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140
Wireless Ad Hoc Networks
, 2002
"... A mobile ad hoc network is a relatively new term for an old technology  a network that does not rely on preexisting infrastructure. Roots of this technology could be traced back to the early 1970s with the DARPA PRNet and the SURAN projects. The new twitch is the application of this technology in ..."
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Cited by 985 (14 self)
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A mobile ad hoc network is a relatively new term for an old technology  a network that does not rely on preexisting infrastructure. Roots of this technology could be traced back to the early 1970s with the DARPA PRNet and the SURAN projects. The new twitch is the application of this technology in the nonmilitary communication environments. Additionally, the research community has also recently addressed some extended features of this technology, such as multicasting and security. Also numerous new solutions to the "old" problems of routing and medium access control have been proposed. This survey attempts to summarize the stateofthe art of the ad hoc networking technology in four areas: routing, medium access control, multicasting, and security. Where possible, comparison between the proposed protocols is also discussed.
Security and Composition of Multiparty Cryptographic Protocols
 JOURNAL OF CRYPTOLOGY
, 1998
"... We present general definitions of security for multiparty cryptographic protocols, with focus on the task of evaluating a probabilistic function of the parties' inputs. We show that, with respect to these definitions, security is preserved under a natural composition operation. The definiti ..."
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Cited by 452 (20 self)
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We present general definitions of security for multiparty cryptographic protocols, with focus on the task of evaluating a probabilistic function of the parties' inputs. We show that, with respect to these definitions, security is preserved under a natural composition operation. The definitions follow the general paradigm of known definitions; yet some substantial modifications and simplifications are introduced. The composition operation is the natural `subroutine substitution' operation, formalized by Micali and Rogaway. We consider several standard settings for multiparty protocols, including the cases of eavesdropping, Byzantine, nonadaptive and adaptive adversaries, as well as the informationtheoretic and the computational models. In particular, in the computational model we provide the first definition of security of protocols that is shown to be preserved under composition.
Efficient threshold signature, multisignature and blind signature schemes based on the GapDiffieHellmanGroup signature scheme
 PROCEEDINGS OF PKC 2003, VOLUME 2567 OF LNCS
, 2003
"... We propose a robust proactive threshold signature scheme, a multisignature scheme and a blind signature scheme which work in any Gap DiffieHellman (GDH) group (where the Computational DiffieHellman problem is hard but the Decisional DiffieHellman problem is easy). Our constructions are based on t ..."
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Cited by 182 (0 self)
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We propose a robust proactive threshold signature scheme, a multisignature scheme and a blind signature scheme which work in any Gap DiffieHellman (GDH) group (where the Computational DiffieHellman problem is hard but the Decisional DiffieHellman problem is easy). Our constructions are based on the recently proposed GDH signature scheme of Boneh et al. [8]. Due to the instrumental structure of GDH groups and of the base scheme, it turns out that most of our constructions are simpler, more efficient and have more useful properties than similar existing constructions. We support all the proposed schemes with proofs under the appropriate computational assumptions, using the corresponding notions of security.
COCA: A Secure Distributed Online Certification Authority
 ACM Transactions on Computer Systems
"... this article, is such an online CA ..."
Secure Distributed Key Generation for DiscreteLog Based Cryptosystems
, 1999
"... Abstract. Distributed key generation is a main component of threshold cryptosystems and distributed cryptographic computing in general. Solutions to the distributed generation of private keys for discretelog based cryptosystems have been known for several years and used in a variety of protocols an ..."
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Cited by 161 (4 self)
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Abstract. Distributed key generation is a main component of threshold cryptosystems and distributed cryptographic computing in general. Solutions to the distributed generation of private keys for discretelog based cryptosystems have been known for several years and used in a variety of protocols and in many research papers. However, these solutions fail to provide the full security required and claimed by these works. We show how an active attacker controlling a small number of parties can bias the values of the generated keys, thus violating basic correctness and secrecy requirements of a key generation protocol. In particular, our attacks point out to the places where the proofs of security fail. Based on these findings we designed a distributed key generation protocol which we present here together with a rigorous proof of security. Our solution, that achieves optimal resiliency, can be used as a dropin replacement for key generation modules as well as other components of threshold or proactive discretelog based cryptosystems.
Mix and Match: Secure Function Evaluation via Ciphertexts (Extended Abstract)
 In Proceedings of Asiacrypt00
, 2000
"... We introduce a novel approach to general secure multiparty computation that avoids the intensive use of verifiable secret sharing characterizing nearly all previous protocols in the literature. Instead, our scheme involves manipulation of ciphertexts for which the underlying private key is shared by ..."
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Cited by 98 (5 self)
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We introduce a novel approach to general secure multiparty computation that avoids the intensive use of verifiable secret sharing characterizing nearly all previous protocols in the literature. Instead, our scheme involves manipulation of ciphertexts for which the underlying private key is shared by participants in the computation. The benefits of this protocol include a high degree of conceptual and structural simplicity, low message complexity, and substantial flexibility with respect to input and output value formats. We refer to this new approach as mix and match. While the atomic operations in mix and match are logical operations, rather than full field operations as in previous approaches, the techniques we introduce are nonetheless highly practical for computations involving intensive bitwise manipulation. One application for which mix and match is particularly well suited is that of sealedbid auctions. Thus, as another contribution in this paper, we present a practical, mixandmatchbased auction protocol that is fully private and noninteractive and may be readily adapted to a wide range of auction strategies.
A Simplified Approach to Threshold and Proactive RSA
 In Proceedings of CRYPTO
"... We present a solution to both the robust threshold RSA and proactive RSA problems. Our solutions are conceptually simple, and allow for an easy design of the system. The signing key, in our solution, is shared at all times in additive form, which allows for simple signing and for a particularly ..."
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Cited by 91 (2 self)
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We present a solution to both the robust threshold RSA and proactive RSA problems. Our solutions are conceptually simple, and allow for an easy design of the system. The signing key, in our solution, is shared at all times in additive form, which allows for simple signing and for a particularly efficient and straightforward refreshing process for proactivization. The key size is (up to a very small constant) the size of the RSA modulus, and the protocol runs in constant time, even when faults occur, unlike previous protocols where either the size of the key has a linear blowup (at best) in the number of players or the run time of the protocol is linear in the number of faults. The protocol is optimal in its resilience as it can tolerate a minority of faulty players.
Robust and Efficient Sharing of RSA Functions
, 1996
"... We present two efficient protocols which implement robust threshold RSA signature schemes, where the power to sign is shared by N players such that any subset of more then T signers can collaborate to produce a valid RSA signature on any given message, but no subset of fewer than T corrupted players ..."
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Cited by 88 (12 self)
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We present two efficient protocols which implement robust threshold RSA signature schemes, where the power to sign is shared by N players such that any subset of more then T signers can collaborate to produce a valid RSA signature on any given message, but no subset of fewer than T corrupted players can forge a signature. Our protocols are robust in the sense that the correct signature is computed even if up to T players behave in arbitrarily malicious way during the signature protocol. This in particular includes the cases of players that refuse to participate or that generate incorrect partial signatures. Our protocols achieve fault tolerance T of N=2, which is optimal. Our protocols are also very efficient, as the computation performed by each player is comparable to the computation cost of a single RSA signature. Robust threshold signature schemes have very important applications, since they provide increased security and availability for a signing server (e.g. a certification auth...
Efficient and Generalized Group Signatures
, 1997
"... The concept of group signatures was introduced by Chaum et al. at Eurocrypt '91. It allows a member of a group to sign messages anonymously on behalf of the group. In case of a later dispute a designated group manager can revoke the anonymity and identify the originator of a signature. In t ..."
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Cited by 72 (6 self)
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The concept of group signatures was introduced by Chaum et al. at Eurocrypt '91. It allows a member of a group to sign messages anonymously on behalf of the group. In case of a later dispute a designated group manager can revoke the anonymity and identify the originator of a signature. In this paper we propose a new efficient group signature scheme. Furthermore we present a model and the first realization of generalized group signatures. Such a scheme allows to define coalitions of group members that are able to sign on the group's behalf.
Proactive security: Longterm protection against breakins
 CryptoBytes
, 1997
"... Dalit Naor y Proactive security provides a method for maintaining the overall security of a system, even when individual components are repeatedly broken into and controlled by an attacker. In particular it provides for automated recovery of the security of individual components, avoiding the use of ..."
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Cited by 61 (9 self)
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Dalit Naor y Proactive security provides a method for maintaining the overall security of a system, even when individual components are repeatedly broken into and controlled by an attacker. In particular it provides for automated recovery of the security of individual components, avoiding the use of expensive and inconvenient manual processes (unless perhaps when an ongoing attack is detected). The technique calls for the distribution of trust among several components (servers), together with periodic refreshments of the sensitive data held by the servers. This way, the proactive approach guarantees uninterrupted security as long as not too many servers are broken into at the same time. We describe the proactive approach and review some algorithms, implementations, and applications. We elaborate on two of the most important results: proactive signatures and proactive secure communication. Proactive signatures provide a solution for longlived secret keys, such as the key of a certi cation authority. Proactive secure communication ensures secrecy and authenticity ofcommunication, with automated refresh of the secret keys. 1