A method is proposed for constructing a cryptographic hash function based on the interaction between linearly polarized light and multiple-scattering media in a parallel fashion. It is well known that an unpredictable noise-like speckle pattern will appear when a light beam passes through a scattering medium. By leveraging this natural optical-encoding mechanism, we developed a paralleled algorithm to construct an optical hash function. It was shown by numerical simulation to have a high security level. Furthermore, in the proposed conceptual optical-digital setup, a strategy for multiplexing linearly polarized light was introduced to accelerate data processing.
A method is proposed for constructing a cryptographic hash function based on the interaction between linearly polarized light and multiple-scattering media in a parallel fashion. It is well known that an unpredictable noise-like speckle pattern will appear when a light beam passes through a scattering medium. By leveraging this natural optical-encoding mechanism, we developed a paralleled algorithm to construct an optical hash function. It was shown by numerical simulation to have a high security level. Furthermore, in the proposed conceptual optical-digital setup, a strategy for multiplexing linearly polarized light was introduced to accelerate data processing.
Data proliferation in the digital age necessitates robust encryption techniques to protect information privacy. Optical encryption leverages the multiple degrees of freedom inherent in light waves to encode information with parallel processing and enhanced security features. However, implementations of large-scale, high-security optical encryption have largely remained theoretical or limited to digital simulations due to hardware constraints, signal-to-noise ratio challenges, and precision fabrication of encoding elements. Here, we present an optical encryption platform utilizing scattering multiplexing ptychography, simultaneously enhancing security and throughput. Unlike optical encoders which rely on computer-generated randomness, our approach leverages the inherent complexity of light scattering as a natural unclonable function. This enables multi-dimensional encoding with superior randomness. Furthermore, the ptychographic configuration expands encryption throughput beyond hardware limitations through spatial multiplexing of different scatterer regions. We propose a hybrid decryption algorithm integrating model- and data-driven strategies, ensuring robust decryption against various sources of measurement noise and communication interference. We achieved optical encryption at a scale of ten-megapixel pixels with 1.23 µm resolution. Communication experiments validate the resilience of our decryption algorithm, yielding high-fidelity results even under extreme transmission conditions characterized by a 20% bit error rate. Our encryption platform offers a holistic solution for large-scale, high-security, and cost-effective cryptography.
We report a novel optical encryption strategy that utilizes highly scattered wavefront of light field to encrypt the plaintext and exploits a scattering medium as the unique physical key. For information decryption, an imaging technique based on the speckle-correlation scattering matrix is adopted to directly extract the wavefront information from speckles, i.e., the ciphertext. The decryption relies on the transmission matrix of the scattering medium which serves as the unique key. In particular, different parts of a scattering medium have absolutely different TMs. Thus, even if attackers get the cryptosystem and repeat the measurement process, they cannot recover the key without knowing the exact part of the medium we used. The security of this scheme is further guaranteed by the advantage that data cannot be leaked without a large percentage (>60%) of the key eavesdropped. In addition, its feasibility and advantage are demonstrated experimentally.
An approach for constructing an optical Hash function, also known as a one-way cryptosystem, based on two-beam interference (OHF-TBI) is proposed. The purpose of this method is creating the "digital fingerprint" of any precoding message with arbitrary length. This approach consists of three steps, in which the main step is a one-way processing procedure with a compression mechanism. To achieve the function of one-way property and compressibility, we designed a cascaded process on the basis of the two-beam interference principle and phase-truncation operation. The performance of the mentioned OHF-TBI is verified by theoretical analysis and a set of numerical simulations.
Random number generators (RNG) are fundamental to cryptographic systems, requiring high entropy, unpredictability, and resistance to cloning attacks. This work proposes RNG based on optical physical unclonable function (PUF) that uses random scattering of structured vortex beams through rough surface. The inherent disorder of the scattering medium with tunable beam parameters like vortex order, provides a rich source of physical randomness. The generated speckle patterns are processed using a post processing algorithm to produce random sequences at a rate of 1.42 Gbps. The statistical quality of the sequences is evaluated using the NIST SP 800-22, AIS-31, and Dieharder test suites, which meet the required randomness criteria. Further assessment using entropies and Kolmogorov complexity shows high entropy and algorithmic randomness. The physical unclonability and uniqueness are verified through inter-device hamming distances, Pearson correlation of sequences obtained from different spatial regions and vortex orders, revealing negligible correlations. To assess resilience against data based adversaries, machine learning modeling attacks are performed. The prediction accuracies remain close to random guessing, showing resistance to learning based cloning and response prediction attacks. These results establish the proposed optical PUF method as a high speed, physically unclonable, and machine learning resistant source of random numbers for secure cryptographic applications.
Abstract Optical encryption is an emerging technique that uses optical systems to securely encode and decode information for data transmission. In this study, we present an integrated optical encryption platform that consists of a scattering-augmented ptychographic encryption system, a transmission-efficient compressive sampling strategy, and a high-capacity decryption algorithm based on a hybrid model-data driven approach. Our encryption system leverages random light scattering as a physical unclonable function, enabling the encoding of complex object wavefronts with high optical throughput. In contrast to traditional encoders that offer insecure pseudo-randomness, the light scattering process ensures true randomness in the reported platform. To optimize transmission efficiency, we implement a compressive sampling strategy that reduces data transmission volume by at least one order of magnitude. Moreover, we devise a decryption algorithm that merges model-driven optimization with data-driven deep learning, effectively addressing the highly underdetermined retrieval task and providing robust decryption against various measurement noise and communication interference. The efficacy of our system is corroborated by an integrated optical prototype capable of encrypting ten million of pixels within minutes. Communication experiments confirm the resilience of our decryption algorithm, which retrieves high-fidelity results even under extreme transmission conditions characterized by a 20% bit error rate. Our innovative encryption technique presents a comprehensive solution for high-capacity data transmission, fortified by scattering-augmented security.
Although quantum key distribution (QKD) provides information-theoretically secure keys, a significant gap exists between its relatively low key generation rate and the high-speed demands of classical optical communication. To address this challenge, this paper proposes a stream cipher encryption scheme based on QKD and Secure Hash Algorithm 256 (SHA-256). Core to the scheme is an innovative group-wise dual-randomized affine construction. Integrated with configurable grouping and parallel processing, this mechanism applies a linear mapping defined by dynamic initial vectors (IV) and variable full-domain strides to each data group. This approach achieves deep orthogonalization of the hash input space while preserving architectural parallelism. Simulation results demonstrate that the scheme achieves high-strength security protection while ensuring real-time performance of the communication link. Specifically, statistical analysis confirms that the ciphertext exhibits high entropy and negligible autocorrelation, alongside high key sensitivity. The scheme expands the computational search space beyond the conventional 2 256 bound, effectively countering pre-computation attacks.