Physical layer security is a relatively new subfield inside security engineering and information theory that relies on properties of the wireless channel to secure or increase the security of the transmission. In this project we will develop a set of tools that will let us create a real world workbench for studying possible implementations about different physical layer security proposals. We will combine the powerful possibilities given by the open source project GNU Radio with the capacity of simulations and real software radio boards to understand the different experiments we can perform and the results that we should expect. At the very end, this projects aims to provide the necessary tools to bring real experiments related to physical layer security one step forward.
Physical layer security is a relatively new subfield inside security engineering and information theory that relies on properties of the wireless channel to secure or increase the security of the transmission. In this project we will develop a set of tools that will let us create a real world workbench for studying possible implementations about different physical layer security proposals. We will combine the powerful possibilities given by the open source project GNU Radio with the capacity of simulations and real software radio boards to understand the different experiments we can perform and the results that we should expect. At the very end, this projects aims to provide the necessary tools to bring real experiments related to physical layer security one step forward.
Security in wireless networks has traditionally been considered to be an issue to be addressed separately from the physical radio transmission aspects of wireless systems. However, with the emergence of new networking architectures that are not amenable to traditional methods of secure communication such as data encryption, there has been an increase in interest in the potential of the physical properties of the radio channel itself to provide communications security. Information theory provides a natural framework for the study of this issue, and there has been considerable recent research devoted to using this framework to develop a greater understanding of the fundamental ability of the so-called physical layer to provide security in wireless networks. Moreover, this approach is also suggestive in many cases of coding techniques that can approach fundamental limits in practice and of techniques for other security tasks such as authentication. This paper provides an overview of these developments.
Physical-layer security utilizes resources of the transmission medium to guarantee secure communication against an adversary with unlimited computational power. Rooted in information theory, physical-layer security advocates for a foundational approach by requiring security of communicated information as well as its reliability at the outset. The past decade has seen an unprecedented effort in physical-layer security research resulting in promising new design insights. The majority of these advances has been in wireless communications security, well-motivated by the fact that most data at large, including those of sensitive nature, flow over wireless links that are more vulnerable to security breaches, e.g., eavesdropping. At the same time, the open broadcast nature of wireless brings possibilities of cooperation by the network entities for improving security, e.g., resistance to eavesdropping. This article aims to provide an overview of research results in information-theoretic security with multiple wireless transmitters, and focuses on distilling insights for designing wireless systems with confidentiality guarantees.
Physical layer security (PHY-security) takes the advantages of channel randomness nature of transmission media to achieve communication confidentiality and authentication. Wiretap coding and signal processing technologies are expected to play vital roles in this new security mechanism. PHY-security has attracted a lot of attention due to its unique features and the fact that our daily life relies heavily on wireless communications for sensitive and private information transmissions. Compared to conventional cryptography that works to ensure all involved entities to load proper and authenticated cryptographic information, PHY-security technologies perform security functions without considering about how those security protocols are executed. In other words, it does not require to implement any extra security schemes or algorithms on other layers above the physical layer. This survey introduces the fundamental theories of PHY-security, covering confidentiality and authentication, and provides an overview on the state-of-the-art works on PHY-security technologies that can provide secure communications in wireless systems, along with the discussions on challenges and their proposed solutions. Furthermore, at the end of this paper, the open issues are identified as our future research directions.
Wireless communications are naturally exposed to important security risks due to their broadcast nature. In contrast with wired communications, no physical medium is isolating the transmission surroundings to a specific path. Traditional methods to reach the goals of communications security rely on algorithms at protocol stack level, which are based on mathematically derived cryptographic protocols. With the tremendous proliferation of wireless devices, and the increase in computational power available for decryption, traditional cryptographic measures may be compromised. To protect communications at the lowest level, physical layer (PHY) security methods have been proposed recently. These techniques aim to ensure secure communications by exploiting the unique characteristics of the physical medium between communicating nodes, effectively reducing the decryption capabilities of an eavesdropper to intercept transmissions. This thesis explains within a general framework the most important PHY layer security schemes. First we explore approaches which utilize the knowledge of the unique channel between communicating nodes to distort a transmitted signal with various kinds of randomizations, in such a way that the intended receivers are unaffected by the distortion, but any other observer will be exposed to it. These techniques, however, introduce several trade-offs between transmission resources and the effectiveness in achieving secrecy. Of particular interest for this investigation is a class of methods which can be referred to as "security enhancing techniques", in which minimal priors about the potential eavesdroppers locations and capabilities are assumed. In this thesis, a wave-based approach to the communication secrecy problem is introduced. An interesting perspective is provided by studying the relation between electromagnetic theory and information theory, the so-called electromagnetic information theory. This allows to properly identify the unavoidable limitations imposed by the laws of electromagnetics to our ability to communicate securely. The proposed model can be extended to the analysis of different signal distortion methodologies and different channel conditions. The resulting approach is highly relevant to the study of PHY layer security methods since it is physically fundamental as well as architecture independent, which leads to a consolidating point of view of the secrecy problem. In addition, the thesis presents computer simulation results which shed insight on the security possibilities and limitations of three different security scenarios, which are termed MISO (multiple-input, single-output) (with single eavesdropper), MISOME (multiple-input, single-output, multiple eavesdropper), and MIMOME (multiple-input, multiple-output, multiple-eavesdropper).
Securing wireless communication against eavesdropping is critical, particularly in dynamic and decentralized environments. We present gr-PHYSEC, a new GNU Radio out-of-tree (OOT) module for real-time physical-layer key generation. Unlike traditional key generation that relies on pre-shared secrets or computational complexity, our approach derives symmetric keys from the wireless channel's inherent randomness. We embed a trained neural network within GNU Radio to extract channel features between trusted parties (Alice and Bob) during probe exchanges. These features are quantized into binary keys, reconciled via Reed-Solomon encoding, and further secured with SHA-512 hashing. The generated keys are then directly used to encrypt data. Real-world experiments at the FAU CAAI connected robotics testbed using ADALM Pluto software-defined radios and NVIDIA Jetson Orin validate the approach with ground robotic platforms. Results demonstrate low key disagreement rates and strong randomness, as verified by the NIST test suite for random and pseudorandom number generators for cryptographic applications. This integration showcases how GNU Radio can support real-time AI-driven security solutions, pushing the boundaries of software-defined secure communication. The source code for this project is available at: https://github.com/C2A2-at-Florida-Atlantic-University/gr-PHYSEC
The wireless channel is inherently an open medium which exposes wireless communication users to the risk of interception. The vulnerabilities of the wireless channel have led to the search for innovative and efficient security solutions at different levels of the network protocol. In particular, the physical layer level allows for implementing some security functions, such as key generation and exchange, by exploiting the intrinsic randomness of the wireless communication channel. In this paper, we analyze the effect of wireless channel and of antenna characteristics on physical layer security (PLS) key generation. The aim is to put in evidence the relation between physical quantities, such as radio channel characteristics or antenna directivity, with higher level secrecy performance indicators, such as the key mismatch between the different communication nodes and the key randomness. For this purpose, we developed a comprehensive numerical model, which implements all the different steps, from signal generation and wireless propagation modeling to key generation through spectral quantization. The reported results show that the multipath richness of the radio channel, as in outdoor urban scenarios, improves the PLS secrecy performances with respect to simpler propagation scenarios. Moreover, we show that the use of more directive antennas in the legitimate communication link improves secrecy. An opposite effect is achieved when the directivity of the eavesdropper antenna is increased, thus improving its ability to perform passive attacks.