Security is one of the most important issues in communications. Security issues arising in communication networks include confidentiality, integrity, authentication and non-repudiation. Attacks on the security of communication networks can be divided into two basic types: passive attacks and active attacks. An active attack corresponds to the situation in which a malicious actor intentionally disrupts the system. A passive attack corresponds to the situation in which a malicious actor attempts to interpret source information without injecting any information or trying to modify the information; i.e., passive attackers listen to the transmission without modifying it. Information Theoretic Security focuses on confidentiality issues, in which passive attacks are of primary concern. The information theoretic approach to achieving secure communication opens a promising new direction toward solving wireless networking security problems. Compared to contemporary cryptosystems, information theoretic approaches offer advantages such as eliminating the key management issue; are less vulnerable to the man-in-the-middle and achieve provable security that is robust to powerful eavesdroppers possessing unlimited computational resources, knowledge of the communication strategy employed including coding and decoding algorithms, and access to communication systems either through perfect or noisy channels. Information Theoretic Security surveys the research dating back to the 1970s which forms the basis of applying this technique in modern systems. It proceeds to provide an overview of how information theoretic approaches are developed to achieve secrecy for a basic wire-tap channel model as well as for its extensions to multiuser networks. It is an invaluable resource for students and researchers working in network security, information theory and communications.
Security is one of the most important issues in communications. Security issues arising in communication networks include confidentiality, integrity, authentication and non-repudiation. Attacks on the security of communication networks can be divided into two basic types: passive attacks and active attacks. An active attack corresponds to the situation in which a malicious actor intentionally disrupts the system. A passive attack corresponds to the situation in which a malicious actor attempts to interpret source information without injecting any information or trying to modify the information; i.e., passive attackers listen to the transmission without modifying it. Information Theoretic Security focuses on confidentiality issues, in which passive attacks are of primary concern. The information theoretic approach to achieving secure communication opens a promising new direction toward solving wireless networking security problems. Compared to contemporary cryptosystems, information theoretic approaches offer advantages such as eliminating the key management issue; are less vulnerable to the man-in-the-middle and achieve provable security that is robust to powerful eavesdroppers possessing unlimited computational resources, knowledge of the communication strategy employed including coding and decoding algorithms, and access to communication systems either through perfect or noisy channels. Information Theoretic Security surveys the research dating back to the 1970s which forms the basis of applying this technique in modern systems. It proceeds to provide an overview of how information theoretic approaches are developed to achieve secrecy for a basic wire-tap channel model as well as for its extensions to multiuser networks. It is an invaluable resource for students and researchers working in network security, information theory and communications.
The secure transport of messages was the concern of many early civilizations. Since then, different methods have been developed to assure that only the sender and the addressee would be able to read a message, while it would be illegible or without significant meaning to a third party. Today, this practice continues with more fervor. Wireless, wired, and optical communication networks are able to transport unimaginable amounts of data and thus privacy of information and security of the network are of the utmost concern because a good part of the transported information may be very sensitive and/or confidential. Confidentiality of information has been particularly popularized with the explosive growth of the Internet, which has touched most people's lives. However, from the outset, the Internet was based on open network architecture with computer-based nodes and without network security, and thus was vulnerable to attackers and hackers. Wireless networks transmit in unguarded space and thus are also subject to malicious actors. Dense wavelength-division multiplexing (DWDM) optical networks transport a massive aggregate traffic that has exceeded terabits per second per single fiber; therefore, the issues of information privacy and network security are equally important. As a result, the development of unbreakable cipher keys, cipher-key distribution, identification of malicious actors, source authentication, physical-link signature identification, countermeasures, and so forth has been the major thrust of research efforts with regard to cyber-security. This article focuses on cryptography, and is the first of a series of three articles on cryptography and security in communications. Subsequent articles will cover wireless and IP network security, as well as optical network security, quantum cryptography, and quantum-key distribution processes specific to optical networks.
The rapid growth in wireless communication systems has provided a flexibility of communication and content that has had a transformative impact to all aspects of society.However, the broadcast nature of the wireless medium makes these systems vulnerable to passive attacks in which the adversary attempts to eavesdrop on the transmitted messages, and to active attacks in which the adversary can intelligently manipulate legitimate transmissions, both of which can jeopardize a myriad of critical wireless services.Hence, it is imperative to design wireless networks with safeguards in place to ensure their resilience to attacks.To that end, this dissertation provides various perspectives in the domain of information theoretic secrecy and authentication, which provably guarantees security, regardless of the computational capabilities of the adversary.We strive to bridge the gap between the information theory of security and the practically implementable protocols within this paradigm.We first consider point to point secure communication over flat fading wireless channels under delay constraint.We extend the definition of outage capacity to account for the secrecy constraint and obtain sharp characterizations of the corresponding fundamental limits under different assumptions on the transmitter channel state information (CSI).The capacity achieving scheme relies on opportunistically exchanging private keys between the legitimate nodes.These keys are stored in a key buffer and used to secure delay sensitive data.We also characterize the optimal 4.5 Multiple Preauthenticated Helpers . . . . . . . . . . . . . . . . . . .
Secure communication ensures the integrity and confidentiality of communication between connected devices. An information-theoretic approach to secure communication gives the strongest confidentiality guarantee by assuming that the attacker has unlimited computing power. The earliest formal model and definition of information-theoretic secure communication is by Shannon, who employed a secret key shared between communicating parties to provide confidentiality. An alternative elegant information-theoretic approach to secure communication views the natural characteristics of the environment (i.e., channel’s noise) as a resource to build security functionalities. This approach was first proposed by Wyner, and the corresponding secure communication model is called the wiretap channel model. These two approaches introduce two primary resources for providing information-theoretic secure communication: the shared secret key and physical properties of the communication medium. In this thesis, we study how to employ the above two resources for secure message transmission. We study this by using channel’s noise in the wiretap channel model. In this model, a sender is connected to the receiver and the adversary through two noisy channels. We propose a new wiretap encoding scheme with strong secrecy that provides perfect secrecy and reliability, asymptotically. The construction treats the noise in the adversary’s channel as a source of randomness that is extracted and used to hide the message from the adversary. We realize the wiretap channel model using cooperative jamming to evaluate the performance of wiretap codes in practice. We consider a model called keyed wiretap channel that unifies Wyner’s model with Shannon’s model of perfect secrecy for information systems, and propose a keyed encoding schemes with strong secrecy and other properties that are attractive in practice. We also study two-party information-theoretic secret key agreement when the two parties have access to samples of a common source of randomness and use a single message transmission to arrive at a shared random key. We propose a secret key agreement protocol in this setting, prove its security, and show its superior performance compared to other known protocols with the same properties. Finally, we propose an information-theoretic secret key agreement over a virtual wiretap channel created by cooperative jamming.
Information theoretic approaches to security have been examined as a promising complement to current cryptographic techniques. Such information theoretic approaches establish reliable communication and data confidentiality directly at the physical layer of a communication network by taking the properties of the noisy channel into account leading to unconditional security regardless of the computational capabilities of eavesdroppers. The provision of accurate channel state information is a major challenge particularly in wireless communication systems, especially information about the channels to eavesdroppers. In addition, there might be malevolent adversaries who jam or influence the channel of the legitimate users. This paper surveys different models for secure communication under channel uncertainty and adversarial attacks and reviews the corresponding secrecy capacity results, which characterize the maximum rate at which information can be sent to legitimate receivers while being kept perfectly security from eavesdroppers.
Security issues for traditional wireless networks have been considered as a very important research area, and have taken a considerable attention for several years due to the broadcast nature of the wireless medium, which makes attacks more likely to happen than in wireline systems. Most of the studies in this area focus on the security in the higher layers in the protocol stack via the use of cryptography and key management. The main idea of these security approaches is based on the limited computational power of the eavesdroppers. With the advent of the infrastructureless networks such as mobile ad hoc networks (MANETs), further challenges have appeared which make the nodes more vulnerable to attacks. Among these challenges are the absence of centralized hardware for security problems, the multihop routes that the transmitted information should follow, and the power-limited terminals [152]. Therefore, to cope with these limitations, physical layer security (or informationtheoretic security) has gained a considerable attention in the last few years. The goal of physical layer security is to allow the source to confidentially communicate with the legitimate destination, while the eavesdropper cannot interpret the source information, without any assumption for the eavesdropper nodes such as the computational power, or the available information. From an information-theoretic standpoint, the achieved source-destination confidential rate is called the achievable secrecy rate.
This paper provides a comprehensive review of the domain of physical layer security in multiuser wireless networks. The essential premise of physical layer security is to enable the exchange of confidential messages over a wireless medium in the presence of unauthorized eavesdroppers, without relying on higher-layer encryption. This can be achieved primarily in two ways: without the need for a secret key by intelligently designing transmit coding strategies, or by exploiting the wireless communication medium to develop secret keys over public channels. The survey begins with an overview of the foundations dating back to the pioneering work of Shannon and Wyner on information-theoretic security. We then describe the evolution of secure transmission strategies from point-to-point channels to multiple-antenna systems, followed by generalizations to multiuser broadcast, multiple-access, interference, and relay networks. Secret-key generation and establishment protocols based on physical layer mechanisms are subsequently covered. Approaches for secrecy based on channel coding design are then examined, along with a description of inter-disciplinary approaches based on game theory and stochastic geometry. The associated problem of physical layer message authentication is also briefly introduced. The survey concludes with observations on potential research directions in this area.