A hybrid encryption in the optical transform domain based on public key distribution system is proposed aiming at safely deliver and management of optical encrypted system.Frist,the original image is encrypted based on optical system,and then,the work key of optical system is compressed,finally,distribution and management of the compressed key is dong by public key distribution system.In the decryption stages,the receiver do not need to wait and can obtain dencryption key in advance by means of public key distribution system.The theoretical analysis and computer simulation results show that the proposed method can solve the problem of safely deliver and management and make good use of multi-dimensional keys that encrypted system of optical transform possess.Also,this method highlight advantage of hybrid system speed.
A hybrid encryption in the optical transform domain based on public key distribution system is proposed aiming at safely deliver and management of optical encrypted system.Frist,the original image is encrypted based on optical system,and then,the work key of optical system is compressed,finally,distribution and management of the compressed key is dong by public key distribution system.In the decryption stages,the receiver do not need to wait and can obtain dencryption key in advance by means of public key distribution system.The theoretical analysis and computer simulation results show that the proposed method can solve the problem of safely deliver and management and make good use of multi-dimensional keys that encrypted system of optical transform possess.Also,this method highlight advantage of hybrid system speed.
Most of the existing selective encryption schemes are based on image processing and cannot be realized by optical structures, so their practicality is limited. Combining the optical design, a local hybrid optical encryption system based on double random phase encoding is proposed. The system proposed in this paper possesses a common aperture and dual optical path structure, which is widely used in optical design and can effectively improve the practicality of optical encryption system. First, important information and non-important information in the original image are separated by a selective beam splitter. Then light waves carrying important information enter into the 4f system for encryption, and light waves carrying non-important information enter into the diffraction system for encryption. Finally, part of the diffraction system ciphertext is replaced with 4f system ciphertext to obtain the final encrypted image. Decryption is the reverse process of encryption. First, the 4f system ciphertext is cut out from the final ciphertext. Then the 4f system ciphertext is used to restore the information replaced in the diffraction system ciphertext, thereby obtaining the complete diffraction system ciphertext. Finally, the two ciphertexts go through the reverse process of their respective systems to complete the decryption. By comparing the statistical characteristics and mean square error of the original image and the encrypted image, the effectiveness of the proposed system's encryption process is proved. By analyzing the peak signal-to-noise ratio of the original image and the decrypted image, the effectiveness of the proposed system's decryption process is proved. The sensitivity of each key of the system is analyzed to prove the security of the system. Especially the system is highly sensitive to selective encryption key, which proves the effectiveness and security of the proposed system for selective encryption. Through simulation, it is verified that the proposed system is very resistant to diffraction attacks. Even if he can obtain all the diffraction keys, the attacker still cannot obtain the selectively encrypted information. Finally, through simulation, it is verified that the proposed system has good noise resistance and crop resistance, and high robustness as well. The proposed system can realize the selective encryption through optical structure, which is safe, effective and highly robust, and thus improving the practicality of selective optical encryption system.
The optical image encryption has attracted more and more researchers’ attention, and the various encryption schemes have been proposed. In existing optical cryptosystem, the phase functions or images are usually used as the encryption keys, and it is difficult that the traditional public-key algorithm (such as RSA, ECC, etc.) is used to complete large numerical key transfer. In this paper, we propose a key distribution scheme based on the phase retrieval algorithm and the RSA public-key algorithm, which solves the problem for the key distribution in optical image encryption system. Furthermore, we also propose a novel image encryption system based on the key distribution principle. In the system, the different keys can be used in every encryption process, which greatly improves the security of the system.
An optical image encryption technique based on compressive sensing using fully optical means has been proposed. An object image is first encrypted to a white-sense stationary noise pattern using a double random phase encoding (DRPE) method in a Mach-Zehnder interferometer. Then, the encrypted image is highly compressed to a signal using single-pixel compressive holographic imaging in the optical domain. At the receiving terminal, the encrypted image is reconstructed well via compressive sensing theory, and the original image can be decrypted with three reconstructed holograms and the correct keys. The numerical simulations show that the method is effective and suitable for optical image security transmission in future all-optical networks because of the ability of completely optical implementation and substantially smaller hologram data volume.
A hybrid cryptosystem is proposed, in which one image is encrypted to two interferograms with the aid of double random-phase encoding (DRPE) and two-step phase-shifting interferometry (2-PSI), then three pairs of public–private keys are utilized to encode and decode the session keys (geometrical parameters, the second random-phase mask) and interferograms. In the stage of decryption, the ciphered image can be decrypted by wavefront reconstruction, inverse Fresnel diffraction, and real amplitude normalization. This approach can successfully solve the problem of key management and dispatch, resulting in increased security strength. The feasibility of the proposed cryptosystem and its robustness against some types of attack are verified and analyzed by computer simulations.
Aiming at the current eavesdropping security issues in the physical layer of optical networks, a new hybrid optical encryption scheme based on Highly Nonlinear Fiber (HNLF) and Super Structured Fiber Bragg Grating (SSFBG) is proposed in this paper. In the scheme, degenerate Four Wave Mixing (FWM) is used to encrypt and decrypt user information, and optical coding technology is used to encode and decode the key information. Therefore, the encoding and secret transmission of the key signal can be realized simultaneously. The security of the system is measured by comparing the waveform of the encrypted signal transmitted in the channel with the waveform of the original transmitted signal, and the effectiveness of the system is measured by the bit error rate at the system receiver side. The simulation results show that the frequency and phase of the user data information are disturbed, and the optical power of the encoded key signal is as low as -34.4 dBm. Therefore, the eavesdropping channel cannot obtain effective data information nor detect the key signal, which demonstrates the safe transmission of Quadrature Phase Shift Keying (QPSK) signal.
Public-key encryption is essential for secure communications, eliminating the need for pre-shared keys. However, traditional schemes such as RSA (Rivest-Shamir-Adleman) and elliptic curve cryptography rely on computational complexity, making them increasingly susceptible to advances in computing power and algorithms. Physical-layer encryption, which leverages the intrinsic properties of physical systems, offers a promising alternative with security rooted in physics. Despite progress in this field, public-key encryption at the optical layer remains largely unexplored. Here, we propose a novel optical public-key encryption scheme based on partially coherent light sources. The cryptographic keys are encoded in the incoherent optical transmission matrix of an on-chip Mach-Zehnder interferometer mesh, providing high complexity and resilience to computational attacks. We experimentally demonstrate encrypted image transmission over 40 km of optical fiber with high decryption fidelity and achieve a 10 Gbit/s optical encryption rate using a lithium niobate photonic chip. This represents the first implementation of public-key encryption at the physical optical layer. The approach offers key advantages in security, cost, energy efficiency, and compatibility with commercial optical communication systems. By integrating public-key encryption into photonic hardware, this work opens a new direction for secure and high-speed optical communications in next-generation networks.