Optical key distribution concept assessment for secure communication in space (artes 4.0 sl spl 3a.231) expro+ (on request)

Objective: The objective of this activity is to develop and test a free-space communication link with optical key distribution (OKD) functionality.TargetedImprovements:Improvement of the key distribution rate by at least a factor of 100 with respect to QKD, alternatively, the reduction of the aperture sizes of both terminals(for the same key rate as QKD). Provision of the security assessment for OKD.Description: In the vast majority of cases, the security of communication systems is only ensured at their digital layers, leaving the lowest physical layer open toeavesdropping and interference. The primary concern in space scenarios is passive attacks, where the adversary is often able to capture an even largerportion of the signal than the legitimate receiver(s). At the same time, feasible physical layer security (PLS) solutions must meet the stringent SWaP (size,weight, and power) requirements of space missions and should be easily integrated with data transmission, even in the case of the simplest intensitymodulation/direct detection (IM/DD) links.Optical Key Distribution (OKD) is a promising solution for secure communication. It allows authenticated parties to establish a secure cryptographic key,by exploiting the high directionality of optical beams. By using optical noise, OKD is cost-effective and suitable for free-space communications, such asinter-satellite and satellite-to-ground links. The technique distributes a secure key that can be used for encryption protocols like AES, SSL/TLS, or as aone-time pad. It avoids the complexities and high costs of quantum key distribution (QKD) systems while providing adequate security for free-spacescenarios. OKD keys are quantum-safe, assuming the adversary's detection capability is limited by shot noise.The activity aims to investigate and develop a cost-effective solution for the physical layer security of optical satellite communication links, namely OpticalKey Distribution (OKD), which allows authenticated parties to establish a secure key, by monitoring the presence of an eavesdropper along the satellite to-ground line-of-sight, while avoiding the complexity and resulting significant costs of Quantum Key Distribution (QKD) systems. The activity will establishsecurity assumption for OKD and provide the security assessment of the proposed OKD system. The outcome of this work shall be evaluated by a security expert with competencies in the protection of communication links.