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IdentityBased Encryption from the Weil Pairing
, 2001
"... We propose a fully functional identitybased encryption scheme (IBE). The scheme has chosen ciphertext security in the random oracle model assuming an elliptic curve variant of the computational DiffieHellman problem. Our system is based on bilinear maps between groups. The Weil pairing on elliptic ..."
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Cited by 1699 (29 self)
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We propose a fully functional identitybased encryption scheme (IBE). The scheme has chosen ciphertext security in the random oracle model assuming an elliptic curve variant of the computational DiffieHellman problem. Our system is based on bilinear maps between groups. The Weil pairing on elliptic curves is an example of such a map. We give precise definitions for secure identity based encryption schemes and give several applications for such systems.
Practical Byzantine Fault Tolerance
"... This paper describes a new replication algorithm that is able to tolerate Byzantine faults. We believe that Byzantinefaulttolerant algorithms will be increasingly important in the future because malicious attacks and software errors are increasingly common and can cause faulty nodes to exhibit arbi ..."
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Cited by 682 (22 self)
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This paper describes a new replication algorithm that is able to tolerate Byzantine faults. We believe that Byzantinefaulttolerant algorithms will be increasingly important in the future because malicious attacks and software errors are increasingly common and can cause faulty nodes to exhibit arbitrary behavior. Whereas previous algorithms assumed a synchronous system or were too slow to be used in practice, the algorithm described in this paper is practical: it works in asynchronous environments like the Internet and incorporates several important optimizations that improve the response time of previous algorithms by more than an order of magnitude. We implemented a Byzantinefaulttolerant NFS service using our algorithm and measured its performance. The results show that our service is only 3 % slower than a standard unreplicated NFS.
Efficient dispersal of information for security, load balancing, and fault tolerance
 Journal of the ACM
, 1989
"... Abstract. An Information Dispersal Algorithm (IDA) is developed that breaks a file F of length L = ( F ( into n pieces F,, 1 5 i 5 n, each of length ( F, 1 = L/m, so that every m pieces suffice for reconstructing F. Dispersal and reconstruction are computationally efficient. The sum of the lengths ..."
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Cited by 561 (1 self)
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Abstract. An Information Dispersal Algorithm (IDA) is developed that breaks a file F of length L = ( F ( into n pieces F,, 1 5 i 5 n, each of length ( F, 1 = L/m, so that every m pieces suffice for reconstructing F. Dispersal and reconstruction are computationally efficient. The sum of the lengths ( F, 1 is (n/m). L. Since n/m can be chosen to be close to I, the IDA is space eflicient. IDA has numerous applications to secure and reliable storage of information in computer networks and even on single disks, to faulttolerant and efficient transmission of information in networks, and to communications between processors in parallel computers. For the latter problem provably timeefftcient and highly faulttolerant routing on the ncube is achieved, using just constant size buffers. Categories and Subject Descriptors: E.4 [Coding and Information Theory]: nonsecret encoding schemes
Small Byzantine Quorum Systems
 DISTRIBUTED COMPUTING
, 2001
"... In this paper we present two protocols for asynchronous Byzantine Quorum Systems (BQS) built on top of reliable channelsone for selfverifying data and the other for any data. Our protocols tolerate Byzantine failures with fewer servers than existing solutions by eliminating nonessential work in ..."
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Cited by 483 (49 self)
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In this paper we present two protocols for asynchronous Byzantine Quorum Systems (BQS) built on top of reliable channelsone for selfverifying data and the other for any data. Our protocols tolerate Byzantine failures with fewer servers than existing solutions by eliminating nonessential work in the write protocol and by using read and write quorums of different sizes. Since engineering a reliable network layer on an unreliable network is difficult, two other possibilities must be explored. The first is to strengthen the model by allowing synchronous networks that use timeouts to identify failed links or machines. We consider running synchronous and asynchronous Byzantine Quorum protocols over synchronous networks and conclude that, surprisingly, "selftiming" asynchronous Byzantine protocols may offer significant advantages for many synchronous networks when network timeouts are long. We show how to extend an existing Byzantine Quorum protocol to eliminate its dependency on reliable networking and to handle message loss and retransmission explicitly.
Attributebased encryption for finegrained access control of encrypted data
 In Proc. of ACMCCS’06
, 2006
"... As more sensitive data is shared and stored by thirdparty sites on the Internet, there will be a need to encrypt data stored at these sites. One drawback of encrypting data, is that it can be selectively shared only at a coarsegrained level (i.e., giving another party your private key). We develop ..."
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Cited by 481 (23 self)
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As more sensitive data is shared and stored by thirdparty sites on the Internet, there will be a need to encrypt data stored at these sites. One drawback of encrypting data, is that it can be selectively shared only at a coarsegrained level (i.e., giving another party your private key). We develop a new cryptosystem for finegrained sharing of encrypted data that we call KeyPolicy AttributeBased Encryption (KPABE). In our cryptosystem, ciphertexts are labeled with sets of attributes and private keys are associated with access structures that control which ciphertexts a user is able to decrypt. We demonstrate the applicability of our construction to sharing of auditlog information and broadcast encryption. Our construction supports delegation of private keys which subsumes Hierarchical IdentityBased Encryption (HIBE). E.3 [Data En
Ciphertextpolicy attributebased encryption
 In Proceedings of the IEEE Symposium on Security and Privacy (To Appear
, 2007
"... ..."
A survey of peertopeer content distribution technologies
 ACM Computing Surveys
, 2004
"... Distributed computer architectures labeled “peertopeer ” are designed for the sharing of computer resources (content, storage, CPU cycles) by direct exchange, rather than requiring the intermediation or support of a centralized server or authority. Peertopeer architectures are characterized by t ..."
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Cited by 369 (7 self)
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Distributed computer architectures labeled “peertopeer ” are designed for the sharing of computer resources (content, storage, CPU cycles) by direct exchange, rather than requiring the intermediation or support of a centralized server or authority. Peertopeer architectures are characterized by their ability to adapt to failures and accommodate transient populations of nodes while maintaining acceptable connectivity and performance. Content distribution is an important peertopeer application on the Internet that has received considerable research attention. Content distribution applications typically allow personal computers to function in a coordinated manner as a distributed storage medium by contributing, searching, and obtaining digital content. In this survey, we propose a framework for analyzing peertopeer content distribution technologies. Our approach focuses on nonfunctional characteristics such as security, scalability, performance, fairness, and resource management potential, and examines the way in which these characteristics are reflected in—and affected by—the architectural design decisions adopted by current peertopeer systems. We study current peertopeer systems and infrastructure technologies in terms of their distributed object location and routing mechanisms, their approach to content replication, caching and migration, their support for encryption, access control, authentication and identity, anonymity, deniability, accountability and reputation, and their use of resource trading and management schemes.
Fuzzy identitybased encryption
 In EUROCRYPT
, 2005
"... We introduce a new type of IdentityBased Encryption (IBE) scheme that we call Fuzzy IdentityBased Encryption. In Fuzzy IBE we view an identity as set of descriptive attributes. A Fuzzy IBE scheme allows for a private key for an identity, ω, to decrypt a ciphertext encrypted with an identity, ω ′ , ..."
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Cited by 354 (20 self)
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We introduce a new type of IdentityBased Encryption (IBE) scheme that we call Fuzzy IdentityBased Encryption. In Fuzzy IBE we view an identity as set of descriptive attributes. A Fuzzy IBE scheme allows for a private key for an identity, ω, to decrypt a ciphertext encrypted with an identity, ω ′ , if and only if the identities ω and ω ′ are close to each other as measured by the “set overlap ” distance metric. A Fuzzy IBE scheme can be applied to enable encryption using biometric inputs as identities; the errortolerance property of a Fuzzy IBE scheme is precisely what allows for the use of biometric identities, which inherently will have some noise each time they are sampled. Additionally, we show that FuzzyIBE can be used for a type of application that we term “attributebased encryption”. In this paper we present two constructions of Fuzzy IBE schemes. Our constructions can be viewed as an IdentityBased Encryption of a message under several attributes that compose a (fuzzy) identity. Our IBE schemes are both errortolerant and secure against collusion attacks. Additionally, our basic construction does not use random oracles. We prove the security of our schemes under the SelectiveID security model. 1
Proofs of partial knowledge and simplified design of witness hiding protocols
, 1994
"... Suppose we are given a proof of knowledge P in which a prover demonstrates that he knows a solution to a given problem instance. Suppose also that we have a secret sharing scheme S on n participants. Then under certain assumptions on P and S, we show how to transform P into a witness indistinguishab ..."
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Cited by 339 (14 self)
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Suppose we are given a proof of knowledge P in which a prover demonstrates that he knows a solution to a given problem instance. Suppose also that we have a secret sharing scheme S on n participants. Then under certain assumptions on P and S, we show how to transform P into a witness indistinguishable protocol, in which the prover demonstrates knowledge of the solution to a subset of n problem instances corresponding to a qualified set of participants. For example, using a threshold scheme, the prover can show that he knows at least d out of n solutions without revealing which d instances are involved. If the instances are independently generated, this can lead to witness hiding protocols, even if P did not have this property. Our transformation produces a protocol with the same number of rounds as P and communication complexity n times that of P. Our results use no unproven complexity assumptions.
Aggregate and Verifiably Encrypted Signatures from Bilinear Maps
, 2002
"... An aggregate signature scheme is a digital signature that supports aggregation: Given n signatures on n distinct messages from n distinct users, it is possible to aggregate all these signatures into a single short signature. This single signature (and the n original messages) will convince the verif ..."
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Cited by 321 (13 self)
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An aggregate signature scheme is a digital signature that supports aggregation: Given n signatures on n distinct messages from n distinct users, it is possible to aggregate all these signatures into a single short signature. This single signature (and the n original messages) will convince the verifier that the n users did indeed sign the n original messages (i.e., user i signed message M i for i = 1; : : : ; n). In this paper we introduce the concept of an aggregate signature scheme, present security models for such signatures, and give several applications for aggregate signatures. We construct an efficient aggregate signature from a recent short signature scheme based on bilinear maps due to Boneh, Lynn, and Shacham. Aggregate signatures are useful for reducing the size of certificate chains (by aggregating all signatures in the chain) and for reducing message size in secure routing protocols such as SBGP. We also show that aggregate signatures give rise to verifiably encrypted signatures. Such signatures enable the verifier to test that a given ciphertext C is the encryption of a signature on a given message M . Verifiably encrypted signatures are used in contractsigning protocols. Finally, we show that similar ideas can be used to extend the short signature scheme to give simple ring signatures.