PROPHYLAXE

Security has become a predominant critical application requirement in wireless communication systems: it is e.g. a key issue in the envisioned IoT which involves machine-type communication of many, many battery driven nodes with low-complex wireless transceivers. Applications range from (but are not limited to) telemedicine, facility management, smart home networks etc. Secure solutions for such applications are mandatory not only because of sensitive personal information but also due to data integrity requirements etc.

It is common understanding that the required security level is established as part of the application layer. However, current security solutions for IoT fall far short due to the scalability problem: Nodes must be flexible managed and distributed in the network. Asymmetric schemes used on application layer (e.g. in web browsers) are too complex as well as computational- and energy intensive. Symmetric key schemes are 100 ... 1000 times less complex (“lightweight security”) but assume a common secret key for the nodes. The key to solve the scalability problem within the PROPHYLAXE project is Physical Layer Security.

Physical Layer Security is a promising new approach to establish security in the IoT: It uses the principle of “physically unclonable function”, such as the wireless channel, to establish a unique secret key between the communication partners which is impossible to intercept. It makes use of information-theoretic results which can even guarantee “perfect secrecy”. Since keys are automatically installed, key distribution in these systems is easy to manage and requires no user interaction. A further side effect is its invulnerability against attacks on physical layer control signaling which is typically exchanged without further protection opening trap doors for possible misuse. Even though basic protection is provided security threats are still possible by code cracks or other rather ordinary incidents such as identity theft etc.

PROPHYLAXE exploits physical layer security mechanisms by means of inherent wireless system properties based on the fading nature of wireless channels. Although traditionally seen as a burden the fading nature provides two mechanisms that can be exploited: 1) the channel variations are reliably observable only by the legitimate receiver and 2) the transmitter can adapt to the channel conditions and control resources in a beneficial way. PROPHYLAXE aims to exploit these features and establishes security architecture for the IoT including design of physical layer protocols for advanced security in a heterogeneous or even hostile environment. Information-theoretic performance limits will outline the level of security dependent on the complexity of protocols and signal processing.