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Related papers: An Insight to Covert Channels

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The primary objective of quantum Shannon theory is to evaluate the capacity of quantum channels. In spite of the existence of rigorous coding theorems that quantify the transmission of information through quantum channels, superadditivity…

Quantum Physics · Physics 2024-01-17 Rajiuddin Sk , Prasanta K. Panigrahi

We start with a short introduction to the roof concept. An elementary discussion of phase-damping channels shows the role of anti-linear operators in representing their concurrence. A general expression for some concurrences is derived. We…

Quantum Physics · Physics 2007-05-23 Armin Uhlmann

Internet censorship limits the access of nodes residing within a specific network environment to the public Internet, and vice versa. During the last decade, techniques for conducting Internet censorship have been developed further.…

Cryptography and Security · Computer Science 2025-10-31 Steffen Wendzel , Simon Volpert , Sebastian Zillien , Julia Lenz , Philip Rünz , Luca Caviglione

This paper continues the study of stochastic maps, or channels, which break entanglement. We give a detailed description of entanglement-breaking qubit channels, and show that such maps are precisely the convex hull of those known as…

Quantum Physics · Physics 2009-11-10 Mary Beth Ruskai

A quantum channel is said to be a mixed-unitary channel if it can be expressed as a convex combination of unitary channels. We prove that, given the Choi representation of a quantum channel, it is NP-hard with respect to polynomial-time…

Quantum Physics · Physics 2020-04-22 Colin Do-Yan Lee , John Watrous

This paper deals with the multiplicative finite-field matrix channel, a discrete memoryless channel whose input and output are matrices (over a finite field) related by a multiplicative transfer matrix. The model considered here assumes…

Information Theory · Computer Science 2013-04-19 Roberto W. Nóbrega , Danilo Silva , Bartolomeu F. Uchôa-Filho

We determine the optimal achievable rate at which entanglement can be reliably transmitted when the memoryless channel used during transmission is unknown both to sender and receiver. To be more precise, we assume that both of them only…

Quantum Physics · Physics 2009-04-21 Igor Bjelakovic , Holger Boche , Janis Noetzel

The problem of dephasing channel discrimination is addressed for finite-dimensional systems. In particular, the optimization with respect to input states without energy constraint is solved analytically for qubit, qutrit and ququart.…

Quantum Physics · Physics 2023-10-25 Milajiguli Rexiti , Laleh Memarzadeh , Stefano Mancini

The secrecy problem in the state-dependent cognitive interference channel is considered in this paper. In our model, there are a primary and a secondary (cognitive) transmitter-receiver pairs, in which the cognitive transmitter has the…

Information Theory · Computer Science 2016-05-19 Hamid G. Bafghi , Babak Seyfe , Mahtab Mirmohseni , Mohammad Reza Aref

We study covert classical communication over a quantum multiple-access channel (MAC) with a helper. Specifically, we consider three transmitters, where one transmitter helps the other two transmitters communicate covertly with a receiver.…

Information Theory · Computer Science 2025-12-03 Hassan ZivariFard , Rémi A. Chou , Xiaodong Wang

The efficiency of parameter estimation of quantum channels is studied in this paper. We introduce the concept of programmable parameters to the theory of estimation. It is found that programmable parameters obey the standard quantum limit…

Quantum Physics · Physics 2010-03-17 Zhengfeng Ji , Guoming Wang , Runyao Duan , Yuan Feng , Mingsheng Ying

Covert channel attacks have been continuously studied as severe threats to modern computing systems. Software-based covert channels are a typically hard-to-detect branch of these attacks, since they leverage virtual resources to establish…

Cryptography and Security · Computer Science 2024-09-23 Jeferson Gonzalez-Gomez , Jose Alejandro Ibarra-Campos , Jesus Yamir Sandoval-Morales , Lars Bauer , Jörg Henkel

We formulate and study, in general terms, the problem of quantum system identification, i.e., the determination (or estimation) of unknown quantum channels through their action on suitably chosen input density operators. We also present a…

Quantum Physics · Physics 2007-05-23 Maxim Raginsky

The capacity of discrete-time, non-coherent, multipath fading channels is considered. It is shown that if the delay spread is large in the sense that the variances of the path gains do not decay faster than geometrically, then capacity is…

Information Theory · Computer Science 2016-11-18 Tobias Koch , Amos Lapidoth

The problem of covert communication over Multiple-Input Multiple-Output (MIMO) Additive White Gaussian Noise (AWGN) channels is investigated, in which a transmitter attempts to reliably communicate with a legitimate receiver while avoiding…

Information Theory · Computer Science 2025-07-21 Shi-Yuan Wang , Matthieu R. Bloch

This paper studies on-chip communication with non-ideal heat sinks. A channel model is proposed where the variance of the additive noise depends on the weighted sum of the past channel input powers. It is shown that, depending on the…

Information Theory · Computer Science 2016-11-15 Tobias Koch , Amos Lapidoth , Paul P. Sotiriadis

In this chapter, I review the main methods and techniques of complex systems science. As a first step, I distinguish among the broad patterns which recur across complex systems, the topics complex systems science commonly studies, the tools…

Adaptation and Self-Organizing Systems · Physics 2007-05-23 Cosma Rohilla Shalizi

While capacities of discrete memoryless channels are well studied, it is still not possible to obtain a closed-form expression for the capacity of an arbitrary discrete memoryless channel. This paper describes an elementary technique based…

Information Theory · Computer Science 2020-01-08 Thuan Nguyen , Thinh Nguyen

Security protocols enable secure communication over insecure channels. Privacy protocols enable private interactions over secure channels. Security protocols set up secure channels using cryptographic primitives. Privacy protocols set up…

Cryptography and Security · Computer Science 2023-11-03 Jason Castiglione , Dusko Pavlovic , Peter-Michael Seidel

Leak detection systems range from simple, visual line walking and checking ones to complex arrangements of hard-ware and software. No one method is universally applicable and operating requirements dictate which method is the most cost…

Other Computer Science · Computer Science 2009-03-26 Timur Chis