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.

Abstract. 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 bitstrings, 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.

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.Photonics 2018, 5, 21 2 of 10 traffic increases. New architectures (e.g., based on modular designs) have been recently proposed addressing these issues [4]. However, the proposed solutions impose other challenges that demand low-cost/low-power dynamic re-configurability and seamless scalability [5].Optical fibers and fiber-pigtailed transceivers are the key elements in constructing traditional DCNs. Millions of meters of fiber are required, forming an extremely complex cabling system that is difficult to manage [6], with the choice of cabling architecture greatly influencing the throughput, scalability, and energy efficiency management of a DC [6,7]. Although the cabling problem is still underestimated, when the scaling and cost of large infrastructures is under consideration, recent studies have started paying attention to its side effects. For instance, it was shown that the mass of long cables between the switches causes great difficulties in system maintenance [5]. When the network connection changes or line failure occurs, the system upgrading becomes extremely complicated. IBM also reported that the dense cabling will affect the heat dissipation due to the fact that airflow is obstructed [8], while HP reported that mapping a logical topology with servers, switches, and links onto a physical space with racks and cable trays such that the cable costs are minimized is a non-deterministic polynomial-time hard (NP-hard) problem [9].At the same time, the traditional way of designing DCNs, through the use of electrical packet switches in a multitier topology, has a fundamental weakness, namely that it has to be decided in advance whether to provide overprovisioned or oversubscribed interconnects between top of rack ...

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.