Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1805.06182

Covert Wireless Communications with Active Eavesdropper on AWGN Channels

Zhihong Liu, Jiajia Liu, Yong Zeng, Jianfeng Ma, Qiping Huang

Published May 16, 2018• 2 citations
arXivHTMLPDF

Abstract

Covert wireless communication can prevent an adversary from knowing the existence of user's transmission, thus provide stronger security protection. In AWGN channels, a square root law was obtained and the result shows that Alice can reliably and covertly transmit $\mathcal{O}(\sqrt{n})$ bits to Bob in n channel uses in the presence of a passive eavesdropper (Willie). However, existing work presupposes that Willie is static and only samples the channels at a fixed place. If Willie can dynamically adjust the testing distance between him and Alice according to his sampling values, his detection probability of error can be reduced significantly via a trend test. We found that, if Alice has no prior knowledge about Willie, she cannot hide her transmission behavior in the presence of an active Willie, and the square root law does not hold in this situation. We then proposed a novel countermeasure to deal with the active Willie. Through randomized transmission scheduling, Willie cannot detect Alice's transmission attempts if Alice can set her transmission probability below a threshold. Additionally, we systematically evaluated the security properties of covert communications in a dense wireless network, and proposed a density-based routing scheme to deal with multi-hop covert communication in a wireless network. As the network grows denser, Willie's uncertainty increases, and finally resulting in a "shadow" network to Willie.

DOI
10.48550/arxiv.1805.06182

Related papers

Hiding Communications in AWGN Channels and THz Band with Interference Uncertainty

Zhihong Liu, Jiajia Liu, Yong Zeng +1 more

Covert communication can prevent an adversary from knowing that a wireless transmission has occurred. In additive white Gaussian noise (AWGN) channels, a square root law is found that Alice can reliably and covertly transmit $\mathcal{O}(\sqrt{n})$ bits to Bob in $n$ channel uses. In this paper, we consider covert communications in noisy wireless networks, where the receivers not only experience the background noise, but also the aggregate interference from other transmitters. Our results show that uncertainty in interference experienced by the adversary Willie is beneficial to Alice. In AWGN channels, when the distance between Alice and Willie $d_{a,w}=ω(n^{1/(2α)})$ ($α$ is the path loss exponent), Alice can reliably and covertly transmit $\mathcal{O}(\log_2\sqrt{n})$ bits to Bob in $n$ channel uses. Although the covert throughput is lower than the square root law, the spatial throughput is higher. In THz (Terahertz) Band networks,covert communication is more difficult because Willie can simply place a receiver in the narrow beam between Alice and Bob to detect or block their LOS (Line-of-Sight) communications. We then present a covert communication scheme that utilizes the reflection or diffuse scattering from a rough surface to prevent being detected by Willie. From the network perspective, the communications are hidden in the interference of noisy wireless networks, and what Willie sees is merely a "shadow" wireless network.

arXiv:1909.12752•Sep 26, 2019•0 citations

Covert Wireless Communications in IoT Systems: Hiding Information in Interference

Zhihong Liu, Jiajia Liu, Yong Zeng +1 more

Wireless channels are increasingly being used to transmit highly sensitive information in the Internet of Things. However, traditional cryptography methods cannot solve all security problems in IoT systems. Covert wireless communication can prevent an adversary from knowing the existence of a user's transmission; thus, it can provide stronger security protection for IoT devices. In this article, we consider the covert communication in a noisy wireless network, and find that the uncertainty of the aggregated interference experienced by the adversary is beneficial to the potential transmitters. From the network perspective, wireless communications can be hidden in the interference of the noisy wireless network, which the adversary observes as a "shadow" network to a certain extent. Furthermore, we discuss some new results on the effect of active eavesdropper. Square root law becomes invalid, and even jammer-assisted schemes have little effect on the covertness in the presence of active eavesdropper. Finally, we provide a vision for future research.

IEEE Wireless Communications•Dec 1, 2018•93 citations

The Sound and the Fury: Hiding Communications in Noisy Wireless Networks with Interference Uncertainty

Zhihong Liu, Jiajia Liu, Yong Zeng +2 more

Covert communication can prevent the adversary from knowing that a wireless transmission has occurred. In the additive white Gaussian noise channels, a square root law is obtained and the result shows that Alice can reliably and covertly transmit $\mathcal{O}(\sqrt{n})$ bits to Bob in $n$ channel uses. If additional "friendly" node near the adversary can inject artificial noise to aid Alice in hiding her transmission attempt, covert throughput can be improved, i.e., Alice can covertly transmit $\mathcal{O}(\min\{n,λ^{α/2}\sqrt{n}\})$ bits to Bob over $n$ uses of the channel ($λ$ is the density of friendly nodes and $α$ is the path loss exponent of wireless channels). In this paper, we consider the covert communication in a noisy wireless network, where Bob and the adversary Willie not only experience the background noise, but also the aggregated interference from other transmitters. Our results show that uncertainty in interference experienced by Willie is beneficial to Alice. When the distance between Alice and Willie $d_{a,w}=ω(n^{δ/4})$ ($δ=2/α$ is stability exponent), Alice can reliably and covertly transmit $\mathcal{O}(\log_2\sqrt{n})$ bits to Bob in $n$ channel uses. Although the covert throughput is lower than the square root law and the friendly jamming scheme, the spatial throughput is higher. From the network perspective, the communications are hidden in "the sound and the fury" of noisy wireless networks, and what Willie sees is merely a "shadow" wireless network. He knows for certain that some nodes are transmitting, but he cannot catch anyone red-handed.

arXiv:1712.05099•Dec 14, 2017•5 citations

Covert Communication With the Help of Relay and Channel Uncertainty

Jianquan Wang, Wanbin Tang, Qiangqiang Zhu +3 more

Covert communication aims to hide the existence of the transmissions to guarantee the security in wireless communications. In this letter, channel uncertainty is exploited to achieve covert communication in relay networks. The transmitter Alice sends messages to the legitimate receiver Bob with the help of a relay, while the warden Willie wants to detect the existence of the transmission. The channel uncertainty introduces confusions to degrade the performance of Willie's detection. We show that Alice can transmit ${O}$ (${n}$ ) bits in ${n}$ channel uses covertly with the help of relay and channel uncertainty. Numerical results are shown to illustrate the achievability and the performance of the considered scenario.

IEEE Wireless Communications Letters•Sep 24, 2018•183 citations

Covert Wireless Communication in IoT Network: From AWGN Channel to THz Band

Zhihong Liu, Jiajia Liu, Yong Zeng +1 more

Covert communication can prevent an adversary from knowing that a transmission has occurred between two users. In this article, we consider covert wireless communications in an Internet-of-Things (IoT) network with dense deployment, where an IoT device experiences not only the background noise but also the aggregates interference from other Tx devices. Our results show that in a dense IoT network with lower frequency AWGN channels, when the distance between Alice and the adversary Willie da,w= ω(n1/(2α)), Alice can reliably and covertly transmit O(log2√n) bits to Bob in n channel uses. In an IoT network with terahertz (THz) band, covert communication is more difficult because Willie can simply place a receiver in the narrow beam between Alice and Bob in order to detect or block their line-of-sight communications. We demonstrated that covert communication is still possible in this occasion by utilizing the reflection or diffuse scattering from a rough surface. From the physical-layer security perspective, covert communication can enhance the security of IoT network from the bottom layer.

IEEE Internet of Things Journal•Jan 21, 2020•74 citations

Covert Communication Gains From Adversary’s Ignorance of Transmission Time

Boulat A. Bash, Dennis Goeckel, Don Towsley

The recent square root law (SRL) for covert communication demonstrates that Alice can reliably transmit O(√n) bits to Bob in n uses of an additive white Gaussian noise (AWGN) channel while keeping ineffective any detector employed by the adversary; conversely, exceeding this limit either results in detection by the adversary with high probability or nonzero decoding error probability at Bob. This SRL is under the assumption that the adversary knows when Alice transmits (if she transmits); however, in many operational scenarios, he does not know this. Hence, here, we study the impact of the adversary's ignorance of the time of the communication attempt. We employ a slotted AWGN channel model with T(n) slots each containing n symbol periods, where Alice may use a single slot out of T(n). Provided that Alice's slot selection is secret, the adversary needs to monitor all T(n) slots for possible transmission. We show that this allows Alice to reliably transmit O(min{(n log T(n))1/2, n}) bits to Bob (but no more) while keeping the adversary's detector ineffective. To achieve this gain over SRL, Bob does not have to know the time of transmission provided T(n)cTn, cT= O(1).

arXiv:1403.1013•IEEE Transactions on Wireless Communications•Sep 29, 2016•152 citations
Covert wireless communication can prevent an adversary from knowing the existence of user's transmission, thus provide stronger security protection. In AWGN channels, a square root law was obtained and the result shows that Alice can reliably and covertly transmit O(n)\mathcal{O}(\sqrt{n})O(n​) bits to Bob in n channel uses in the presence of a passive eavesdropper (Willie). However, existing work presupposes that Willie is static and only samples the channels at a fixed place. If Willie can dynamically adjust the testing distance between him and Alice according to his sampling values, his detection probability of error can be reduced significantly via a trend test. We found that, if Alice has no prior knowledge about Willie, she cannot hide her transmission behavior in the presence of an active Willie, and the square root law does not hold in this situation. We then proposed a novel countermeasure to deal with the active Willie. Through randomized transmission scheduling, Willie cannot detect Alice's transmission attempts if Alice can set her transmission probability below a threshold. Additionally, we systematically evaluated the security properties of covert communications in a dense wireless network, and proposed a density-based routing scheme to deal with multi-hop covert communication in a wireless network. As the network grows denser, Willie's uncertainty increases, and finally resulting in a "shadow" network to Willie.
Covert communication can prevent an adversary from knowing that a wireless transmission has occurred. In additive white Gaussian noise (AWGN) channels, a square root law is found that Alice can reliably and covertly transmit O(n)\mathcal{O}(\sqrt{n})O(n​) bits to Bob in nnn channel uses. In this paper, we consider covert communications in noisy wireless networks, where the receivers not only experience the background noise, but also the aggregate interference from other transmitters. Our results show that uncertainty in interference experienced by the adversary Willie is beneficial to Alice. In AWGN channels, when the distance between Alice and Willie da,w=ω(n1/(2α))d_{a,w}=ω(n^{1/(2α)})da,w​=ω(n1/(2α)) (ααα is the path loss exponent), Alice can reliably and covertly transmit O(log⁡2n)\mathcal{O}(\log_2\sqrt{n})O(log2​n​) bits to Bob in nnn channel uses. Although the covert throughput is lower than the square root law, the spatial throughput is higher. In THz (Terahertz) Band networks,covert communication is more difficult because Willie can simply place a receiver in the narrow beam between Alice and Bob to detect or block their LOS (Line-of-Sight) communications. We then present a covert communication scheme that utilizes the reflection or diffuse scattering from a rough surface to prevent being detected by Willie. From the network perspective, the communications are hidden in the interference of noisy wireless networks, and what Willie sees is merely a "shadow" wireless network.
Wireless channels are increasingly being used to transmit highly sensitive information in the Internet of Things. However, traditional cryptography methods cannot solve all security problems in IoT systems. Covert wireless communication can prevent an adversary from knowing the existence of a user's transmission; thus, it can provide stronger security protection for IoT devices. In this article, we consider the covert communication in a noisy wireless network, and find that the uncertainty of the aggregated interference experienced by the adversary is beneficial to the potential transmitters. From the network perspective, wireless communications can be hidden in the interference of the noisy wireless network, which the adversary observes as a "shadow" network to a certain extent. Furthermore, we discuss some new results on the effect of active eavesdropper. Square root law becomes invalid, and even jammer-assisted schemes have little effect on the covertness in the presence of active eavesdropper. Finally, we provide a vision for future research.
Covert communication can prevent the adversary from knowing that a wireless transmission has occurred. In the additive white Gaussian noise channels, a square root law is obtained and the result shows that Alice can reliably and covertly transmit O(n)\mathcal{O}(\sqrt{n})O(n​) bits to Bob in nnn channel uses. If additional "friendly" node near the adversary can inject artificial noise to aid Alice in hiding her transmission attempt, covert throughput can be improved, i.e., Alice can covertly transmit O(min⁡{n,λα/2n})\mathcal{O}(\min\{n,λ^{α/2}\sqrt{n}\})O(min{n,λα/2n​}) bits to Bob over nnn uses of the channel (λλλ is the density of friendly nodes and ααα is the path loss exponent of wireless channels). In this paper, we consider the covert communication in a noisy wireless network, where Bob and the adversary Willie not only experience the background noise, but also the aggregated interference from other transmitters. Our results show that uncertainty in interference experienced by Willie is beneficial to Alice. When the distance between Alice and Willie da,w=ω(nδ/4)d_{a,w}=ω(n^{δ/4})da,w​=ω(nδ/4) (δ=2/αδ=2/αδ=2/α is stability exponent), Alice can reliably and covertly transmit O(log⁡2n)\mathcal{O}(\log_2\sqrt{n})O(log2​n​) bits to Bob in nnn channel uses. Although the covert throughput is lower than the square root law and the friendly jamming scheme, the spatial throughput is higher. From the network perspective, the communications are hidden in "the sound and the fury" of noisy wireless networks, and what Willie sees is merely a "shadow" wireless network. He knows for certain that some nodes are transmitting, but he cannot catch anyone red-handed.
Covert communication aims to hide the existence of the transmissions to guarantee the security in wireless communications. In this letter, channel uncertainty is exploited to achieve covert communication in relay networks. The transmitter Alice sends messages to the legitimate receiver Bob with the help of a relay, while the warden Willie wants to detect the existence of the transmission. The channel uncertainty introduces confusions to degrade the performance of Willie's detection. We show that Alice can transmit O{O}O (n{n}n ) bits in n{n}n channel uses covertly with the help of relay and channel uncertainty. Numerical results are shown to illustrate the achievability and the performance of the considered scenario.
Covert communication can prevent an adversary from knowing that a transmission has occurred between two users. In this article, we consider covert wireless communications in an Internet-of-Things (IoT) network with dense deployment, where an IoT device experiences not only the background noise but also the aggregates interference from other Tx devices. Our results show that in a dense IoT network with lower frequency AWGN channels, when the distance between Alice and the adversary Willie da,w= ω(n1/(2α)), Alice can reliably and covertly transmit O(log2√n) bits to Bob in n channel uses. In an IoT network with terahertz (THz) band, covert communication is more difficult because Willie can simply place a receiver in the narrow beam between Alice and Bob in order to detect or block their line-of-sight communications. We demonstrated that covert communication is still possible in this occasion by utilizing the reflection or diffuse scattering from a rough surface. From the physical-layer security perspective, covert communication can enhance the security of IoT network from the bottom layer.
The recent square root law (SRL) for covert communication demonstrates that Alice can reliably transmit O(√n) bits to Bob in n uses of an additive white Gaussian noise (AWGN) channel while keeping ineffective any detector employed by the adversary; conversely, exceeding this limit either results in detection by the adversary with high probability or nonzero decoding error probability at Bob. This SRL is under the assumption that the adversary knows when Alice transmits (if she transmits); however, in many operational scenarios, he does not know this. Hence, here, we study the impact of the adversary's ignorance of the time of the communication attempt. We employ a slotted AWGN channel model with T(n) slots each containing n symbol periods, where Alice may use a single slot out of T(n). Provided that Alice's slot selection is secret, the adversary needs to monitor all T(n) slots for possible transmission. We show that this allows Alice to reliably transmit O(min{(n log T(n))1/2, n}) bits to Bob (but no more) while keeping the adversary's detector ineffective. To achieve this gain over SRL, Bob does not have to know the time of transmission provided T(n)cTn, cT= O(1).