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27
Information and Computation: Classical and Quantum Aspects
 REVIEWS OF MODERN PHYSICS
, 2001
"... Quantum theory has found a new field of applications in the realm of information and computation during the recent years. This paper reviews how quantum physics allows information coding in classically unexpected and subtle nonlocal ways, as well as information processing with an efficiency largely ..."
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Cited by 23 (2 self)
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Quantum theory has found a new field of applications in the realm of information and computation during the recent years. This paper reviews how quantum physics allows information coding in classically unexpected and subtle nonlocal ways, as well as information processing with an efficiency largely surpassing that of the present and foreseeable classical computers. Some outstanding aspects of classical and quantum information theory will be addressed here. Quantum teleportation, dense coding, and quantum cryptography are discussed as a few samples of the impact of quanta in the transmission of information. Quantum logic gates and quantum algorithms are also discussed as instances of the improvement in information processing by a quantum computer. We provide finally some examples of current experimental
JAMRESISTANT COMMUNICATION WITHOUT SHARED SECRETS THROUGH THE USE OF CONCURRENT CODES
, 2007
"... We consider the problem of establishing jamresistant, wireless, omnidirectional communication channels when there is no initial shared secret. No existing system achieves this. We propose a general algorithm for this problem, the BBC algorithm, and give several instantiations of it. We develop an ..."
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Cited by 16 (9 self)
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We consider the problem of establishing jamresistant, wireless, omnidirectional communication channels when there is no initial shared secret. No existing system achieves this. We propose a general algorithm for this problem, the BBC algorithm, and give several instantiations of it. We develop and analyze this algorithm within the framework of a new type of code, concurrent codes, which are those superimposed codes that allow efficient decoding. Finally, we propose the Universal Concurrent Code algorithm, and prove that it covers all possible concurrent codes, and give connections between its theory and that of monotone Boolean functions.
Keyless jam resistance
 in Proc. 8th Annual IEEE SMC Information Assurance Workshop (IAW
, 2007
"... Traditionally, omnidirectional, radio frequency (RF) communication has been made resistant to jamming by the use of a secret key that is shared by the sender and receiver. There are no known methods for achieving jam resistance without that shared key. Unfortunately, wireless communication is now re ..."
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Cited by 15 (5 self)
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Traditionally, omnidirectional, radio frequency (RF) communication has been made resistant to jamming by the use of a secret key that is shared by the sender and receiver. There are no known methods for achieving jam resistance without that shared key. Unfortunately, wireless communication is now reaching a scale and a level of importance where such secretkey systems are becoming impractical. For example, the civilian side of the Global Positioning System (GPS) cannot use a shared secret, since that secret would have to be given to all 6.5 billion potential users, and so would no longer be secret. So civilian GPS cannot currently be protected from jamming. But the FAA has stated that the civilian airline industry will transition to using GPS for all navigational aids, even during landings. A terrorist with a simple jamming system could wreak havoc at a major airport. No existing system can solve this problem, and the problem itself has not even been widely discussed. The problem of keyless jam resistance is important. There is a great need for a system that can broadcast messages without any prior secret shared between the sender and receiver. We propose the first system for keyless jam resistance: the BBC algorithm. We describe the encoding, decoding, and broadcast algorithms. We then analyze it for expected resistance to jamming and error rates. We show that BBC can achieve the same level of jam resistance as traditional spread spectrum systems, at just under half the bit rate, and with no shared secret. Furthermore, a hybrid system can achieve the same average bit rate as traditional systems. I.
Cryptography and Evidence
, 1997
"... The invention of publickey cryptography led to the notion that cryptographically protected messages could be used as evidence to convince an impartial adjudicator that a disputed event had in fact occurred. Information stored in a computer is easily modi ed, and so records can be falsi ed or retros ..."
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Cited by 14 (0 self)
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The invention of publickey cryptography led to the notion that cryptographically protected messages could be used as evidence to convince an impartial adjudicator that a disputed event had in fact occurred. Information stored in a computer is easily modi ed, and so records can be falsi ed or retrospectively modi ed. Cryptographic protection prevents modi cation, and it is hoped that this will make cryptographically protected data acceptable as evidence. This usage of cryptography to render an event undeniable has become known as nonrepudiation. This dissertation is an enquiry into the fundamental limitations of this application of cryptography, and the disadvantages of the techniques which are currently in use. In the course of this investigation I consider the converse problem, of ensuring that an instance of communication between computer systems leaves behind no unequivocal evidence of its having taken place. Features of communications protocols that were seen as defects from the standpoint of nonrepudiation can be seen as bene ts from the standpoint of this converse problem, which I call \plausible deniability". i Declaration This dissertation is the result of my own work and includes nothing which is the outcome of work done in collaboration. This dissertation is not substantially the same as any other that I have submitted for a degree, diploma, or other quali cation at any other university. Acknowledgements Iwould like to thank Peter Kirstein and Ben Bacarisse for managing the research projects which caused me to become interested in this area; Steve Kent for many interesting discussions about the problems of key certi cation; Russ Housley for suggesting the term \plausible deniability"; Roger Needham for being my supervisor; and Bruce Christianson for his advice on how to write a dissertation. ii To my grandfather,
Jam resistant communications without shared secrets
 in Proceedings of the 3 rd International Conference on Information Warfare and Security
, 2008
"... Distribution A, Approved for public release, distribution unlimited Abstract. We consider the problem of establishing jamresistant, wireless, omnidirectional communication channels when there is no initial shared secret. No existing system achieves this. We propose a general algorithm for this prob ..."
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Cited by 10 (1 self)
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Distribution A, Approved for public release, distribution unlimited Abstract. We consider the problem of establishing jamresistant, wireless, omnidirectional communication channels when there is no initial shared secret. No existing system achieves this. We propose a general algorithm for this problem, the BBC algorithm, and give several instantiations of it. We develop and analyze this algorithm within the framework of a new type of code, concurrent codes, which are those superimposed codes that allow efficient decoding. Finally, we propose the Universal Concurrent Code algorithm, and prove that it covers all possible concurrent codes, and give connections between its theory and that of monotone Boolean functions.
FineGrain Configurability for Secure Communication
, 2000
"... Current solutions for providing communication security in network applications allow customization of certain security attributes and techniques, but in limited ways and without the benefit of a single unifying framework. Here, the design of a highlycustomizable extensible service called SecComm ..."
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Cited by 9 (3 self)
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Current solutions for providing communication security in network applications allow customization of certain security attributes and techniques, but in limited ways and without the benefit of a single unifying framework. Here, the design of a highlycustomizable extensible service called SecComm is described in which attributes such as authenticity, privacy, integrity, and nonrepudiation can be customized in arbitrary ways. With SecComm, applications can open secure communication connections in which only those attributes selected from among a wide range of possibilities are enforced, and are enforced using the strength or technique desired. SecComm has been implemented using Cactus, a system for building configurable communication services. In Cactus, different properties and techniques are implemented as software modules called microprotocols that interact using an eventdriven execution paradigm. This nonhierarchical design approach has a high degree of flexibility, ye...
Symmetric and asymmetric encryption
 ACM Computing Surveys
, 1979
"... All cryptosystems currently m use are symmetrm m the sense that they require the transmitter and receiver to share, m secret, either the same pmce of reformation (key) or one of a paLr of related keys easdy computed from each other, the key is used m the encryption process to introduce uncertainty t ..."
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Cited by 8 (0 self)
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All cryptosystems currently m use are symmetrm m the sense that they require the transmitter and receiver to share, m secret, either the same pmce of reformation (key) or one of a paLr of related keys easdy computed from each other, the key is used m the encryption process to introduce uncertainty to an unauthorized receiver. Not only is an
Quantum information processing: cryptography, computation, and teleportation
 Proceedings of the IEEE
, 1996
"... Present information technology is based on the laws of classical physics. However, advances in quantum physics have stimulated interest in its potential impact on such technology. This article is a reasonably introductory review of three aspects of quantum information processing, cryptography, compu ..."
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Cited by 7 (0 self)
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Present information technology is based on the laws of classical physics. However, advances in quantum physics have stimulated interest in its potential impact on such technology. This article is a reasonably introductory review of three aspects of quantum information processing, cryptography, computation, and feleportation. In order to give a level of selfcontainment, I serve up hors d ' oeuvres on the relevant parts of quantum physics and the sorts of quantum systems which might form the building blocks for quantum processors. Quantum cryptography utilizes states of individual quantum systems for the transfer of conventional classical bits of information. The impossibility of measuring quantum systems without disturbing them guarantees the detection of eavesdropping and hence secure information transfer is possible. In a sense, tdeportation is the inverse of cryptography, using more robust classical bits to faithfully transfer a quantum state through a noisy environment. Quantum computation utilizes the evolving quantum state of a complex system. which consists of many interacting individuals. If such a machine could be built, it would be capable of solving some problems which are intractable on any conventional computer; I illustrate this with Shor's quantum factoring algorithm. I give some details of the current experimental achievements, proposals, and prospects for the future and of the patents granted to date. L
Cryptology
"... Cryptology has advanced tremendously since 1976; this chapter provides a brief overview of the current stateoftheart in the field. Several major themes predominate in the development. One such theme is the careful elaboration of the definition of security for a cryptosystem. A second theme has be ..."
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Cited by 1 (0 self)
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Cryptology has advanced tremendously since 1976; this chapter provides a brief overview of the current stateoftheart in the field. Several major themes predominate in the development. One such theme is the careful elaboration of the definition of security for a cryptosystem. A second theme has been the search for provably secure cryptosystems, based on plausible assumptions about the difficulty of specific numbertheoretic problems or on the existence of certain kinds of functions (such as oneway functions). A third theme is the invention of many novel and surprising cryptographic capabilities, such as publickey cryptography, digital signatures, secretsharing, oblivious transfers, and zeroknowledge proofs. These themes have been developed and interwoven so that today theorems of breathtaking generality and power assert the existence of cryptographic techniques capable of solving almost any imaginable cryptographic problem.
The Evolution of Cryptography From Caesar To RSA: Investigations in the Flaws and Advantages
"... This paper examines the practical utility of RSA encryption as a means of securing data. Recent announcements over the past ten years concerning the breaking of RSA encryption keys have raised doubts about the security of RSA encryption. After all, the scientists who came up with RSA initially claim ..."
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This paper examines the practical utility of RSA encryption as a means of securing data. Recent announcements over the past ten years concerning the breaking of RSA encryption keys have raised doubts about the security of RSA encryption. After all, the scientists who came up with RSA initially claimed that such keys would take millions of years to break. Our analysis of this topic is divided into two large headings: the history of Cryptography and RSA. The history of cryptography demonstrates the cryptography is always improving as a result of pressure by cryptanalyst techniques. Once a flaw in a technique is uncovered, the cryptography changes to accommodate the flaw and make itself more secure. RSA did not come from nothingness, but rather a series of cryptographic exploits that have evolved into the cryptography goliath that exists today. In examining, the ways that other techniques have failed in the past, we are also demonstrating the ways that RSA has improved upon those flaws. The second half of the paper analyzes RSA cryptography in depth both its algorithm and its implementations. RSA can be subverted and there are alternate cryptographic techniques, but ultimately RSA remains the most ideal form of cryptography to date and in the foreseeable future. Thesis: Throughout history, there has been a constant battle between the cryptographers that encrypt and the cryptanalyst that break the encryption. Recently, there have been a series of findings concerning flaws and security leaks in implementations of RSA encryption. Coupled with the latest news concerning the breaking of a higher numbered RSA encryption key, the credibility of RSA has been called into question. However, RSA 2 represents an extraordinarily secure encryption scheme that is not threatened by many forms of subversion. With careful attention, RSA still represents a nearly unbreakable cryptographic scheme that has come as a direct result centuries of cryptographic evolution. 1.