Results 11  20
of
417
HAIL: A HighAvailability and Integrity Layer for Cloud Storage
, 2009
"... We introduce HAIL (HighAvailability and Integrity Layer), a distributed cryptographic system that permits a set of servers to prove to a client that a stored file is intact and retrievable. HAIL strengthens, formally unifies, and streamlines distinct approaches from the cryptographic and distribute ..."
Abstract

Cited by 194 (4 self)
 Add to MetaCart
(Show Context)
We introduce HAIL (HighAvailability and Integrity Layer), a distributed cryptographic system that permits a set of servers to prove to a client that a stored file is intact and retrievable. HAIL strengthens, formally unifies, and streamlines distinct approaches from the cryptographic and distributedsystems communities. Proofs in HAIL are efficiently computable by servers and highly compact— typically tens or hundreds of bytes, irrespective of file size. HAIL cryptographically verifies and reactively reallocates file shares. It is robust against an active, mobile adversary, i.e., one that may progressively corrupt the full set of servers. We propose a strong, formal adversarial model for HAIL, and rigorous analysis and parameter choices. We show how HAIL improves on the security and efficiency of existing tools, like Proofs of Retrievability (PORs) deployed on individual servers. We also report on a prototype implementation. 1
Universal Hash Proofs and a Paradigm for Adaptive Chosen Ciphertext Secure PublicKey Encryption
, 2001
"... We present several new and fairly practical publickey encryption schemes and prove them secure against adaptive chosen ciphertext attack. One scheme is based on Paillier's Decision Composite Residuosity (DCR) assumption [7], while another is based in the classical Quadratic Residuosity (QR) ..."
Abstract

Cited by 191 (7 self)
 Add to MetaCart
(Show Context)
We present several new and fairly practical publickey encryption schemes and prove them secure against adaptive chosen ciphertext attack. One scheme is based on Paillier's Decision Composite Residuosity (DCR) assumption [7], while another is based in the classical Quadratic Residuosity (QR) assumption. The analysis is in the standard cryptographic model, i.e., the security of our schemes does not rely on the Random Oracle model. We also introduce the notion of a universal hash proof system. Essentially, this is a special kind of noninteractive zeroknowledge proof system for an NP language. We do not show that universal hash proof systems exist for all NP languages, but we do show how to construct very efficient universal hash proof systems for a general class of grouptheoretic language membership problems. Given an ecient universal hash proof system for a language with certain natural cryptographic indistinguishability properties, we show how to construct an efficient publickey encryption schemes secure against adaptive chosen ciphertext attack in the standard model. Our construction only uses the universal hash proof system as a primitive: no other primitives are required, although even more efficient encryption schemes can be obtained by using hash functions with appropriate collisionresistance properties. We show how to construct efficient universal hash proof systems for languages related to the DCR and QR assumptions. From these we get corresponding publickey encryption schemes that are secure under these assumptions. We also show that the CramerShoup encryption scheme (which up until now was the only practical encryption scheme that could be proved secure against adaptive chosen ciphertext attack under a reasonable assumption, namely, the Decision...
Tracing Traitors
, 1994
"... We give cryptographic schemes that help trace the source of leaks when sensitive or proprietary data is made available to a large set of parties. A very relevant application is in the context of pay television, where only paying customers should be able to view certain programs. In this application ..."
Abstract

Cited by 171 (10 self)
 Add to MetaCart
We give cryptographic schemes that help trace the source of leaks when sensitive or proprietary data is made available to a large set of parties. A very relevant application is in the context of pay television, where only paying customers should be able to view certain programs. In this application the programs are normally encrypted and then the sensitive data is the decryption keys that are given to paying customers. If a pirate decoder is found it is desirable to reveal the source of its decryption keys. We describe fully resilient schemes which can be used against any decoder which decrypts with nonnegligible probability. Since there is typically little demand for decoders which decrypt only a small fraction of the transmissions (even if it is nonnegligible), we further introduce threshold tracing schemes which can only be used against decoders which succeed in decryption with probability greater than some threshold. Threshold schemes are considerably more efficient than fully resilient schemes.
SecretKey Reconciliation by Public Discussion
, 1994
"... . Assuming that Alice and Bob use a secret noisy channel (modelled by a binary symmetric channel) to send a key, reconciliation is the process of correcting errors between Alice's and Bob's version of the key. This is done by public discussion, which leaks some information about the secret ..."
Abstract

Cited by 161 (3 self)
 Add to MetaCart
. Assuming that Alice and Bob use a secret noisy channel (modelled by a binary symmetric channel) to send a key, reconciliation is the process of correcting errors between Alice's and Bob's version of the key. This is done by public discussion, which leaks some information about the secret key to an eavesdropper. We show how to construct protocols that leak a minimum amount of information. However this construction cannot be implemented efficiently. If Alice and Bob are willing to reveal an arbitrarily small amount of additional information (beyond the minimum) then they can implement polynomialtime protocols. We also present a more efficient protocol, which leaks an amount of information acceptably close to the minimum possible for sufficiently reliable secret channels (those with probability of any symbol being transmitted incorrectly as large as 15%). This work improves on earlier reconciliation approaches [R, BBR, BBBSS]. 1 Introduction Unlike public key cryptosystems, the securi...
Sketchbased Change Detection: Methods, Evaluation, and Applications
 IN INTERNET MEASUREMENT CONFERENCE
, 2003
"... Traffic anomalies such as failures and attacks are commonplace in today's network, and identifying them rapidly and accurately is critical for large network operators. The detection typically treats the traffic as a collection of flows that need to be examined for significant changes in traffic ..."
Abstract

Cited by 161 (17 self)
 Add to MetaCart
Traffic anomalies such as failures and attacks are commonplace in today's network, and identifying them rapidly and accurately is critical for large network operators. The detection typically treats the traffic as a collection of flows that need to be examined for significant changes in traffic pattern (e.g., volume, number of connections) . However, as link speeds and the number of flows increase, keeping perflow state is either too expensive or too slow. We propose building compact summaries of the traffic data using the notion of sketches. We have designed a variant of the sketch data structure, kary sketch, which uses a constant, small amount of memory, and has constant perrecord update and reconstruction cost. Its linearity property enables us to summarize traffic at various levels. We then implement a variety of time series forecast models (ARIMA, HoltWinters, etc.) on top of such summaries and detect significant changes by looking for flows with large forecast errors. We also present heuristics for automatically configuring the model parameters. Using a
Wireless informationtheoretic security  part I: Theoretical aspects
 IEEE Trans. on Information Theory
, 2006
"... In this twopart paper, we consider the transmission of confidential data over wireless wiretap channels. The first part presents an informationtheoretic problem formulation in which two legitimate partners communicate over a quasistatic fading channel and an eavesdropper observes their transmissi ..."
Abstract

Cited by 155 (12 self)
 Add to MetaCart
(Show Context)
In this twopart paper, we consider the transmission of confidential data over wireless wiretap channels. The first part presents an informationtheoretic problem formulation in which two legitimate partners communicate over a quasistatic fading channel and an eavesdropper observes their transmissions through another independent quasistatic fading channel. We define the secrecy capacity in terms of outage probability and provide a complete characterization of the maximum transmission rate at which the eavesdropper is unable to decode any information. In sharp contrast with known results for Gaussian wiretap channels (without feedback), our contribution shows that in the presence of fading informationtheoretic security is achievable even when the eavesdropper has a better average signaltonoise ratio (SNR) than the legitimate receiver — fading thus turns out to be a friend and not a foe. The issue of imperfect channel state information is also addressed. Practical schemes for wireless informationtheoretic security are presented in Part II, which in some cases comes close to the secrecy capacity limits given in this paper.
Efficient generation of shared RSA keys
 Advances in Cryptology  CRYPTO 97
, 1997
"... We describe efficient techniques for a number of parties to jointly generate an RSA key. At the end of the protocol an RSA modulus N = pq is publicly known. None of the parties know the factorization of N. In addition a public encryption exponent is publicly known and each party holds a share of the ..."
Abstract

Cited by 151 (5 self)
 Add to MetaCart
We describe efficient techniques for a number of parties to jointly generate an RSA key. At the end of the protocol an RSA modulus N = pq is publicly known. None of the parties know the factorization of N. In addition a public encryption exponent is publicly known and each party holds a share of the private exponent that enables threshold decryption. Our protocols are efficient in computation and communication. All results are presented in the honest but curious settings (passive adversary).
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 ..."
Abstract

Cited by 131 (13 self)
 Add to MetaCart
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
Lossy Trapdoor Functions and Their Applications
 ELECTRONIC COLLOQUIUM ON COMPUTATIONAL COMPLEXITY, REPORT NO. 80 (2007)
, 2007
"... We propose a new general primitive called lossy trapdoor functions (lossy TDFs), and realize it under a variety of different number theoretic assumptions, including hardness of the decisional DiffieHellman (DDH) problem and the worstcase hardness of standard lattice problems. Using lossy TDFs, we ..."
Abstract

Cited by 125 (21 self)
 Add to MetaCart
(Show Context)
We propose a new general primitive called lossy trapdoor functions (lossy TDFs), and realize it under a variety of different number theoretic assumptions, including hardness of the decisional DiffieHellman (DDH) problem and the worstcase hardness of standard lattice problems. Using lossy TDFs, we develop a new approach for constructing many important cryptographic primitives, including standard trapdoor functions, CCAsecure cryptosystems, collisionresistant hash functions, and more. All of our constructions are simple, efficient, and blackbox. Taken all together, these results resolve some longstanding open problems in cryptography. They give the first known (injective) trapdoor functions based on problems not directly related to integer factorization, and provide the first known CCAsecure cryptosystem based solely on worstcase lattice assumptions.