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228
Secret Key Agreement by Public Discussion From Common Information
 IEEE Transactions on Information Theory
, 1993
"... . The problem of generating a shared secret key S by two parties knowing dependent random variables X and Y , respectively, but not sharing a secret key initially, is considered. An enemy who knows the random variable Z, jointly distributed with X and Y according to some probability distribution PX ..."
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Cited by 255 (18 self)
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. The problem of generating a shared secret key S by two parties knowing dependent random variables X and Y , respectively, but not sharing a secret key initially, is considered. An enemy who knows the random variable Z, jointly distributed with X and Y according to some probability distribution PXY Z , can also receive all messages exchanged by the two parties over a public channel. The goal of a protocol is that the enemy obtains at most a negligible amount of information about S. Upper bounds on H(S) as a function of PXY Z are presented. Lower bounds on the rate H(S)=N (as N !1) are derived for the case where X = [X 1 ; : : : ; XN ], Y = [Y 1 ; : : : ; YN ] and Z = [Z 1 ; : : : ; ZN ] result from N independent executions of a random experiment generating X i ; Y i and Z i , for i = 1; : : : ; N . In particular it is shown that such secret key agreement is possible for a scenario where all three parties receive the output of a binary symmetric source over independent binary symmetr...
Generalized Privacy Amplification
 IEEE Transactions on Information Theory
, 1995
"... This paper provides a general treatment of privacy amplification by public discussion, a concept introduced by Bennett, Brassard and Robert [1] for a special scenario. The results have applications to unconditionallysecure secretkey agreement protocols, quantum cryptography and to a nonasymptotic ..."
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Cited by 215 (18 self)
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This paper provides a general treatment of privacy amplification by public discussion, a concept introduced by Bennett, Brassard and Robert [1] for a special scenario. The results have applications to unconditionallysecure secretkey agreement protocols, quantum cryptography and to a nonasymptotic and constructive treatment of the secrecy capacity of wiretap and broadcast channels, even for a considerably strengthened definition of secrecy capacity. I. Introduction This paper is concerned with unconditionallysecure secretkey agreement by two communicating parties Alice and Bob who both know a random variable W, for instance a random nbit string, about which an eavesdropper Eve has incomplete information characterized by the random variable V jointly distributed with W according to PV W . This distribution may partially be under Eve's control. Alice and Bob know nothing about PV W , except that it satisfies a certain constraint. We present protocols by which Alice and Bob can us...
Modern cryptography, probabilistic proofs and pseudorandomness, volume 17 of Algorithms and Combinatorics
, 1999
"... all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that new copies bear this notice and the full citation on the first page. Abstracting with credit is permitted. IIPreface You can start by put ..."
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Cited by 128 (13 self)
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all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that new copies bear this notice and the full citation on the first page. Abstracting with credit is permitted. IIPreface You can start by putting the do not disturb sign. Cay, in Desert Hearts (1985). The interplay between randomness and computation is one of the most fascinating scientific phenomena uncovered in the last couple of decades. This interplay is at the heart of modern cryptography and plays a fundamental role in complexity theory at large. Specifically, the interplay of randomness and computation is pivotal to several intriguing notions of probabilistic proof systems and is the focal of the computational approach to randomness. This book provides an introduction to these three, somewhat interwoven domains (i.e., cryptography, proofs and randomness). Modern Cryptography. Whereas classical cryptography was confined to
Discrete memoryless interference and broadcast channels with confidential messages: secrecy rate regions
 IEEE Transactions on Information Theory
, 2008
"... Abstract — Discrete memoryless interference and broadcast channels in which independent confidential messages are sent to two receivers are considered. Confidential messages are transmitted to each receiver with perfect secrecy, as measured by the equivocation at the other receiver. In this paper, w ..."
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Cited by 80 (9 self)
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Abstract — Discrete memoryless interference and broadcast channels in which independent confidential messages are sent to two receivers are considered. Confidential messages are transmitted to each receiver with perfect secrecy, as measured by the equivocation at the other receiver. In this paper, we derive inner and outer bounds for the achievable rate regions for these two communication systems. I.
Secure communication over fading channels
 In Proc. Annu. Allerton Conf. Communication, Control and Computing
, 2006
"... The fading broadcast channel with confidential messages (BCC) is investigated, where a source node has common information for two receivers (receivers 1 and 2), and has confidential information intended only for receiver 1. The confidential information needs to be kept as secret as possible from rec ..."
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Cited by 70 (11 self)
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The fading broadcast channel with confidential messages (BCC) is investigated, where a source node has common information for two receivers (receivers 1 and 2), and has confidential information intended only for receiver 1. The confidential information needs to be kept as secret as possible from receiver 2. The broadcast channel from the source node to receivers 1 and 2 is corrupted by multiplicative fading gain coefficients in addition to additive Gaussian noise terms. The channel state information (CSI) is assumed to be known at both the transmitter and the receivers. The parallel BCC with independent subchannels is first studied, which serves as an informationtheoretic model for the fading BCC. The secrecy capacity region of the parallel BCC is established. This result is then specialized to give the secrecy capacity region of the parallel BCC with degraded subchannels. The secrecy capacity region is then established for the parallel Gaussian BCC, and the optimal source power allocations that achieve the boundary of the secrecy capacity region are derived. In particular, the secrecy capacity region is established for the basic Gaussian BCC. The secrecy capacity results are then
Gamal, “On the secrecy capacity of fading channels
 in Proc. IEEE Int. Symp. Information Theory (ISIT
"... We consider the secure transmission of information over an ergodic fading channel in the presence of an eavesdropper. Our eavesdropper can be viewed as the wireless counterpart of Wyner’s wiretapper. The secrecy capacity of such a system is characterized under the assumption of asymptotically long c ..."
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Cited by 69 (4 self)
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We consider the secure transmission of information over an ergodic fading channel in the presence of an eavesdropper. Our eavesdropper can be viewed as the wireless counterpart of Wyner’s wiretapper. The secrecy capacity of such a system is characterized under the assumption of asymptotically long coherence intervals. We first consider the full Channel State Information (CSI) case, where the transmitter has access to the channel gains of the legitimate receiver and the eavesdropper. The secrecy capacity under this full CSI assumption serves as an upper bound for the secrecy capacity when only the CSI of the legitimate receiver is known at the transmitter, which is characterized next. In each scenario, the perfect secrecy capacity is obtained along with the optimal power and rate allocation strategies. We then propose a lowcomplexity on/off power allocation strategy that achieves nearoptimal performance with only the main channel CSI. More specifically, this scheme is shown to be asymptotically optimal as the average SNR goes to infinity, and interestingly, is shown to attain the secrecy capacity under the full CSI assumption. Remarkably, our results reveal the positive impact of fading on the secrecy capacity and establish the critical role of rate adaptation, based on the main channel CSI, in facilitating secure communications over slow fading channels. 1
The relayeavesdropper channel: Cooperation for secrecy
 IEEE Trans. on Inf. Theory
, 2006
"... This paper establishes the utility of user cooperation in facilitating secure wireless communications. In particular, the fourterminal relayeavesdropper channel is introduced and an outerbound on the optimal rateequivocation region is derived. Several cooperation strategies are then devised and ..."
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Cited by 61 (4 self)
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This paper establishes the utility of user cooperation in facilitating secure wireless communications. In particular, the fourterminal relayeavesdropper channel is introduced and an outerbound on the optimal rateequivocation region is derived. Several cooperation strategies are then devised and the corresponding achievable rateequivocation region are characterized. Of particular interest is the novel NoiseForwarding (NF) strategy, where the relay node sends codewords independent of the source message to confuse the eavesdropper. This strategy is used to illustrate the deaf helper phenomenon, where the relay is able to facilitate secure communications while being totally ignorant of the transmitted messages. Furthermore, NF is shown to increase the secrecy capacity in the reversely degraded scenario, where the relay node fails to offer performance gains in the classical setting. The gain offered by the proposed cooperation strategies is then proved theoretically and validated numerically in the additive White Gaussian Noise (AWGN) channel. I.
Entropy Measures and Unconditional Security in Cryptography
, 1997
"... One of the most important properties of a cryptographic system is a proof of its security. In the present work, informationtheoretic methods are used for proving the security of unconditionally secure cryptosystems. The security of such systems does not depend on unproven intractability assumptions ..."
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Cited by 60 (3 self)
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One of the most important properties of a cryptographic system is a proof of its security. In the present work, informationtheoretic methods are used for proving the security of unconditionally secure cryptosystems. The security of such systems does not depend on unproven intractability assumptions. A survey of entropy measures and their applications in cryptography is presented. A new information measure, smooth entropy, is introduced to quantify the number of almost uniform random bits that can be extracted from a source by probabilistic algorithms. Smooth entropy unifies previous work on privacy amplification in cryptography and on entropy smoothing in theoretical computer science. It enables a systematic investigation of the spoiling knowledge proof technique to obtain lower bounds on smooth entropy. The R'enyi entropy of order at least 2 of a random variable is a lower bound for its smooth entropy, whereas an assumption about R'enyi entropy of order 1, which is equivalent to the ...
Informationtheoretic key agreement: From weak to strong secrecy for free
 Lecture Notes in Computer Science
, 2000
"... Abstract. One of the basic problems in cryptography is the generation of a common secret key between two parties, for instance in order to communicate privately. In this paper we consider informationtheoretically secure key agreement. Wyner and subsequently Csiszár and Körner described and analyzed ..."
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Cited by 54 (2 self)
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Abstract. One of the basic problems in cryptography is the generation of a common secret key between two parties, for instance in order to communicate privately. In this paper we consider informationtheoretically secure key agreement. Wyner and subsequently Csiszár and Körner described and analyzed settings for secretkey agreement based on noisy communication channels. Maurer as well as Ahlswede and Csiszár generalized these models to a scenario based on correlated randomness and public discussion. In all these settings, the secrecy capacity and the secretkey rate, respectively, have been defined as the maximal achievable rates at which a highlysecret key can be generated by the legitimate partners. However, the privacy requirements were too weak in all these definitions, requiring only the ratio between the adversary’s information and the length of the key to be negligible, but hence tolerating her to obtain a possibly substantial amount of information about the resulting key in an absolute sense. We give natural stronger definitions of secrecy capacity and secretkey rate, requiring that the adversary obtains virtually no information about the entire key. We show that not only secretkey agreement satisfying the strong secrecy condition is possible, but even that the achievable keygeneration rates are equal to the previous weak notions of secrecy capacity and secretkey rate. Hence the unsatisfactory old definitions can be completely replaced by the new ones. We prove these results by a generic reduction of strong to weak key agreement. The reduction makes use of extractors, which allow to keep the required amount of communication negligible as compared to the length of the resulting key.