Biblio

Physical Unclonable Functions (PUFs) are a promising technology to secure low-cost devices. A PUF is a function whose values depend on the physical characteristics of the underlying hardware: the same PUF implemented on two identical integrated circuits will return different values. Thus, a PUF can be used as a unique fingerprint identifying one specific physical device among (apparently) identical copies that run the same firmware on the same hardware. PUFs, however, are tricky to implement, and a number of attacks have been reported in the literature, often due to wrong assumptions about the provided security guarantees and/or the attacker model. In this paper, we present the first mechanized symbolic model for PUFs that allows for precisely reasoning about their security with respect to a variegate set of attackers. We consider mutual authentication protocols based on different kinds of PUFs and model attackers that are able to access PUF values stored on servers, abuse the PUF APIs, model the PUF behavior and exploit error correction data to reproduce the PUF values. We prove security properties and we formally specify the capabilities required by the attacker to break them. Our analysis points out various subtleties, and allows for a systematic comparison between different PUF-based protocols. The mechanized models are easily extensible and can be automatically checked with the Tamarin prover.

Cyber-physical systems (CPS) and their Internet of Things (IoT) components are repeatedly subject to various attacks targeting weaknesses in their firmware. For that reason emerges an imminent demand for secure update mechanisms that not only include specific systems but cover all parts of the critical infrastructure. In this paper we introduce a theoretical concept for a secure CPS device update and verification mechanism and provide information on handling hardware-based security incorporating trusted platform modules (TPM) on those CPS devices. We will describe secure communication channels by state of the art technology and also integrity measurement mechanisms to ensure the system is in a known state. In addition, a multi-level fail-over concept is presented, ensuring continuous patching to minimize the necessity of restarting those systems.

Multimedia authentication is an integral part of multimedia signal processing in many real-time and security sensitive applications, such as video surveillance. In such applications, a full-fledged video digital rights management (DRM) mechanism is not applicable due to the real time requirement and the difficulties in incorporating complicated license/key management strategies. This paper investigates the potential of multimedia authentication from a brand new angle by employing hardware-based security primitives, such as physical unclonable functions (PUFs). We show that the hardware security approach is not only capable of accomplishing the authentication for both the hardware device and the multimedia stream but, more importantly, introduce minimum performance, resource, and power overhead. We justify our approach using a prototype PUF implementation on Xilinx FPGA boards. Our experimental results on the real hardware demonstrate the high security and low overhead in multimedia authentication obtained by using hardware security approaches.