Manuscript received April 14, 1983; revised June 24, 1983. N. B. Abraham is with the Department of Physics, BrynMawr College, Bryn Mawr, PA 19010. P. Mandel is with the Service de Chimie Physique 11, Universite Libre de Bruselles, Brussels, Belgium. L. W. Casperson is with the Department of Electrical Engineering and Applied Science: University of California, Los Angeles, CA 90024. Editor’s Note: A similar correction by Dr. F. Holigner and Prof. Dr. H. Weber of the Universitat Kaiserslautern was received on May 4, 1983. tions can be expressed as BR = y + p P (3a j

Principles of lasers

Authentication is an essential cryptographic primitive that confirms the identity of parties during communications. For security, it is important that these identities are complex, in order to make them difficult to clone or guess. In recent years, physically unclonable functions (PUFs) have emerged, in which identities are embodied in structures, rather than stored in memory elements. PUFs provide “digital fingerprints,” where information is usually read from the static entropy of a system, rather than having an identity artificially programmed in, preventing a malicious party from making a copy for nefarious use later on. Many concepts for the physical source of the uniqueness of these PUFs have been developed for multiple different applications. While certain types of PUF have received a great deal of attention, other promising suggestions may be overlooked. To remedy this, we present a review that seeks to exhaustively catalogue and provide a complete organisational scheme towards the suggested concepts for PUFs. Furthermore, by carefully considering the physical mechanisms underpinning the operation of different PUFs, we are able to form relationships between PUF technologies that previously had not been linked and look toward novel forms of PUF using physical principles that have yet to be exploited.

A PUF taxonomy

Shaping the flow of light at the nanoscale has been a grand challenge for nanophotonics over decades. It is now widely recognized that metasurfaces represent a chip-scale nanophotonics array technology capable of comprehensively controlling the wavefront of light via appropriately configuring subwavelength antenna elements. Here, we demonstrate a reconfigurable metasurface that is multifunctional, i.e., notionally capable of providing diverse optical functions in the telecommunication wavelength regime, using a single compact, lightweight, electronically controlled array with no moving parts. By electro-optical control of the phase of the scattered light from each identical individual metasurface element in an array, we demonstrate a single prototype multifunctional programmable metasurface that is capable of both dynamic beam steering and reconfigurable light focusing. Reconfigurable multifunctional metasurfaces with arrays of tunable optical antennas thus can perform arbitrary optical functions by programmable array-level control of scattered light phase, amplitude, and polarization, similar to dynamic and programmable memories in electronics.

/pdf/electro-optically-tunable-multifunctional-metasurfaces-5a5bfcbvnb.pdf

Electro-optically Tunable Multifunctional Metasurfaces.

Radio frequency identification (RFID) is a technology that enables RFID readers to perform fully automatic wireless identification of objects that are labeled with RFID tags. Initially, this technology was mainly used for electronic labeling of pallets, cartons, and products to enable seamless supervision of supply chains. Today, RFID technology is widely deployed to many other applications as well, including animal and product identification [2, 42], access control [2, 47], electronic tickets [47] and passports [27], and even human implantation [30].

Enhancing RFID Security and Privacy by Physically Unclonable Functions (Extended Abstract)

Blockchain is emerging as a promising candidate for the uberization of Internet services It is a decentralized, secure, and auditable solution for exchanging, and authenticating information via transactions, without the need of a trusted third party Therefore, blockchain technology has recently been integrated with industrial Internet-of-things (IIoT) networks to help realize the fourth industrial revolution, Industry 40 Though blockchain-enabled IIoT networks may have the potential to support the services and demands of next-generation networks, the gap analysis presented in this work highlights some of the areas that need improvement Based on these observations, the article then promotes the utility of reinforcement learning (RL) techniques to address some of the major issues of blockchain-enabled IIoT networks such as block time minimization and transaction throughput enhancement This is followed by a comprehensive case study where a Q-learning technique is used for minimizing the occurrence of forking events by reducing the transmission delays for a miner Extensive simulations have been performed and the results have been obtained for the average transmission delay which relates to the forking events The obtained results demonstrate that the Q-learning approach outperforms the greedy policy while having a reasonable level of complexity To further develop the blockchain-enabled IIoT networks, some future research directions are also documented While this article highlights the applications of RL techniques in blockchain-enabled IIoT networks, the provided insights and results could pave the way for rapid adoption of blockchain technology

https://www.mdpi.com/2071-1050/12/12/5161/pdf

Reinforcement Learning in Blockchain-Enabled IIoT Networks: A Survey of Recent Advances and Open Challenges

Physical unclonable functions are the physical equivalent of one-way mathematical transformations that, upon external excitation, can generate irreversible responses. Exceeding their mathematical counterparts, their inherent physical complexity renders them resilient to cloning and reverse engineering. When these features are combined with their time-invariant and deterministic operation, the necessity to store the responses (keys) in non-volatile means can be alleviated. This pivotal feature, makes them critical components for a wide range of cryptographic-authentication applications, where sensitive data storage is restricted. In this work, a physical unclonable function based on a single optical waveguide is experimentally and numerically validated. The system's responses consist of speckle-like images that stem from mode-mixing and scattering events of multiple guided transverse modes. The proposed configuration enables the system's response to be simultaneously governed by multiple physical scrambling mechanisms, thus offering a radical performance enhancement in terms of physical unclonability compared to conventional optical implementations. Additional features like physical re-configurability, render our scheme suitable for demanding authentication applications.

/pdf/physical-unclonable-function-based-on-a-multi-mode-optical-2ez2ghhofs.pdf

Physical Unclonable Function based on a Multi-Mode Optical Waveguide.

Data centers are continuously growing in scale and can contain more than one million servers spreading across thousands of racks; requiring a large-scale switching network to provide broadband and reconfigurable interconnections of low latency. Traditional data center network architectures, through the use of electrical packet switches in a multi-tier topology, has fundamental weaknesses such as oversubscription and cabling complexity. Wireless intra-data center interconnection solutions have been proposed to deal with the cabling problem and can simultaneously address the over-provisioning problem by offering efficient topology re-configurability. In this work we introduce a novel free space optical interconnect solution for intra-data center networks that utilizes 2D optical beam steering for the transmitter, and high bandwidth wide-area photodiode arrays for the receiver. This new breed of free space optical interconnects can be developed on a photonic integrated circuit; offering ns switching at sub-μW consumption. The proposed interconnects together with a networking architecture that is suitable for utilizing those devices could support next generation intra-data center networks, fulfilling the requirements of seamless operation, high connectivity, and agility in terms of the reconfiguration time.

https://www.mdpi.com/2304-6732/5/3/21/pdf

Free Space Intra-Datacenter Interconnects Based on 2D Optical Beam Steering Enabled by Photonic Integrated Circuits

In this work, a photonic physical unclonable function module, based on an optical waveguide, is demonstrated. The physical scrambling mechanism is based on the random and complex coherent interference of high order optical transverse modes. The proposed scheme allows the generation of random bit- strings, through a simple wavelength tuning of the laser source, that are suitable for a variety of cryptographic applications. The experimental data are evaluated in terms of unpredictability, employing typical information theory benchmark tests and the NIST statistical suit.

/pdf/random-number-generation-from-a-secure-photonic-physical-5674k1ca8z.pdf

Random Number Generation from a Secure Photonic Physical Unclonable Hardware Module

In an environment where cyber attacks are increasing, both in frequency and complexity, novel ways to shield data, users, and procedures have to be envisioned. Physical unclonable functions (PUFs) are the physical equivalent of one-way mathematical transformations with the exception that their inherent physical complexity renders them resilient to cloning. One interesting deployment scenario includes PUFs as random key generators. The deterministic nature of their operation alleviates the necessity to store the keys in non-volatile means. Along the same lines, blockchain is inherently resistant to modification of the data once stored while their overall security depends on the quality and secrecy of users’ keys. Here, the authors propose a novel optical PUF implementation that can be combined with private blockchain modalities in order to cyber-harden Internet of things ecosystems. PUF-related experimental results are presented, alongside implementation scenarios.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-sen.2018.5291

Optical PUFs as physical root of trust for blockchain-driven applications

In this paper we experimentally evaluate a physical unclonable function based on a polymer optical waveguide, as a time-invariant, replication-resilient, source of entropy. The elevated physical unclonability of our implementation is combined with spatial light modulation and post processing techniques, thus allowing the deterministic generation of an exponentially large pool of unpredictable responses. The quality of the generated numbers is validated through NIST/DIEHARD(ER) suites, whereas the overall security of the scheme is benchmarked assuming attackers with elevated privileges in terms of system access. Finally, based on the demonstrated key features, we present and analyze a mutual authentication implementation scenario which is fully compatible with state-of-the-art commercial Internet-Of-Things architectures

Charidimos Chaintoutis

Papers

Physical Unclonable Function based on a Multi-Mode Optical Waveguide.

Free Space Intra-Datacenter Interconnects Based on 2D Optical Beam Steering Enabled by Photonic Integrated Circuits

Random Number Generation from a Secure Photonic Physical Unclonable Hardware Module

Optical PUFs as physical root of trust for blockchain-driven applications

Photonic Pseudo-Random Number Generator for Internet-of-Things Authentication using a Waveguide based Physical Unclonable Function.