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8,503 results · page 304 of 355
Man Ho Au, Willy Susilo, Yi Mu
No abstract is available for this record.
Yao Zheng
A trusted small world Peer-to-Peer (P2P) model with role and reputation based access control policies (SW-R2P) was designed to combine the network topology and trust evaluation in P2P network.The model utilizes the zero knowledge interactive proof (ZKIP) scheme to authenticate the group information between peers without transferring any related data.The group information is used to cluster the peers to construct a small world topology.The Bayesian trust network is involved into the SW-R2P model to evaluate the multi-faceted trust of the peer and the group,which supporting the action protocols of peers and the long links between groups.Simulation shows that the SW-R2P model performs much better than the Chord and R2P models in the resources lookup,clustering coefficient and peer reputation error.The SW-R2P model integrates the advantages of small world topology,ZKIP scheme and Bayesian trust network,therefore implements a trustworthy,secure and efficient P2P network.
Masayuki Abe, Georg Fuchsbauer, Jens Groth, Kristiyan Haralambiev · 5 authors
No abstract is available for this record.
Essam Ghadafi, Nigel P. Smart, Bogdan Warinschi
No abstract is available for this record.
Hoeteck Wee
No abstract is available for this record.
Vipul Goyal, Yuval Ishai, Mohammad Mahmoody, Amit Sahai
Motivated by the question of basing cryptographic protocols on stateless tamper-proof hardware tokens, we revisit the question of unconditional two-prover zero-knowledge proofs for NP. We show that such protocols exist in the interactive PCP model of Kalai and Raz (ICALP ’08), where one of the provers is replaced by a PCP oracle. This strengthens the feasibility result of Ben-Or, Goldwasser, Kilian, and Wigderson (STOC ’88) which requires two stateful provers. In contrast to previous zero-knowledge PCPs of Kilian, Petrank, and Tardos (STOC ’97), in our protocol both the prover and the PCP oracle are efficient given an NP witness. Our main technical tool is a new primitive that we call interactive locking, an efficient realization of an unconditionally secure commitment scheme in the interactive PCP model. We implement interactive locking by adapting previous constructions of interactive hashing protocols to our setting, and also provide a direct construction which uses a minimal amount of interaction and improves over our interactive hashing based constructions. Finally, we apply the above results towards showing the feasibility of basing unconditional cryptography on stateless tamper-proof hardware tokens, and obtain the following results:
Yang Yang, Ya-tao, Cao, LüLin · 6 authors
In order to solve the issue that existing direct anonymous attestation (DAA) scheme can not operate effectively in different domains,based on the original DAA scheme,a novel direct anonymous attestation protocol used in multi domains environment is proposed and designed,in which,the certificate issuer located in outside of domain can be considered as a proxy server to issue the DAA certificate for valid member nodes directly.Our designed mechanism accords with present trusted computing group (TCG) international specification,and can solve the problems of practical authentication and privacy information protection between different trusted domains efficiently.Compared with present DAA scheme,in our protocol,the anonymity,unforgeability can be guaranteed,and the replay-attack also can be avoided.It has important referenced and practical application value in trusted computing field.
Dominique Unruh
We motivate, define and construct quantum proofs of knowledge, proofs of knowledge secure against quantum adversaries. Our constructions are based on a new quantum rewinding technique that allows us to extract witnesses in many classical proofs of knowledge. We give criteria under which a classical proof of knowledge is a quantum proof of knowledge. Combining our results with Watrous’ results on quantum zeroknowledge, we show that there are zero-knowledge quantum proofs of knowledge for all languages in NP.
Yehuda Lindell
In this note, we show the existence of constant-round computational zero-knowledge proofs of knowledge for all N P. The existence of constant-round zero-knowledge proofs was proven by Goldreich and Kahan (Journal of Cryptology, 1996), and the existence of constant-round zeroknowledge arguments of knowledge was proven by Feige and Shamir (CRYPTO 1989). Although it is widely believed that there exist constant-round zero-knowledge proofs of knowledge for all N P, to the best of our knowledge, no proof of this fact has been published. 1
Eleanor Birrell, Salil Vadhan
No abstract is available for this record.
Abdullah M. Jaafar, Azman Samsudin
A zero-knowledge proof of identity protocol is a special cryptographic algorithm for identity verification. The security of most of the zero-knowledge proof of identity protocols is based on complex mathematical algorithms and requires heavy computations for both parties involved, the proverb and the verifier. Thus, the two parties must depend on computing devices (computers) to perform these computations. Visual cryptography is a special kind of the cryptography that does not require one to know the cryptography and the corresponding complex mathematical computations. In this paper, we propose a new method of zero-knowledge proof of identity based on a non-expansion visual cryptography to overcome the disadvantage of complex computation in the current zero-knowledge proof of identity protocols, thus overcoming the dependence on computing devices.
Carmit Hazay, Yehuda Lindell
In this note, we provide a formal proof of the fact that any protocol that is a zero-knowledge proof of knowledge for a relation R is also a secure protocol for the zero-knowledge proof of knowledge functionality, where the latter is defined according to the standard framework of stand-alone secure computation. Although this is a well-known fact, to the best of our knowledge, no full proof of this has been published. 1
Steven Gordon, Hoeteck Wee, David Xiao, Arkady Yerukhimovich
No abstract is available for this record.
SÅ‚awomir Grzonkowski
No abstract is available for this record.
Jens Groth
No abstract is available for this record.
José Bacelar Almeida, Endre Bangerter, Manuel Barbosa, Stephan Krenn · 6 authors
Abstract. Zero-knowledge proofs of knowledge (ZK-PoK) are important building blocks for numerous cryptographic applications. Although ZK-PoK have very useful properties, their real world deployment is typically hindered by their significant complexity compared to other (noninteractive) crypto primitives. Moreover, their design and implementation is time-consuming and error-prone. We contribute to overcoming these challenges as follows: We present a comprehensive specification language and a certifying compiler for ZK-PoK protocols based on Σ-protocols and composition techniques known in literature. The compiler allows the fully automatic translation of an abstract description of a proof goal into an executable implementation. Moreover, the compiler overcomes various restrictions of previous approaches, e.g., it supports the important class of exponentiation homomorphisms with hidden-order co-domain, needed for privacy-preserving applications such as idemix. Finally, our compiler is certifying, in the sense that it automatically produces a formal proof of security (soundness) of the compiled protocol (currently covering special homomorphisms) using the Isabelle/HOL theorem prover.
Rafael Pass, Muthuramakrishnan Venkitasubramaniam
No abstract is available for this record.
Benoît Libert, Moti Yung
No abstract is available for this record.
Sarah Meiklejohn, C. Chris Erway, Alptekın Küpçü, Theodora Hinkle · 5 authors
In recent years, many advances have been made in cryptography, as well as in the performance of communication networks and processors. As a result, many advanced cryptographic protocols are now efficient enough to be considered practical, yet research in the area remains largely theoretical and little work has been done to use these protocols in practice, despite a wealth of potential applications. This paper introduces a simple description language, ZKPDL, and an interpreter for this language. ZKPDL implements non-interactive zero-knowledge proofs of knowledge, a primitive which has received much attention in recent years. Using our language, a single program may specify the computation required by both the prover and verifier of a zero-knowledge protocol, while our interpreter performs a number of optimizations to lower both computational and space overhead. Our motivating application for ZKPDL has been the efficient implementation of electronic cash. As such, we have used our language to develop a cryptographic library, Cashlib, that provides an interface for using e-cash and fair exchange protocols without requiring expert knowledge from the programmer. 1
Yu-Feng Chien, Wing-Kai Hon
No abstract is available for this record.
Huijia Lin, Rafael Pass, Wei-Lung Dustin Tseng, Muthuramakrishnan Venkitasubramaniam
No abstract is available for this record.
José Bacelar Almeida, Endre Bangerter, Manuel Barbosa, Stephan Krenn · 6 authors
No abstract is available for this record.
Jens Groth
No abstract is available for this record.
Chengming Qi, Shoumei Cui
A proxy signature scheme enables a proxy signer to sign messages on behalf of the original signer. In this paper we propose an efficient proxy signature scheme based on RSA signature scheme, which divides the document M into m blocks and adds some redundant bits to each message block. We also give a kind of algorithm of the zero-knowledge proof of proposed digital signature. This algorithm has characteristics which has little computation, high reliability, and easy to be realized. The proposed signature scheme satisfies the secure requirements and is efficient.