1,038 research outputs found
Analysis of Channel-Based User Authentication by Key-Less and Key-Based Approaches
User authentication (UA) supports the receiver in deciding whether a message
comes from the claimed transmitter or from an impersonating attacker. In
cryptographic approaches messages are signed with either an asymmetric or
symmetric key, and a source of randomness is required to generate the key. In
physical layer authentication (PLA) instead the receiver checks if received
messages presumably coming from the same source undergo the same channel. We
compare these solutions by considering the physical-layer channel features as
randomness source for generating the key, thus allowing an immediate comparison
with PLA (that already uses these features). For the symmetric-key approach we
use secret key agreement, while for asymmetric-key the channel is used as
entropy source at the transmitter. We focus on the asymptotic case of an
infinite number of independent and identically distributed channel
realizations, showing the correctness of all schemes and analyzing the secure
authentication rate, that dictates the rate at which the probability that UA
security is broken goes to zero as the number of used channel resources (to
generate the key or for PLA) goes to infinity. Both passive and active attacks
are considered and by numerical results we compare the various systems
Secure OFDM System Design for Wireless Communications
Wireless communications is widely employed in modern society and plays an increasingly important role in people\u27s daily life. The broadcast nature of radio propagation, however, causes wireless communications particularly vulnerable to malicious attacks, and leads to critical challenges in securing the wireless transmission. Motivated by the insufficiency of traditional approaches to secure wireless communications, physical layer security that is emerging as a complement to the traditional upper-layer security mechanisms is investigated in this dissertation. Five novel techniques toward the physical layer security of wireless communications are proposed. The first two techniques focus on the security risk assessment in wireless networks to enable a situation-awareness based transmission protection. The third and fourth techniques utilize wireless medium characteristics to enhance the built-in security of wireless communication systems, so as to prevent passive eavesdropping. The last technique provides an embedded confidential signaling link for secure transmitter-receiver interaction in OFDM systems
Physical layer security for massive MIMO: An overview on passive eavesdropping and active attacks
This article discusses opportunities and challenges of physical layer security integration in MaMIMO systems. Specifically, we first show that MaMIMO itself is robust against passive eavesdropping attacks. We then review a pilot contamination scheme that actively attacks the channel estimation process. This pilot contamination attack not only dramatically reduces the achievable secrecy capacity but is also difficult to detect. We proceed by reviewing some methods from literature that detect active attacks on MaMIMO. The last part of the article surveys the open research problems that we believe are the most important to address in the future and give a few promising directions of research to solve them
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