Biblio

This paper assesses the impact on the performance that information-theoretic physical layer security (IT-PLS) introduces when integrated into a 5G New Radio (NR) system. For this, we implement a wiretap code for IT-PLS based on a modular coding scheme that uses a universal-hash function in its security layer. The main advantage of this approach lies in its flexible integration into the lower layers of the 5G NR protocol stack without affecting the communication's reliability. Specifically, we use IT-PLS to secure the transmission of downlink control information by integrating an extra pre-coding security layer as part of the physical downlink control channel (PDCCH) procedures, thus not requiring any change of the 3GPP 38 series standard. We conduct experiments using a real-time open-source 5G NR standalone implementation and use software-defined radios for over-the-air transmissions in a controlled laboratory environment. The overhead added by IT-PLS is determined in terms of the latency introduced into the system, which is measured at the physical layer for an end-to-end (E2E) connection between the gNB and the user equipment.

The high maneuverability of the unmanned aerial vehicle (UAV), facilitating fast and flexible deployment of communication infrastructures, brings potentially valuable opportunities to the future wireless communication industry. Nevertheless, UAV communication networks are faced with severe security challenges since air to ground (A2G) communications are more vulnerable to eavesdropping attacks than terrestrial communications. To solve the problem, we propose a coding scheme that hierarchically utilizes polar codes in order to address channel multi-state variation for UAV wiretap channels, without the instantaneous channel state information (CSI) known at the transmitter. The theoretical analysis and simulation results show that the scheme achieves the security capacity of the channel and meets the conditions of reliability and security.

In this paper we use a seeded modular coding scheme for implementing physical layer security in a wiretap scenario. This modular scheme consists of a traditional coding layer and a security layer. For the traditional coding layer, we use a polar code. We evaluate the performance of the seeded modular coding scheme in an experimental setup with software defined radios and compare these results to simulation results. In order to assess the secrecy level of the scheme, we employ the distinguishing security metric. In our experiments, we compare the distinguishing error rate for different seeds and block lengths.

Physical-layer security is a new paradigm that offers data protection against eavesdropping in wireless 5G networks. In this context, the Gaussian channel is a typical model that captures the practical aspects of confidentially transmitting a message through the wireless medium. In this paper, we consider the peculiar case of transmitting a message through a wireless, state-dependent channel which is prone to eavesdropping, where the state knowledge is non-causally known and shared between the sender and the eavesdropper. We show that a novel structured coding scheme, which combines random coding arguments and the dirty-paper coding technique, achieves the fundamental limit of secure and reliable communication for the considered model.

Information leakage estimation for practical wiretap codes is a challenging task for which existing solutions are either too complex or suboptimal, and don't scale for large blocklengths. In this paper we present a new method, based on a modified version of the successive cancellation decoder in order to compute the information leakage for the wiretap polar code which improves upon existing methods in terms of complexity and accuracy. Results are presented for classical binary-input symmetric channels alike the Binary Erasure Channel (BEC), the Binary Symmetric Channel (BSC) and Binary Input Additive White Gaussian Noise channel (BI-AWGN).

With the explosive development of big data, it is necessary to sort the data according to their importance or priorities. The sources with different importance levels can be modeled by the multilevel diversity coding systems (MDCS). Another trend in future communication networks, say 5G wireless networks and Internet of Things, is that users may obtain their data from all available sources, even from devices belonging to other users. Then, the privacy of data becomes a crucial issue. In a recent work by Li et al., the secure asymmetric MDCS (S-AMDCS) with wiretap channels was investigated, where the wiretapped messages do not leak any information about the sources (i.e. perfect secrecy). It was shown that superposition (source-separate coding) is not optimal for the general S-AMDCS and the exact full secure rate region was proved for a class of S-AMDCS. In addition, a bound on the key size of the secure rate region was provided as well. As a further step on the SAMDCS problem, this paper mainly focuses on the key size characterization. Specifically, the constraints on the key size of superposition secure rate region are proved and a counterexample is found to show that the bound on the key size of the exact secure rate region provided by Li et al. is not tight. In contrast, tight necessary and sufficient constraints on the secrecy key size of the counterexample, which is the four-encoder S-AMDCS, are proved.

In practical wireless communication systems, the channel conditions of legitimate users can not always be better than those of eavesdroppers. This realistic fact brings the challenge for the design of secure transmission over wiretap channels which requires that the eavesdropping channel conditions should be worse than legitimate channels. In this paper, we present a robust chaos-based information masking polar coding scheme for enhancing reliability and security performances under realistic channel conditions for practical systems. In our design, we mask the original information, wherein the masking matrix is determined by chaotic sequences. Then the masked information is encoded by the secure polar coding scheme. After the channel polarization achieved by the polar coding, we could identify the bit-channels providing good transmission conditions for legitimate users and the bit-channels with bad conditions for eavesdroppers. Simulations are performed over the additive white Gaussian noise (AWGN) and slow flat-fading Rayleigh channels. The results demonstrate that compared with existing schemes, the proposed scheme can achieve better reliability and security even when the eavesdroppers have better channel conditions than legitimate users, hence the practicability is greatly enhanced.

This paper presents the recent progress in studying the algorithmic computability of capacity expressions of secure communication systems. Several communication scenarios are discussed and reviewed including the classical wiretap channel, the wiretap channel with an active jammer, and the problem of secret key generation.

In this paper, we propose a frozen bit selection scheme for polar coding scheme combined with physical layer security that enhances the security of two legitimate users on a wiretap channel. By flipping certain frozen bits, the bit-error rate (BER) of an eavesdropper is maximized while the BER of the legitimate receiver is unaffected. An ARQ protocol is proposed that only feeds back a small proportion of the frozen bits to the transmitter, which increases the secrecy rate. The scheme is evaluated on a wiretap channel affected by impulsive noise and we consider cases where the eavesdropper's channel is actually more impulsive than the main channel. Simulation results show that the proposed scheme ensures the eavesdropper's BER is high even when only one frozen bit is flipped and this is achieved even when their channel is more impulsive than the main channel.

Post-quantum secure communication has attracted much interest in recent years. Known computationally secure post-quantum key agreement protocols are resource intensive for small devices. These devices may need to securely send frequent short messages, for example to report the measurement of a sensor. Secure communication using physical assumptions provides information-theoretic security (and so quantum-safe) with small computational over-head. Security and efficiency analysis of these systems however is asymptotic. In this poster we consider two secure message communication systems, and derive and compare their security and efficiency for finite length messages. Our results show that these systems indeed provide an attractive alternative for post-quantum security.

Next generation 5G wireless networks pose several important security challenges. One fundamental challenge is key management between the two communicating parties. The goal is to establish a common secret key through an unsecured wireless medium. In this paper, we introduce a new physical layer paradigm for secure key exchange between the legitimate communication parties in the presence of a passive eavesdropper. The proposed method ensures secrecy via pre-equalization and guarantees reliable communications by the use of Low Density Parity Check (LDPC) codes. One of the main findings of this paper is to demonstrate through simulations that the diversity order of the eavesdropper will be zero unless the main and eavesdropping channels are almost correlated, while the probability of key mismatch between the legitimate transmitter and receiver will be low. Simulation results demonstrate that the proposed approach achieves very low secret key mismatch between the legitimate users, while ensuring very high error probability at the eavesdropper.