Secure transmission with different security requirements based on covert communication and information-theoretic security in the presence of friendly jammer
Abstract This paper addresses the power allocation problem in a network where joint information-theoretic secrecy and covert communication are required. In this network, a single transmitter (Alice) sends information to two legitimate users (Bob and Carol). There is also an untrusted user who attempts to detect the content of Bob’s message and a warden (Willie) who wants to detect the existence of communication between Alice and the two users. Thus, Carol requires covert transmission, and Bob requires secure and covert communication. The network utilizes a friendly jammer to address these demands and overcome the low transmission rate of covert communication. To achieve covert communication, Alice sends both users’ data simultaneously in selected time slots to hide it from Willie, while the jammer continuously transmits signals in all time slots. The objective is to maximize the average transmission rate over the allocated powers of Bob, Carol, and the jammer while meeting the two users’ requirements. A novel iterative algorithm is proposed to obtain an effective solution. Simulation results indicate that the proposed method can enhance the network’s average rate while satisfying the users’ demands.
Abstract This paper addresses the power allocation problem in a network where joint information-theoretic secrecy and covert communication are required. In this network, a single transmitter (Alice) sends information to two legitimate users (Bob and Carol). There is also an untrusted user who attempts to detect the content of Bob’s message and a warden (Willie) who wants to detect the existence of communication between Alice and the two users. Thus, Carol requires covert transmission, and Bob requires secure and covert communication. The network utilizes a friendly jammer to address these demands and overcome the low transmission rate of covert communication. To achieve covert communication, Alice sends both users’ data simultaneously in selected time slots to hide it from Willie, while the jammer continuously transmits signals in all time slots. The objective is to maximize the average transmission rate over the allocated powers of Bob, Carol, and the jammer while meeting the two users’ requirements. A novel iterative algorithm is proposed to obtain an effective solution. Simulation results indicate that the proposed method can enhance the network’s average rate while satisfying the users’ demands.
Abstract In this paper, we investigate joint information-theoretic security andcovert communication on a network in the presence of a single transmit-ter (Alice), a friendly jammer, a single untrusted user, two legitimateusers, and a single warden (Willie). In the considered network, one of theauthorized users, Bob, needs a secure communication, and therefore hismessage must be sent securely, and at the same time, the other autho-rized user, Carol, needs covert communication, i.e., the existence of hiscommunication with the transmitter should not be detected by the war-den, Willie. In the proposed network model, it is assumed that for covertcommunication requirements, Alice will use an on-off strategy to sendthe data to the legitimate receivers of the network, so that it decides onthe sending of data at any specific time slot. One of the main challengesin covert communication is low data rate because we have to reduce thetransmission power such that the main message gets to hide in back-ground noise. In the proposed network, a jammer is employed to destroy the eavesdropper and warden’s channel. To eliminate the interferencecreated by the jammer, it has been proposed that the used jammer in thenetwork be friendly. In this study, in addition to using joint security ofinformation theory and covert communication, we examine the averagetransmission rate according to the limitations and requirements of covertcommunication and the requested quality of service by users, by creatingartificial noise in the network which is generated by a friendly jammer.
In this article, we investigate joint information-theoretic secrecy and covert communication in a single-input-multioutput (SIMO) system where a transmitter (Alice) is communicating with two legitimate users (Bob and Carol). We consider that an untrusted user and a warden node are also present in the network attempting to attack the secure and covert communications to Bob and Carol, respectively. Specifically, Bob requires secure communications such that his messages from Alice are not decoded by the untrusted user, while Carol requires covert communications such that her messages from Alice are not detected by the warden. To do so, we consider that Alice transmits Carol's messages during selected time slots to hide them from the warden while also transmitting Bob's messages in each time slot contentiously. We formulate an optimization problem with the aim of maximizing the average rate subject to a covert communication requirement and a secure communications constraint. Since the proposed optimization problem is nonconvex, we utilize successive convex approximation to obtain a tractable solution. Moreover, we extend our proposed system model to multiple antenna Alice scenario and find beamforming vectors so that the average sum rate is maximized. Furthermore, we consider practical assumptions that Alice has imperfect knowledge of the warden's location and imperfect channel state information (CSI) of Bob and Carol. Our numerical examples highlight that the imperfect CSI at Carol has a more detrimental impact on the average rate compared to imperfect CSI at Bob.
In practice, Internet of Things (IoT) applications may face two different hostile attacks, i.e., overhearing the broadcasted data and detecting the presence of data communication. Previous works have assumed that only one of these attacks is present in the network and have addressed these attacks separately. In this article, we investigate the security of a simple but practical IoT-based point-to-point communication which is facing with the above-mentioned two attacks under some realistic assumptions. In other words, we aim to protect the data against two adversary nodes, namely Eve (who tries to capture the broadcasted data) and warden Willie (who tries to detect the presence of data communication between legitimate nodes). To tackle these attacks, we jointly employ the information-theoretic security and covert communication techniques. To hide information from Willies, we force the source to transmit its message in the selected time slot and the multiple-antennas cooperative jammer to inject jamming during all time slots contentiously which leads to deceive Eves and Willies jointly. To enhance the performance of this security design, we formulate an optimization problem, with the goal of maximizing the secrecy rate subject to power constraints at the source and jammer, while satisfying a covert communication requirement. Since the mentioned optimization problem is nonconvex, we propose an algorithm to solve it. Then, to obtain further insights, we extend our proposed system model to noncolluding and colluding Willies. Next, we study a practical communication scenario, where the source has uncertainty about Willie’s location and knows the channel state information (CSI) of Eves imperfectly. Our numerical results highlight that a more accurate estimation of Willie’s location has a more positive efficacy on the secrecy performance compared to the case with more accuracy of Eves’ CSI estimation.
In this paper, we address the problem of joint covert communication and secure transmission in untrusted relaying networks when multiple wardens exist in the network. We first consider a system model consisting of one source, one untrusted amplify-and-forward relay, one destination, and one warden. For covert communications, our aim is to prevent the warden from detecting the presence of communications via the source-relay-destination link. For secure transmission, our aim is to prevent the untrusted relay from decoding the source signal. To satisfy these requirements, we propose that the destination and the source inject jamming signals during the source-to-relay and relay-to-destination transmission phases, respectively. For the considered system model, we propose a power allocation strategy to maximize the secrecy rate and satisfy the covert requirements in both of the phases. Given that the proposed optimization problem is non-convex, we employ the successive convex approximation (SCA) approach to derive a tractable solution. To obtain further insights, we generalize our analytical results to consider multiple untrusted relays and multiple wardens. We focus on two scenarios of non-colluding and colluding wardens. Our results highlight that as the number of relays increases, the achievable secrecy rate increases while the average detection error probability decreases. This is a novel observation of a fundamental trade-off between covert requirement and secrecy performance.
Covert communication can hide confidential signals in environmental noise to avoid being detected and provide comprehensive security for wireless transmission. However, there still exists significant risks in the wireless transmission once being detected. In this paper, we propose a more secure covert scheme, where a multiple antennas transmitter assisted by a multi-antenna UAV jammer maximizes the covert secrecy rate under the scenarios of both correct and incorrect detection by a warden with both error detection probability and eavesdropping rate limitations satisfied. The transmitter and jammer adopt maximum ratio transmission (MRT) and zero-forcing to maximize the transmission rate and minimize the interference at the receiver, respectively. First, we analyze the monotonicity of error detection probability to determine the optimal power detection threshold and the corresponding largest error detection probability. Then, under this worst case, we jointly optimize the transmit and jamming power to maximize the covert secrecy rate while guaranteeing the covert and eavesdropping limits meet their respective requirements. Finally, simulation results are presented to prove the correctness of the theoretical conclusion and evaluate the effectiveness of our proposed scheme.
In this paper, we investigate the problem of secure communication with covert requirement in untrusted relaying networks. Our considered system model contains one source, one destination, one untrusted relay, and one Willie. The untrusted relay tries to extract the information signal, while the goal of Willie is to detect the presence of the information signal transmitted by the source, in the current time slot. To overcome these two attacks, it is assumed that the destination and the source inject jamming signal to the network in phase I and phase II, respectively. Accordingly, the communication in our proposed system model is accomplished in two phases. In the first phase, when the source transmits its data to the untrusted relay, the destination broadcasts its jamming signal. In the second phase, when the relay retransmits the received signal, the source transmits a jamming signal with one of its antennas. For this system model, we suggest a novel power allocation strategy to maximize the instantaneous secrecy rate subject to satisfying the covert requirements in both of the phases. Since the proposed optimization problem is non-convex, the Successive Convex Approximation (SCA) method is used to change it to a convex optimization problem. Numerical curves are presented to reveal the impact of the untrusted relay's location an number of source antennas on the secrecy performance.