Results 1 - 10
of
833
Chosen-Ciphertext Security from Identity-Based Encryption. Adv
- in Cryptology — Eurocrypt 2004, LNCS
, 2004
"... We propose simple and efficient CCA-secure public-key encryption schemes (i.e., schemes secure against adaptive chosen-ciphertext attacks) based on any identity-based encryption (IBE) scheme. Our constructions have ramifications of both theoretical and practical interest. First, our schemes give a n ..."
Abstract
-
Cited by 280 (13 self)
- Add to MetaCart
We propose simple and efficient CCA-secure public-key encryption schemes (i.e., schemes secure against adaptive chosen-ciphertext attacks) based on any identity-based encryption (IBE) scheme. Our constructions have ramifications of both theoretical and practical interest. First, our schemes give a new paradigm for achieving CCA-security; this paradigm avoids “proofs of well-formedness ” that have been shown to underlie previous constructions. Second, instantiating our construction using known IBE constructions we obtain CCA-secure encryption schemes whose performance is competitive with the most efficient CCA-secure schemes to date. Our techniques extend naturally to give an efficient method for securing also IBE schemes (even hierarchical ones) against adaptive chosen-ciphertext attacks. Coupled with previous work, this gives the first efficient constructions of CCA-secure IBE schemes. 1
Design and Analysis of Practical Public-Key Encryption Schemes Secure against Adaptive Chosen Ciphertext Attack
- SIAM Journal on Computing
, 2001
"... A new public key encryption scheme, along with several variants, is proposed and analyzed. The scheme and its variants are quite practical, and are proved secure against adaptive chosen ciphertext attack under standard intractability assumptions. These appear to be the first public-key encryption sc ..."
Abstract
-
Cited by 231 (11 self)
- Add to MetaCart
(Show Context)
A new public key encryption scheme, along with several variants, is proposed and analyzed. The scheme and its variants are quite practical, and are proved secure against adaptive chosen ciphertext attack under standard intractability assumptions. These appear to be the first public-key encryption schemes in the literature that are simultaneously practical and provably secure.
Fairplay — a secure two-party computation system
- In USENIX Security Symposium
, 2004
"... Advances in modern cryptography coupled with rapid growth in processing and communication speeds make secure twoparty computation a realistic paradigm. Yet, thus far, interest in this paradigm has remained mostly theoretical. This paper introduces Fairplay [28], a full-fledged system that implements ..."
Abstract
-
Cited by 229 (6 self)
- Add to MetaCart
Advances in modern cryptography coupled with rapid growth in processing and communication speeds make secure twoparty computation a realistic paradigm. Yet, thus far, interest in this paradigm has remained mostly theoretical. This paper introduces Fairplay [28], a full-fledged system that implements generic secure function evaluation (SFE). Fairplay comprises a high level procedural definition language called SFDL tailored to the SFE paradigm; a compiler of SFDL into a one-pass Boolean circuit presented in a language called SHDL; and Bob/Alice programs that evaluate the SHDL circuit in the manner suggested by Yao in [39]. This system enables us to present the first evaluation of an overall SFE in real settings, as well as examining its components and identifying potential bottlenecks. It provides a test-bed of ideas and enhancements concerning SFE, whether by replacing parts of it, or by integrating with it. We exemplify its utility by examining several alternative implementations of oblivious transfer within the system, and reporting on their effect on overall performance. 1
Concurrent Zero-Knowledge
- IN 30TH STOC
, 1999
"... Concurrent executions of a zero-knowledge protocol by a single prover (with one or more verifiers) may leak information and may not be zero-knowledge in toto. In this paper, we study the problem of maintaining zero-knowledge We introduce the notion of an (; ) timing constraint: for any two proces ..."
Abstract
-
Cited by 173 (18 self)
- Add to MetaCart
Concurrent executions of a zero-knowledge protocol by a single prover (with one or more verifiers) may leak information and may not be zero-knowledge in toto. In this paper, we study the problem of maintaining zero-knowledge We introduce the notion of an (; ) timing constraint: for any two processors P1 and P2 , if P1 measures elapsed time on its local clock and P2 measures elapsed time on its local clock, and P2 starts after P1 does, then P2 will finish after P1 does. We show that if the adversary is constrained by an (; ) assumption then there exist four-round almost concurrent zero-knowledge interactive proofs and perfect concurrent zero-knowledge arguments for every language in NP . We also address the more specific problem of Deniable Authentication, for which we propose several particularly efficient solutions. Deniable Authentication is of independent interest, even in the sequential case; our concurrent solutions yield sequential solutions without recourse to timing, i.e., in the standard model.
Universally Composable Commitments
, 2001
"... We propose a new security measure for commitment protocols, called Universally Composable ..."
Abstract
-
Cited by 170 (10 self)
- Add to MetaCart
(Show Context)
We propose a new security measure for commitment protocols, called Universally Composable
HMQV: A High-Performance Secure Diffie-Hellman Protocol
- Protocol, Advances in Cryptology — CRYPTO ’05, LNCS 3621
, 2005
"... The MQV protocol of Law, Menezes, Qu, Solinas and Vanstone is possibly the most e#cient of all known authenticated Di#e-Hellman protocols that use public-key authentication. In addition to great performance, the protocol has been designed to achieve a remarkable list of security properties. As a ..."
Abstract
-
Cited by 169 (6 self)
- Add to MetaCart
(Show Context)
The MQV protocol of Law, Menezes, Qu, Solinas and Vanstone is possibly the most e#cient of all known authenticated Di#e-Hellman protocols that use public-key authentication. In addition to great performance, the protocol has been designed to achieve a remarkable list of security properties. As a result MQV has been widely standardized, and has recently been chosen by the NSA as the key exchange mechanism underlying "the next generation cryptography to protect US government information".
Universally Composable Two-Party and Multi-Party Secure Computation
, 2002
"... We show how to securely realize any two-party and multi-party functionality in a universally composable way, regardless of the number of corrupted participants. That is, we consider an asynchronous multi-party network with open communication and an adversary that can adaptively corrupt as many pa ..."
Abstract
-
Cited by 151 (34 self)
- Add to MetaCart
(Show Context)
We show how to securely realize any two-party and multi-party functionality in a universally composable way, regardless of the number of corrupted participants. That is, we consider an asynchronous multi-party network with open communication and an adversary that can adaptively corrupt as many parties as it wishes. In this setting, our protocols allow any subset of the parties (with pairs of parties being a special case) to securely realize any desired functionality of their local inputs, and be guaranteed that security is preserved regardless of the activity in the rest of the network. This implies that security is preserved under concurrent composition of an unbounded number of protocol executions, it implies non-malleability with respect to arbitrary protocols, and more. Our constructions are in the common reference string model and rely on standard intractability assumptions.
On the security of joint signature and encryption
, 2002
"... We formally study the notion of a joint signature and encryption in the public-key setting. We refer to this primitive as signcryption, adapting the terminology of [35]. We present two definitions for the security of signcryption depending on whether the adversary is an outsider or a legal user of t ..."
Abstract
-
Cited by 150 (6 self)
- Add to MetaCart
(Show Context)
We formally study the notion of a joint signature and encryption in the public-key setting. We refer to this primitive as signcryption, adapting the terminology of [35]. We present two definitions for the security of signcryption depending on whether the adversary is an outsider or a legal user of the system. We then examine generic sequential composition methods of building signcryption from a signature and encryption scheme. Contrary to what recent results in the symmetric setting [5, 22] might lead one to expect, we show that classical “encrypt-then-sign” (EtS) and “sign-then-encrypt” (StE) methods are both secure composition methods in the public-key setting. We also present a new composition method which we call “commit-then-encrypt-and-sign” (CtE&S). Unlike the generic sequential composition methods, CtE&S applies the expensive signature and encryption operations in parallel, which could imply a gain in efficiency over the StE and EtS schemes. We also show that the new CtE&S method elegantly combines with the recent “hash-sign-switch” technique of [30], leading to efficient on-line/off-line signcryption. Finally and of independent interest, we discuss the definitional inadequacy of the standard notion of chosen ciphertext (CCA2) security. We suggest a natural and very slight relaxation of CCA2-security, which we call generalized CCA2-ecurity (gCCA2). We show that gCCA2-security suffices for all known uses of CCA2-secure encryption, while no longer suffering from the definitional shortcomings of the latter.
