate the performance of the introduced algorithm. All analysis results have been carried out in MATLAB environment.

An efficient DNA-inspired image encryption algorithm based on hyper-chaotic maps and wavelet fusion

This paper introduces an efficient image encryption method which is inspired by Deoxyribo Nucleic Acid (DNA) nitrogenous bases. Amongst its advantages is that it is highly sensitive to many types of attacks. A confused version of an image (using a simple chaotic map) is DNA coded using its four types of nitrogenous bases. The resultant image made of DNA sequences is transformed into four sub-images A, C, G, and T, DNA’s bases. Chen’s hyper-chaotic map is used to diffuse the resultant images, according to a control code. The four DNA images are then combined using a wavelet confusion algorithm to produce an encrypted image. Numerical simulation was used to examine the effectiveness of the encrypted image against different attacks. The results were compared to those of other encryption algorithms and proved that the proposed encryption method delivers better results than other conventional ones including DNA based with different chaotic maps and double random phase encoding.

Multi-image and color image encryption via multi-slice ptychographic encoding

Multi-slice ptychography is a diffractive imaging technique that can reconstruct the information of a 3-D object from its diffraction intensities. In this article, we propose a multi-slice ptychographic encoding method for the encryption of multiple and color images. Full-phase images to be encrypted together with inserted phase keys are transformed into diffraction intensities (i.e., cipher texts) via multi-slice ptychographic encoding and double random phase encoding. The multi-slice ptychographic encoding refers to the process of using ptychographic scanning and recording to encrypt a multi-slice object that is composed of secret images and inserted phase keys. During decryption, an iterative phase retrieval algorithm is modified. The feasibility, robustness and security of the proposed method are analyzed. Numerical simulation results show that the proposed method can achieve high-quality decryption, and has high security and robustness against noise, compression, and occlusion.

Cancelable Iris template for secure authentication based on random projection and double random phase encoding

Biometric recognition approaches have overwhelmed major issues in traditional authentication systems. Privacy invasion and security are the needed features in the effective development of biometric recognition systems. Recently some biometric techniques have been suffered to hacking trails also. Hence there is a despairing need to propose a novel cancelable iris recognition scheme. The prime objective of this research is to create a transformed cancelable biometric template through an encryption function and a one-way transformation function. The random projection matrix is employed here to generate the first feature vector. Then an encrypted cancelable iris code is generated using Double Random Phase Encryption (DRPE) in the Fractional Fourier Transform (FFT) domain. The proposed framework utilizes both the left and right iris image of a person and generates a single cancelable iris template. This feature guarantees the privacy-preserving cancelable iris code generation for secure authentication. The experiment is carried on two state-of-art datasets CASIA Iris V4 and IITD iris to affirm the efficacy of the proposed methodology. The result analysis witnessed a promising accuracy of 99.59%, a recognition rate of 99.88% with a lower Equal Error Rate (ERR) of 0.46%. It has also been proved that the proposed approach is computationally efficient as it recognizes the iris code with less recognition time of 7 ms with a maximum true positive and true negative rate of 100%.

Equivalence analysis of highly scattering process and double random phase encryption process

The scattering system through a highly scattering thin layer only affects the amplitude and phase distribution of incident light wave, but does not lead the total energy to be attenuated. This process can be regarded as a process that light wave is encoded by the scattering medium, which is similar to a double random phase encryption system. In this paper, firstly, it is proved that the distribution characteristics of speckle generated by the light wave carrying the target information through a strongly scattering thin layer are highly similar to the distribution characteristics of cyphertext obtained by the double random phase encryption system encrypting the same plaintext target. Therefore, the scattering system is seen as a double random phase encryption system, and the two random phase keys corresponding to the scattering system are calculated accurately by using the phase recovery algorithm. At the same time, it is proved that these two key boards can successfully reconstruct the original images corresponding to any other speckles obtained by the scattering system. Finally, a cyphertext-only attack method to attack a scattering system through a highly scattering thin layer is used to further prove the equivalence of two key boards and the good results are obtained. Since imaging through a scattering medium is an extremely complicated process, we actually simplify the corresponding process ideally. It should be noted that the equivalent system means that the incident-surface-to-exit-surface of scattering medium is equivalent to the incident-surface-to-exit-surface of DRPE system. However, in the actual process, there are still two diffraction processes: one is the diffraction process from the object to the incident surface and the other is the diffraction process from the output surface to the receiving surface. These two diffraction processes will cause the incident image and the output image of scattering medium to have a certain diffraction effect. We believe that under ideal conditions, due to the equivalence between the thin-layer strong scattering system and the DRPE system, theoretically all pure ciphertext attack methods applicable to the DRPE system can be applied to the speckle recovery of the thin-layer strong scattering system. In the future, it is possible to develop more methods of using system equivalence to crack the scattered light field. We hope this article can provide a new idea for scattering imaging.

Sparse Matrix Based Low-Complexity, Recursive, and Radix-2 Algorithms for Discrete Sine Transforms

This paper presents factorizations of each discrete sine transform (DST) matrices of types I, II, III, and IV into a product of sparse, diagonal, bidiagonal, and scaled orthogonal matrices. Based on the proposed matrix factorization formulas, reduced multiplication complexity, recursive, and radix-2 DST-I/II/III/IV algorithms are presented. We will present the lowest multiplication complexity DST-IV algorithm in the literature. The paper fills a gap in the self-recursive, exact, and radix-2 DST-I/II/III algorithms executed via diagonal, bidiagonal, scaled orthogonal, and simple matrix factors for any input n = 2t (t ≥ 1). The paper establishes a novel relationship between DST-II and DST-IV matrices using diagonal and bidiagonal matrices. Similarly, a novel relationship between DST-I and DST-III matrices is proposed using sparse and diagonal matrices. These interweaving relationships among DST matrices enable us to bridge the existing factorizations of the DST matrices with the proposed factorization formulas. We present signal flow graphs to provide a layout for realizing the proposed algorithms in DST-based integrated circuit designs. Additionally, we describe an implementation of algorithms based on the proposed DST-II and DST-III factorizations within a double random phase encoding (DRPE) image encryption scheme.

Three-Dimensional Photon Counting Optical Encryption With Enhanced Visual Quality and Security Level

In this paper, we propose three-dimensional (3D) photon counting double random phase encryption (DRPE) with enhanced visual quality and security level. Conventional 3D photon counting DRPE can quickly encrypt the data by using the 4f optical system and random phase masks with enhanced security because the 3D photon counting technique is used. 3D photon counting DRPE extracts photons from the encrypted data by using statistical methods such as the Poisson random process, and the visual quality of the decrypted data can be enhanced through the 3D reconstruction process. However, it still has a problem to visualize the data when we extract extremely a few photons. To improve the security and the visual quality of the decrypted data, we propose the random amplitude reconstruction process in the encryption stage. Our proposed method reconstructs the amplitude of the encrypted data at a random depth. Thus, the shifting pixel value and depth information can be another important key for decryption through the random process. Therefore, it can effectively decrypt data securely, and the visual quality of the decrypted data can be enhanced. Finally, through the random reconstruction process in the decryption stage, our proposed method can simultaneously enhance the security and visual quality. To verify our proposed method, we carry out the simulation and optical experiment.

Privacy-Preserving Image Classification With Deep Learning and Double Random Phase Encoding

With the emergence of cloud computing, large amounts of private data are stored and processed in the cloud. On the other hand, data owners (users) may not want to reveal data information to cloud providers to protect their privacy. Therefore, users may upload encrypted data to the cloud or third-party platforms, such as Google Cloud, Amazon Web Service, and Microsoft Azure. Conventionally, data must be decrypted before being analyzed in the cloud, which raises privacy concerns. Moreover, decryption of big data such as images requires enormous computation resources, which is unsuitable for energy-constrained devices, particularly Internet of Things (IoT) devices. Data privacy in most popular applications, such as image query or classification, can be preserved if encrypted images can be directly classified on the cloud or IoT devices without decryption. This paper proposes a high-speed double random phase encoding (DRPE) technique of encrypting images into white-noise images. DRPE-encrypted images are then uploaded and stored in the cloud. Images that are encrypted without being decrypted are classified using deep convolutional neural networks in the cloud. The simulation results indicated the feasibility and good performance of the proposed approach. The proposed privacy-preserving image classification method can be useful in data-sensitive fields, such as medicine and transportation.

Deep-learning-based ciphertext-only attack on optical double random phase encryption

Optical cryptanalysis is essential to the further investigation of more secure optical cryptosystems. Learning-based attack 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 attacked. Here, we propose a two-step deep learning strategy for ciphertext-only attack (COA) on the classical double random 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.

Efficient Three-Dimensional Video Cybersecurity Framework Based on Double Random Phase Encoding

With the rapidly increasing rate of using online services and social media websites, cybercriminals have caused a great deterioration in the network security with enormous undesired consequences. Encryption techniques may be ... | Find, read and cite all the research you need on Tech Science Press

Medical image encryption based on biometric keys and lower–upper decomposition with partial pivoting

The security of medical image transmission in telemedicine is very important to patients' privacy and health. A new asymmetric medical image encryption scheme is proposed. The medical image is encrypted by two spiral phase masks (SPM) and the lower-upper decomposition with partial pivoting, where the SPM is generated from the iris, chaotic random phase mask, and amplitude truncated spiral phase transformation. The proposed scheme has the following advantages: First, the iris is used for medical image encryption, which improves the security of the encryption scheme. Second, the combination of asymmetric optical encryption and three-dimensional Lorenz chaos improves the key space and solves the linear problem based on double-random phase encoding. Third, compared with other encryption schemes, the proposed scheme has advantages in occlusion attacks, key space, correlation, and information entropy. Numerical simulation and optical results verify the feasibility and robustness of the encryption scheme.

Exploiting optical chaos for double images encryption with compressive sensing and double random phase encoding

Images as a common information carrier are widely disseminated and used at present, meanwhile, image security and privacy protection are also facing severe tests. To enhance the security of images, an asymmetric double color images cryptosystem introduced optical chaos technology is proposed based on compression sensing (CS) and double random phase encoding (DRPE). It is the first time that the combination of CS, DRPE and optical chaos technology is demonstrated to the best of our knowledge. By means of the optical chaos keys generated by a constructed optical chaos model, the two color images are first decomposed into their respective Red–Green–Blue (RGB) channels, CS based on discrete wavelet transform is then performed for the first encryption. Afterwards, the second encrypion of DRPE in fractional Fourier transform domain (FrFT) with optical chaos technology is also used, and the asymmetric encryption by carrying out equal modulus decomposition (EMD) with optical chaos keys further enhance the security finally. Simulation results and security analysis confirm that the cryptosystem owns multi-layer protection and adequate resistance to brute-force attack, statistical attack, differential attack, noise attack and chosen-plaintext attack, which is efficient and capable of guaranteeing the security of images and can provide an alternative solution for image security and privacy protection.

Security analysis and modified attack algorithms for a nonlinear optical cryptosystem based on DRPE

In this paper, security of a nonlinear optical cryptosystem based on double random phase encoding (DRPE) is analyzed. In the cryptosystem, a time-varying nonlinear term is combined with the classical DRPE technique to enhance security. The advantages of the nonlinear term are its easy distribution and no effect on the decrypted image. Also, it is confirmed that the method is resistant to conventional plaintext attacks such as known-plaintext attack, chosen-plaintext attack, and ciphertext only attack. However, our security analysis shows that the method is vulnerable to the modified chosen-plaintext, and known-plaintext attacks. The original image can be recovered successfully using the proposed attack algorithms. Numerical simulation results are presented to validate the proposed attack methods and test effectiveness of our analysis.

A temporal phase-truncated double random phase encoding cryptosystem in the temporal skew Fourier transform domain

A temporal phase-truncated double random phase encoding cryptosystem is proposed to be improved by replacing the temporal Fourier transformers (TFTs) of the dispersion-time lens-dispersion structure with temporal skew Fourier transformers (TSFTs). A TSFT is similar to a TFT except for the time lens (TL) replaced by a skew time lens (STL). A STL is a temporal analog of a spatial cylindrical lens with the in-plane rotational asymmetry mapping to a front–back asymmetry. The front–back asymmetry is achieved by adding the chirp factor C of a TL by +ϵ⋅C and −ϵ⋅C respectively along the positive and negative half axis of the local time coordinate. The skew coefficients ϵ1 and ϵ2 of the two TSFTs involved in the encryption stage are dimensionless and ideally unbounded, serving as additional secret keys. By mathematical analysis, STLs are proven to have complex-value modulations on low frequency components of input signals of TSFTs, which cannot be removed by phase truncations (PTs) in the legal decryption stage. The plain/cipher-text-independent and non-removability features of STLs make phase retrieval attacks unable to exempt eavesdroppers from brute-force trials of STLs. A STL is implemented by an electrical arbitrary waveform generator (AWG) driven electro-optic phase modulator (EOPM). By numerical simulations, the using of STLs is proven to increase the difficulty of phase retrieval attacks in terms of the time consuming required for convergence. Even if phase retrieval attacks converge, the plaintext signal cannot be recovered without the knowledge of ϵ1,2 in the encryption stage. The total key space of ϵ1,2 is also evaluated as 217 at AWG bandwidth Bm=20 GHz, and as 237 at Bm=100 GHz. The fidelity robustness of our optical cryptosystem against possible noise and occlusion penalties on the communication channels and networks of optical cipher-text signals is also proven.

A novel 1D chaotic system for image encryption, authentication and compression in cloud

To solve the privacy image problem stored in cloud, we propose a compressive sensing (CS) based image compression, authentication, encryption algorithm in cloud, which can implement computation outsourcing to get rid of the expensive storage and computation costs. To achieve these goals, combined with the logistic-tent-sine chaotic map, a logistic-tent-sine chaotic map (LTSS) is proposed for it has larger chaotic ranges and better chaotic behaviors than simple 1D chaotic map such as a logistic chaotic map. Then, the LTSS chaotic system is employed for image protection algorithm in cloud, which contains three parts: data owner, cloud services and data user. The primary role of the data owner part is to compress and encrypt the image while embedding the owner’s Palmprint discriminative and binary features for authentication. The low-frequency part of the image is encrypted using the proposed Binary Data Cyclic Encryption algorithm (BDCE) while the owner’s palmprint features are embedded for authentication of the data owner. The high-frequency data are randomized for compression by the CS and following encrypted by the Double Random Phase Encoding (DRPE). For the cloud services, authentication services depend on the key and palmprint features and the high computational compressed sensing reconstruction is implemented in cloud can reduce the user burden. For data users, a user should provide the correct key and right palmprint, and then obtain an image available from the cloud service. The algorithm has better quality compared with the common compressive sensing based algorithms and robust to noise and occlusion for using the discrete wavelet transform. What is more, theoretical analysis and empirical evaluations show that the proposed algorithm can resist to exhaustive attack, differential attack and classical attacks.

Image compression-encryption algorithm based on 2D compressive sensing and double random phase encoding

In this paper, an image compression and encryption algorithm based on 2D compressive sensing and double random phase encoding is proposed. Compared with traditional encryption algorithms, 2D compressive sensing can realize image compression and encryption at the same time, with high execution efficiency. Double random phase encoding can not only realize image encryption fast, but also has robustness. Moreover, combining 2D compressive sensing with double random phase encoding can obtain better encryption security. Simulation results show that this algorithm has better image compression performance, and can ensure security and robustness.

Optical multimodal biometric encryption that uses digital holography

In this paper, we propose an optical multimodal biometric encryption technique which uses digital holography (DH) for multiple biometric recording and successive optical encryption methods, by means of keys generated from biometric data. Physiological biometrics, such as fingerprints or iris scans, along with behavioral biometrics such as voice, are recorded simultaneously as multimodal biometrics, using multi-parameter off-axis DH. Moreover, multiple biometrics embedded in the same holograms are encrypted using the Fresnel domain double random phase encoding method, in which keys are generated from biometric data via a phase retrieval algorithm. By employing the decryption procedure for this encoding method, along with the correct keys and reconstruction parameters of DH, the original multimodal biometrics can be successfully retrieved . The proposed method provides multimodal biometrics with a higher level of security by availing itself of the advantages of optical techniques. Our proposed multimodal biometric security scheme is demonstrated and validated by the results of the optical recording and encryption of biometric data presented below.

Analysis of triple random phase encoding cryptosystem in Fresnel domain

In this paper, a triple random phase encryption scheme in the Fresnel domain is presented in a 4f system. The scheme is an extension of the double random phase encoding scheme in the Fresnel domain. Firstly, the image is subjected to double random phase encoding in the Fresnel domain and thereafter, another random phase mask is bonded with it. The scheme is validated for grayscale and binary images. Cryptosystem is exposed to statistical attack in the form of histogram, 3-D plots and information entropy, and results reveal that scheme endures these statistical attacks. The sensitivity of the Fresnel parameters to their original values is also shown in the figures. A comparative analysis also performed to demonstrate that the proposed scheme is effective and provides enhanced security against known-plaintext and chosen-ciphertext attack as compared to double random phase encoding method in Fresnel domain.

Optical image encryption based on quantum walks

In this paper, we propose a new optical encryption approach based on quantum walks and double random phase encoding technique. Quantum walks have been proven as an excellent tool for designing modern cryptographic mechanisms due to its ability to resist probable attacks from both digital and quantum computers. In the proposed approach, we use the alternate quantum walks (AQW) at two encryption stages. First, inner encryption and encoding by double random phase encoding (DRPE) which executed using permutation followed by substitution. Furthermore, AQW is adapted to generate two random masks for the DRPE process. Simulation-based validation of our proposed technique, including correlation, histogram, sensitivity, key space as well as noise and data loss analysis provide impetus to consider its use in applications in modern optical cryptosystems.

Security-enhanced optical cryptosystem using nonergodic scrambling phase mask.

Cryptanalysis revealed a security flaw in the double random phase encoding (DRPE) system, and the original image was recovered via a ciphertext-only attack. In this paper, a nonergodic scrambling phase mask (NESPM) is designed, and a security-enhanced cryptosystem is established by replacing the bonded random phase mask (RPM) in the DRPE system with the designed NESPM. The original image in the security-enhanced cryptosystem is optically scrambled at "macropixel" level by the bonded NESPM, instead of being diffused by the RPM, as in the DRPE system. Due to such a scrambling operation, the ergodic property of the Fourier-plane speckle pattern in the designed cryptosystem is removed, and the original image cannot be recovered via the attack. Experimental results demonstrate that the designed cryptosystem is resistant to the attack. Security enhancement is achieved.