The Experts below are selected from a list of 5088 Experts worldwide ranked by ideXlab platform
Si-hyeon Lee - One of the best experts on this subject based on the ideXlab platform.
-
treating interference as noise is optimal for Covert Communication over interference channels
International Symposium on Information Theory, 2020Co-Authors: Kanghee Cho, Si-hyeon LeeAbstract:In this paper, the Covert Communication scenario over K-user-pair discrete memoryless interference channels with a warden is studied. We assume that the wardens channel output distribution induced by K "off input symbols, which are sent when no Communication occurs, is not a convex combination of those induced by any other combination of input symbols (otherwise, the square-root law does not hold). We derive the exact Covert capacity region and show that a simple point-topoint based scheme with treating interference as noise is optimal. In addition, we analyze the secret key length required for the reliable and Covert Communication with the desired rates, and present a channel condition where the secret key between each user pair is unnecessary.
-
Treating Interference as Noise is Optimal for Covert Communication over Interference Channels
arXiv: Information Theory, 2020Co-Authors: Kanghee Cho, Si-hyeon LeeAbstract:We study the Covert Communication over K-user discrete memoryless interference channels (DM-ICs) with a warden. It is assumed that the warden's channel output distribution induced by K "off" input symbols, which are sent when no Communication occurs, is not a convex combination of those induced by any other combination of input symbols (otherwise, the square-root law does not hold). We derive the exact Covert capacity region and show that a simple point-to-point based scheme with treating interference as noise is optimal. In addition, we analyze the secret key length required for the reliable and Covert Communication with the desired rates, and present a channel condition where a secret key between each user pair is unnecessary. The results are extended to the Gaussian case and the case with multiple wardens.
-
ISIT - Treating Interference as Noise is Optimal for Covert Communication over Interference Channels
2020 IEEE International Symposium on Information Theory (ISIT), 2020Co-Authors: Kanghee Cho, Si-hyeon LeeAbstract:In this paper, the Covert Communication scenario over K-user-pair discrete memoryless interference channels with a warden is studied. We assume that the wardens channel output distribution induced by K "off input symbols, which are sent when no Communication occurs, is not a convex combination of those induced by any other combination of input symbols (otherwise, the square-root law does not hold). We derive the exact Covert capacity region and show that a simple point-topoint based scheme with treating interference as noise is optimal. In addition, we analyze the secret key length required for the reliable and Covert Communication with the desired rates, and present a channel condition where the secret key between each user pair is unnecessary.
-
Covert Communication With Channel-State Information at the Transmitter
IEEE Transactions on Information Forensics and Security, 2018Co-Authors: Si-hyeon Lee, Ligong Wang, Ashish Khisti, Gregory WornellAbstract:We consider the problem of Covert Communication over a state-dependent channel, where the transmitter has causal or noncausal knowledge of the channel states. Here, Covert means that a warden on the channel should observe similar statistics when the transmitter is sending a message and when it is not. When a sufficiently long secret key is shared between the transmitter and the receiver, we derive closed-form formulas for the maximum achievable Covert Communication rate (Covert capacity) for discrete memoryless channels and, when the transmitter's channel-state information (CSI) is noncausal, for additive white Gaussian noise (AWGN) channels. For certain channel models, including the AWGN channel, we show that the Covert capacity is positive with CSI at the transmitter, but is zero without CSI. We also derive lower bounds on the rate of the secret key that is needed for the transmitter and the receiver to achieve the Covert capacity. Index Terms— Covert Communication, low probability of detection, channel uncertainty, channel-state information at the transmitter, likelihood encoding.
-
Covert Communication With Channel-State Information at the Transmitter
IEEE Transactions on Information Forensics and Security, 2018Co-Authors: Si-hyeon Lee, Ligong Wang, Ashish Khisti, Gregory WornellAbstract:We consider the problem of Covert Communication over a state-dependent channel, where the transmitter has causal or noncausal knowledge of the channel states. Here, Covert means that a warden on the channel should observe similar statistics when the transmitter is sending a message and when it is not. When a sufficiently long secret key is shared between the transmitter and the receiver, we derive closed-form formulas for the maximum achievable Covert Communication rate (Covert capacity) for discrete memoryless channels and, when the transmitter’s channel-state information (CSI) is noncausal, for additive white Gaussian noise (AWGN) channels. For certain channel models, including the AWGN channel, we show that the Covert capacity is positive with CSI at the transmitter, but is zero without CSI. We also derive lower bounds on the rate of the secret key that is needed for the transmitter and the receiver to achieve the Covert capacity.
Sidharth Jaggi - One of the best experts on this subject based on the ideXlab platform.
-
Covert Communication With Polynomial Computational Complexity
IEEE Transactions on Information Theory, 2020Co-Authors: Qiaosheng Zhang, Mayank Bakshi, Sidharth JaggiAbstract:This paper develops a concatenated coding scheme with polynomial computational complexity for Covert Communication over Binary Symmetric Channels (BSCs) and binary-input Discrete Memoryless Channels (DMCs). Our setting is as follows — a transmitter Alice wishes to potentially reliably transmit a message to a receiver Bob, while ensuring that the transmission taking place is Covert with respect to a warden Willie (who hears Alice’s transmission over another independent channel). Prior works showed that Alice can reliably and Covertly transmit $\mathcal {O}(\sqrt {{n}})$ message bits over n channel uses, but one drawback is that the computational complexity of the codes designed scales as $2^{\Theta (\sqrt {{n}})}$ . In this work we provide a capacity-achiveing coding scheme with provable guarantees on both reliability and Covertness, and its computational complexity grows polynomially in the blocklength n .
-
Undetectable Radios: Covert Communication under Spectral Mask Constraints
2019Co-Authors: Qiaosheng Eric Zhang, Matthieu Bloch, Mayank Bakshi, Sidharth JaggiAbstract:We consider the problem of Covert Communication over continuous-time additive white Gaussian noise (AWGN) channels under spectral mask constraints. In addition to requiring the legitimate receiver to reliably decode, Covert Communication also requires that the warden is unable to estimate whether or not Communication is taking place. The spectral mask at the transmitter restricts excessive radiation beyond the bandwidth of interest. We develop a Communication scheme with theoretical guarantees for both Covertness and reliability, based on pulse amplitude modulation (PAM) with Binary Phase Shift Keying (BPSK) and root raised cosine (RRC) carrier pulses. Given a fixed time T and a spectral mask with bandwidth parameter W, √ we show that one can transmit O( W T ) bits of information Covertly and reliably, and our proposed scheme provides a lower bound on the Covert capacity.
-
undetectable radios Covert Communication under spectral mask constraints
International Symposium on Information Theory, 2019Co-Authors: Qiaosheng Eric Zhang, Matthieu R. Bloch, Mayank Bakshi, Sidharth JaggiAbstract:We consider the problem of Covert Communication over continuous-time additive white Gaussian noise (AWGN) channels under spectral mask constraints. In addition to requiring the legitimate receiver to reliably decode, Covert Communication also requires that the warden is unable to estimate whether or not Communication is taking place. The spectral mask at the transmitter restricts excessive radiation beyond the bandwidth of interest. We develop a Communication scheme with theoretical guarantees for both Covertness and reliability, based on pulse amplitude modulation (PAM) with Binary Phase Shift Keying (BPSK) and root raised cosine (RRC) carrier pulses. Given a fixed time T and a spectral mask with bandwidth parameter W, we show that one can transmit $\mathcal{O}\left( {\sqrt {WT} } \right)$ bits of information Covertly and reliably, and our proposed scheme provides a lower bound on the Covert capacity.
-
ISIT - Undetectable Radios: Covert Communication under Spectral Mask Constraints
2019 IEEE International Symposium on Information Theory (ISIT), 2019Co-Authors: Qiaosheng Eric Zhang, Matthieu R. Bloch, Mayank Bakshi, Sidharth JaggiAbstract:We consider the problem of Covert Communication over continuous-time additive white Gaussian noise (AWGN) channels under spectral mask constraints. In addition to requiring the legitimate receiver to reliably decode, Covert Communication also requires that the warden is unable to estimate whether or not Communication is taking place. The spectral mask at the transmitter restricts excessive radiation beyond the bandwidth of interest. We develop a Communication scheme with theoretical guarantees for both Covertness and reliability, based on pulse amplitude modulation (PAM) with Binary Phase Shift Keying (BPSK) and root raised cosine (RRC) carrier pulses. Given a fixed time T and a spectral mask with bandwidth parameter W, we show that one can transmit $\mathcal{O}\left( {\sqrt {WT} } \right)$ bits of information Covertly and reliably, and our proposed scheme provides a lower bound on the Covert capacity.
-
Computationally Efficient Covert Communication.
arXiv: Information Theory, 2016Co-Authors: Qiaosheng Zhang, Mayank Bakshi, Sidharth JaggiAbstract:In this paper, we design the first computationally efficient codes for simultaneously reliable and Covert Communication over Binary Symmetric Channels (BSCs). Our setting is as follows: a transmitter Alice wishes to potentially reliably transmit a message to a receiver Bob, while ensuring that the transmission taking place is Covert with respect to an eavesdropper Willie (who hears Alice's transmission over a noisier BSC). Prior works show that Alice can reliably and Covertly transmit O(\sqrt{n}) bits over n channel uses without any shared secret between Alice and Bob. One drawback of prior works is that the computational complexity of the codes designed scales as 2^{\Theta(\sqrt{n})}. In this work we provide the first computationally tractable codes with provable guarantees on both reliability and Covertness, while simultaneously achieving the best known throughput for the problem.
Matthieu R. Bloch - One of the best experts on this subject based on the ideXlab platform.
-
Keyless Covert Communication via Channel State Information
arXiv: Information Theory, 2020Co-Authors: Hassan Zivarifard, Matthieu R. Bloch, Aria NosratiniaAbstract:We consider the problem of Covert Communication over a state-dependent channel when the channel state is available either non-causally, causally, or strictly causally, either at the transmitter alone or at both transmitter and receiver. Covert Communication with respect to an adversary, called "warden," is one in which, despite Communication over the channel, the warden's observation remains indistinguishable from an output induced by innocent channel-input symbols. Covert Communication involves fooling an adversary in part by a proliferation of codebooks; for reliable decoding at the legitimate receiver, the codebook uncertainty is typically removed via a shared secret key that is unavailable to the warden. In contrast to previous work, we do not assume the availability of a shared key at the transmitter and legitimate receiver. Instead, shared randomness is extracted from the channel state in a manner that keeps it secret from the warden, despite the influence of the channel state on the warden's output. When channel state is available at the transmitter and receiver, we derive the Covert capacity region. When channel state is only available at the transmitter, we derive inner and outer bounds on the Covert capacity. We provide examples for which the Covert capacity is positive with knowledge of channel state information but is zero without it.
-
undetectable radios Covert Communication under spectral mask constraints
International Symposium on Information Theory, 2019Co-Authors: Qiaosheng Eric Zhang, Matthieu R. Bloch, Mayank Bakshi, Sidharth JaggiAbstract:We consider the problem of Covert Communication over continuous-time additive white Gaussian noise (AWGN) channels under spectral mask constraints. In addition to requiring the legitimate receiver to reliably decode, Covert Communication also requires that the warden is unable to estimate whether or not Communication is taking place. The spectral mask at the transmitter restricts excessive radiation beyond the bandwidth of interest. We develop a Communication scheme with theoretical guarantees for both Covertness and reliability, based on pulse amplitude modulation (PAM) with Binary Phase Shift Keying (BPSK) and root raised cosine (RRC) carrier pulses. Given a fixed time T and a spectral mask with bandwidth parameter W, we show that one can transmit $\mathcal{O}\left( {\sqrt {WT} } \right)$ bits of information Covertly and reliably, and our proposed scheme provides a lower bound on the Covert capacity.
-
ITW - Keyless Covert Communication in the Presence of Non-causal Channel State Information
2019 IEEE Information Theory Workshop (ITW), 2019Co-Authors: Hassan Zivarifard, Matthieu R. Bloch, Aria NosratiniaAbstract:We consider the problem of Covert Communication over a state-dependent channel, for which the transmitter and the legitimate receiver have non-causal access to the channel state information. Covert Communication with respect to an adversary, referred to as the “warden,” is one in which the distribution induced during Communication at the channel output observed by the warden is identical to the output distribution conditioned on an inactive channel-input symbol. Covert Communication involves fooling an adversary in part by a proliferation of codebooks; for reliable decoding at the legitimate receiver the codebook uncertainty is removed via a shared secret key that is unavailable to the warden. Unlike earlier work in state-dependent Covert Communication, we do not assume the availability of a shared key at the transmitter and legitimate receiver. Rather, a shared randomness is extracted at the transmitter and the receiver from the channel state, in a manner that keeps the shared randomness secret from the warden despite the influence of the channel state on the warden’s output. An inner bound on the Covert capacity, in the absence of an externally provided secret key, is derived.
-
ISIT - Undetectable Radios: Covert Communication under Spectral Mask Constraints
2019 IEEE International Symposium on Information Theory (ISIT), 2019Co-Authors: Qiaosheng Eric Zhang, Matthieu R. Bloch, Mayank Bakshi, Sidharth JaggiAbstract:We consider the problem of Covert Communication over continuous-time additive white Gaussian noise (AWGN) channels under spectral mask constraints. In addition to requiring the legitimate receiver to reliably decode, Covert Communication also requires that the warden is unable to estimate whether or not Communication is taking place. The spectral mask at the transmitter restricts excessive radiation beyond the bandwidth of interest. We develop a Communication scheme with theoretical guarantees for both Covertness and reliability, based on pulse amplitude modulation (PAM) with Binary Phase Shift Keying (BPSK) and root raised cosine (RRC) carrier pulses. Given a fixed time T and a spectral mask with bandwidth parameter W, we show that one can transmit $\mathcal{O}\left( {\sqrt {WT} } \right)$ bits of information Covertly and reliably, and our proposed scheme provides a lower bound on the Covert capacity.
-
Allerton - Covert Communication with Unknown Code at the Warden
2019 57th Annual Allerton Conference on Communication Control and Computing (Allerton), 2019Co-Authors: Mehrdad Tahmasbi, Matthieu R. BlochAbstract:In Covert Communication, a transmitter attempts to send a message over a channel while avoiding detection from a warden. We investigate here how the warden’s knowledge of the code used by the transmitter and the receiver influences the optimal number of bits that can be Covertly and reliably sent. We formulate the problem in three scenarios: the warden completely knows the code, the warden knows only the rate and an upper-bound on the probability of error at the decoder, and the warden has access to previous samples of its channel when the code was used. The first scenario corresponds to the standard model in Covert Communication. For the second scenario, we characterize the number of bits that can be transmitted reliably subject to a Covertness constraint up to the first-order of asymptotics. Finally, for the third scenario, we provide lower-and upper-bound on the number of bits that can be transmitted reliably subject to a Covertness constraint for two scalings of the number of observed samples.
Saikat Guha - One of the best experts on this subject based on the ideXlab platform.
-
Fundamental Limits of Quantum-Secure Covert Communication Over Bosonic Channels
IEEE Journal on Selected Areas in Communications, 2020Co-Authors: Michael S. Bullock, Saikat Guha, Christos N. Gagatsos, Boulat A BashAbstract:We investigate the fundamental limit of quantumsecure Covert Communication over the lossy thermal noise bosonic channel, the quantum-mechanical model underlying many practical channels. We assume that the adversary has unlimited quantum information processing capabilities as well as access to all transmitted photons that do not reach the legitimate receiver. Given existence of noise that is uncontrolled by the adversary, the square root law (SRL) governs Covert Communication: up to c√n Covert bits can be transmitted reliably in n channel uses. Attempting to surpass this limit results in detection with unity probability as n → ∞. Here we present the expression for c, characterizing the SRL for the bosonic channel. We also prove that discrete-valued coherent state quadrature phase shift keying (QPSK) constellation achieves the optimal c, which is the same as that achieved by a circularly-symmetric complex-valued Gaussian prior on coherent state amplitude. Finally, while binary phase shift keying (BPSK) achieves the Holevo capacity for non-Covert bosonic channels in the low received signal-to-noise ratio regime, we show that it is strictly sub-optimal for Covert Communication.
-
Fundamental limits of quantum-secure Covert Communication over bosonic channels
arXiv: Information Theory, 2019Co-Authors: Michael S. Bullock, Saikat Guha, Christos N. Gagatsos, Boulat A BashAbstract:We investigate the fundamental limit of quantum-secure Covert Communication over the lossy thermal noise bosonic channel, the quantum-mechanical model underlying many practical channels. We assume that the adversary has unlimited quantum information processing capabilities as well as access to all transmitted photons that do not reach the legitimate receiver. Given existence of noise that is uncontrolled by the adversary, the square root law (SRL) governs Covert Communication: up to c*sqrt{n} Covert bits can be transmitted reliably in n channel uses. Attempting to surpass this limit results in detection with unity probability as n approaches infinity. Here we present the expression for c, characterizing the SRL for the bosonic channel. We also prove that discrete-valued coherent state quadrature phase shift keying (QPSK) constellation achieves the optimal c, which is the same as that achieved by a circularly-symmetric complex-valued Gaussian prior on coherent state amplitude. Finally, while binary phase shift keying (BPSK) achieves the Holevo capacity for non-Covert bosonic channels in the low received signal-to-noise ratio regime, we show that it is strictly sub-optimal for Covert Communication.
-
Allerton - Fundamental Limits of Quantum-Secure Covert Communication over Bosonic Channels
2019 57th Annual Allerton Conference on Communication Control and Computing (Allerton), 2019Co-Authors: Michael S. Bullock, Saikat Guha, Christos N. Gagatsos, Boulat A BashAbstract:We investigate the fundamental limit of quantumsecure Covert Communication over the lossy thermal noise bosonic channel, the quantum-mechanical mode underlying many practical channels. We assume that the adversary has unlimited quantum information processing capabilities as well as access to all transmitted photons that do not reach the legitimate receiver. Given existence of noise that is uncontrolled by the adversary, the square root law (SRL) governs Covert Communication: up to $c\sqrt {n}$ Covert bits can be transmitted reliably in $n$ channel uses. Attempting to surpass this limit results in detection with unity probability as $ n\rightarrow \infty $. Here we present the expression for $c$, characterizing the SRL for the bosonic channel. We also prove that discrete-valued coherent state quadrature phase shift keying (QPSK) constellation achieves the optimal $c,$ which is the same as that achieved by a circularly-symmetric complex-valued Gaussian prior on coherent state amplitude. Finally, while binary phase shift keying (BPSK) achieves the Holevo capacity for non-Covert bosonic channels in the low received signal-to-noise ratio regime, we show that it is strictly sub-optimal for Covert Communication.
-
Covert Communication over classical quantum channels
International Symposium on Information Theory, 2016Co-Authors: Azadeh Sheikholeslami, Boulat A Bash, Don Towsley, Dennis Goeckel, Saikat GuhaAbstract:Recently, the fundamental limits of Covert, i.e., reliable-yet-undetectable, Communication have been established for general memoryless channels and for lossy-noisy bosonic (quantum) channels with a quantum-limited adversary. The key import of these results was the square-root law (SRL) for Covert Communication, which states that O(√n) Covert bits, but no more, can be reliably transmitted over n channel uses with O(√n) bits of secret pre-shared between communicating parties. Here we prove the achievability of the SRL for a general memoryless classical-quantum channel, showing that SRL Covert Communication is achievable over any quantum Communication channel with a product-state transmission strategy. We leave open the converse, which, if proven, would show that even using entangled transmissions and entangling measurements, the SRL for Covert Communication cannot be surpassed over an arbitrary quantum channel.
-
Covert Communication over Classical-Quantum Channels
arXiv: Quantum Physics, 2016Co-Authors: Azadeh Sheikholeslami, Boulat A Bash, Don Towsley, Dennis Goeckel, Saikat GuhaAbstract:The square root law (SRL) is the fundamental limit of Covert Communication over classical memoryless channels (with a classical adversary) and quantum lossy-noisy bosonic channels (with a quantum-powerful adversary). The SRL states that $\mathcal{O}(\sqrt{n})$ Covert bits, but no more, can be reliably transmitted in $n$ channel uses with $\mathcal{O}(\sqrt{n})$ bits of secret pre-shared between the communicating parties. Here we investigate Covert Communication over general memoryless classical-quantum (cq) channels with fixed finite-size input alphabets, and show that the SRL governs Covert Communications in typical scenarios. %This demonstrates that the SRL is achievable over any quantum Communications channel using a product-state transmission strategy, where the transmitted symbols in every channel use are drawn from a fixed finite-size alphabet. We characterize the optimal constants in front of $\sqrt{n}$ for the reliably communicated Covert bits, as well as for the number of the pre-shared secret bits consumed. We assume a quantum-powerful adversary that can perform an arbitrary joint (entangling) measurement on all $n$ channel uses. However, we analyze the legitimate receiver that is able to employ a joint measurement as well as one that is restricted to performing a sequence of measurements on each of $n$ channel uses (product measurement). We also evaluate the scenarios where Covert Communication is not governed by the SRL.
Qiaosheng Eric Zhang - One of the best experts on this subject based on the ideXlab platform.
-
Undetectable Radios: Covert Communication under Spectral Mask Constraints
2019Co-Authors: Qiaosheng Eric Zhang, Matthieu Bloch, Mayank Bakshi, Sidharth JaggiAbstract:We consider the problem of Covert Communication over continuous-time additive white Gaussian noise (AWGN) channels under spectral mask constraints. In addition to requiring the legitimate receiver to reliably decode, Covert Communication also requires that the warden is unable to estimate whether or not Communication is taking place. The spectral mask at the transmitter restricts excessive radiation beyond the bandwidth of interest. We develop a Communication scheme with theoretical guarantees for both Covertness and reliability, based on pulse amplitude modulation (PAM) with Binary Phase Shift Keying (BPSK) and root raised cosine (RRC) carrier pulses. Given a fixed time T and a spectral mask with bandwidth parameter W, √ we show that one can transmit O( W T ) bits of information Covertly and reliably, and our proposed scheme provides a lower bound on the Covert capacity.
-
undetectable radios Covert Communication under spectral mask constraints
International Symposium on Information Theory, 2019Co-Authors: Qiaosheng Eric Zhang, Matthieu R. Bloch, Mayank Bakshi, Sidharth JaggiAbstract:We consider the problem of Covert Communication over continuous-time additive white Gaussian noise (AWGN) channels under spectral mask constraints. In addition to requiring the legitimate receiver to reliably decode, Covert Communication also requires that the warden is unable to estimate whether or not Communication is taking place. The spectral mask at the transmitter restricts excessive radiation beyond the bandwidth of interest. We develop a Communication scheme with theoretical guarantees for both Covertness and reliability, based on pulse amplitude modulation (PAM) with Binary Phase Shift Keying (BPSK) and root raised cosine (RRC) carrier pulses. Given a fixed time T and a spectral mask with bandwidth parameter W, we show that one can transmit $\mathcal{O}\left( {\sqrt {WT} } \right)$ bits of information Covertly and reliably, and our proposed scheme provides a lower bound on the Covert capacity.
-
ISIT - Undetectable Radios: Covert Communication under Spectral Mask Constraints
2019 IEEE International Symposium on Information Theory (ISIT), 2019Co-Authors: Qiaosheng Eric Zhang, Matthieu R. Bloch, Mayank Bakshi, Sidharth JaggiAbstract:We consider the problem of Covert Communication over continuous-time additive white Gaussian noise (AWGN) channels under spectral mask constraints. In addition to requiring the legitimate receiver to reliably decode, Covert Communication also requires that the warden is unable to estimate whether or not Communication is taking place. The spectral mask at the transmitter restricts excessive radiation beyond the bandwidth of interest. We develop a Communication scheme with theoretical guarantees for both Covertness and reliability, based on pulse amplitude modulation (PAM) with Binary Phase Shift Keying (BPSK) and root raised cosine (RRC) carrier pulses. Given a fixed time T and a spectral mask with bandwidth parameter W, we show that one can transmit $\mathcal{O}\left( {\sqrt {WT} } \right)$ bits of information Covertly and reliably, and our proposed scheme provides a lower bound on the Covert capacity.
