Digital optics, digital holography, and optical encryption (original) (raw)
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Optics & Laser Technology, 2010
A digital holographic information system can process complex three-dimensional (3-D) object information. We demonstrate a scheme for securing complex and 3-D information in the context of in-line digital holography. Double random phase encoding in the free-space propagation domain of light is used to secure the complex information. Encrypted in-line digital holograms are recorded using the position-phase-shifting method. The encrypted complex image at the CCD recording plane is retrieved from the real-valued digital holograms, and is used for decryption. The robustness of the method has also been studied for various securing keys used in the method against blind decryption. A layer-bylayer information retrieval from the encrypted digital hologram is also discussed. The method can also be used to secure digital complex information in a virtual optics modality using holographic principles.
Securing of Two and Three Dimensional Information Based on In-line Digital Holography
2000
A method that combines the high speed of digital encryption and the high security of optical encryption with the advantages of electronic transmission, storage, and decryption is introduced. The encryption is performed by use of multi-dimensional lock on the hologram plan, providing high security in the encrypted image and a key with many degrees of freedom. We described how our
Holographic Data Encryption and Decryption Techniques- literature survey (2001)
This report is to summarize the literature search conducted so far on holographic data encryption techniques. The search indicates three major streams: the amplitude and phase random mask encoded, phase contrast and digital holography techniques. Other techniques outside those three streams are briefly reviewed next. Brief discussion and comments in comparison of the searched methods with the optical scanning method are also presented. In conclusion no prior method has been reported to be carried out using optical scanning holography technique. (note: survey conducted on 2001)
Image encryption based on pure intensity random coding and digital holography technique
Optik - International Journal for Light and Electron Optics, 2003
We propose a novel image encryption method that combines the pure intensity random encoding and the digital holography technique. A phase-shifting interferometer records both phase and amplitude information of a complex object with a CCD sensor array. The encryption is performed by placing two pure intensity random masks between the image to be encrypted and an intensity recording device. Electronic decryption can be performed with fast Fresnel reconstruction procedure. Numerical simulation results show the validity of the algorithm and an optoelectronic implementation setup is also presented.
Phase-to-amplitude data page conversion for holographic storage and optical encryption
Applied Optics, 2007
A new phase-to-amplitude data page conversion method is proposed for efficient recovery of the data encoded in phase-modulated data pages used in holographic storage and optical encryption. The method is based on the interference between the data page and its copy shifted by an integral number of pixels. Key properties such as Fourier plane homogeneity, bit error rate, and positioning tolerances are investigated by computer modeling, and a comparison is provided with amplitude-modulated data page holographic storage with and without static phase masks. The feasibility and the basic properties of the proposed method are experimentally demonstrated. The results show that phasemodulated data pages can be used efficiently with reduced system complexity.
Securing information by use of digital holography
Optics Letters, 2000
An information security method that uses a digital holographic technique is presented. An encrypted image is stored as a digital hologram. The decryption key is also stored as a digital hologram. The encrypted image can be electrically decrypted by use of the digital hologram of the key. This security technique provides secure storage and data transmission. Experimental results are presented to demonstrate the proposed method.
Low photon count based digital holography for quadratic phase cryptography
Optics letters, 2017
Recently, the vulnerability of the linear canonical transform-based double random phase encryption system to attack has been demonstrated. To alleviate this, we present for the first time, to the best of our knowledge, a method for securing a two-dimensional scene using a quadratic phase encoding system operating in the photon-counted imaging (PCI) regime. Position-phase-shifting digital holography is applied to record the photon-limited encrypted complex samples. The reconstruction of the complex wavefront involves four sparse (undersampled) dataset intensity measurements (interferograms) at two different positions. Computer simulations validate that the photon-limited sparse-encrypted data has adequate information to authenticate the original data set. Finally, security analysis, employing iterative phase retrieval attacks, has been performed.
Exact solution to simultaneous intensity and phase encryption with a single phase-only hologram
Optics Letters, 2013
A phase-only hologram applies a modal transformation to an optical transverse spatial mode via phase encoding and intensity masking. Accurate control of the optical field crucially depends on the method employed to encode the hologram. In this Letter, we present a method to encode the amplitude and the phase of an optical field into a phase-only hologram, which allows the exact control of spatial transverse modes. Any intensity masking method modulates the amplitude and alters the phase of the optical field. Our method consists in correcting for this unwanted phase alteration by modifying the phase encryption accordingly. We experimentally verify the accuracy of our method by applying it to the generation and detection of transverse spatial modes in mutually unbiased bases of dimension two and three.