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A formula on linear complexity of highest coordinate sequences from maximal periodic sequences over Galois rings

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Progress in Natural Science:Materials International 2006年第9期16卷 998-1001页

作者： HU Lei and SUN Nigang (state key laboratory of information security, graduate School of chinese academy of sciences, beijing 100049, china) state key laboratory of information security Graduate School of Chinese Academy of Sciences Beijing 100049 China

Using a polynomial expression of the highest coordinate map, we deduce an exact formula on the linear complexity of the highest coordinate sequence derived from a maximal periodic sequence over an arbitrary Galois ring of characteristic p2 , where p is a prime. This generalizes the known result of Udaya and Siddiqi for the case that the Galois ring is Z4.

关键词： Galois ring highest coordinate sequence linear complexity.

Paillier's trapdoor function hides Θ(n) bits

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Science china(information sciences) 2011年第9期54卷 1827-1836页

作者： SU Dong & Lü KeWei state key laboratory of information security,graduate university of chinese academy of sciences,beijing 100049,china state key laboratory of information security Graduate University of Chinese Academy of Sciences Beijing China

In this paper,we re-examine the bit security of Paillier’s trapdoor *** show that given a random w=gcyN mod N2 ∈ZN2* the most significant bit of its class c is a hard-core predicate,under a standard assumption that is computing composite residuosity class is *** the simultaneous security,we prove that n number of the class c’s bits are simultaneously hard-core under the standard assumption,where n is the length of c.

关键词： Paillier’s trapdoor function hard-core predicate hard-core function simultaneous security most significant bit

CMQV+:An authenticated key exchange protocol from CMQV

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Science china(information sciences) 2012年第7期55卷 1666-1674页

作者： LI Hui 1,2 & WU ChuanKun 1 1 state key laboratory of information security,Institute of Software,chinese academy of sciences,beijing 100190,china 2 graduate university of chinese academy of sciences,beijing 100049,china state key laboratory of information security Institute of Software Chinese Academy of Sciences Beijing China graduate university of chinese academy of sciences Beijing China

Ustaoglu presents a secure and efficient key exchange protocol named CMQV,based on the design rationales of HMQV and *** with the latter two protocols,on one hand,CMQV achieves high performance of HMQV,and on the other,it is proven secure in eCK model as NAXOS ***,CMQV enjoys the security proof under gap Diffie-Hellman assumption as indicated by its *** this paper,we propose a variant of CMQV,called CMQV+,which is proven secure under a weaker assumption (*** Diffie-Hellman assumption) in eCK model with random oracles while maintaining the high-performance feature of CMQV as much as possible.

关键词： key exchange eCK model trapdoor-test technique provable security CDH assumption

A two-round honest-verifier zero-knowledge protocol

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Science china(information sciences) 2010年第5期53卷 954-963页

作者： LIU HanWu 1,2 & LIN DongDai 1 1 The state key laboratory of information security, Institute of Software, chinese academy of sciences, beijing 100190, china 2 graduate university of the chinese academy of sciences, beijing 100049, china The state key laboratory of information security Institute of Software Chinese Academy of Sciences graduate university of the chinese academy of sciences

Since the concept of zero-knowledge protocols was introduced, it has attracted a lot of attention and in turn showed significant effect on the development of cryptography, complexity theory and other areas. The round complexity of a zero-knowledge protocol is a very important efficiency consideration, and it is required to be as small as possible. Generally, it is desirable to have zero-knowledge protocols with constant numbers of rounds. Goldreich and Oren proved that only languages in BPP have one-round and two-round zero-knowledge protocols. Moreover, they also showed that only languages in BPP have one-round honest-verifier zero-knowledge protocols. The notion of honest-verifier zero-knowledge protocols is highly non-trivial and fascinating itself, and has many other uses. Thus, the problem as to whether there exist two-round honest-verifier zero-knowledge protocols becomes an important open problem. In this paper, we introduce a new simulation technique and present a two-round honest-verifier zero-knowledge protocol for any language in N P under a standard complexity assumption based on this technique.

关键词： proof system argument system zero-knowledge witness indistinguishability black-box one-way permutation commitment scheme zap

Analysis of a kind of quantum cryptographic schemes based on secret sharing

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Science china(Physics,Mechanics & Astronomy) 2009年第9期52卷 1313-1316页

作者： ZHANG XingLan1 & JI DongYao2 1 College of Computer Science and Technology, beijing university of Technology, beijing 100124, china 2.state key laboratory of information security, graduate university of chinese academy of sciences, beijing 100049, china College of Computer Science and Technology Beijing University of Technology Beijing China state key laboratory of information security Graduate University of Chinese Academy of Sciences Beijing China

Recently, Yang et al. proposed a kind of quantum cryptographic schemes based on secret sharing. The main idea is drawn from the case, where any n participants who share a secret K can co-operate as K does. This process can be applied to encryption, authentication, signature and so on. Unfortunately, since there is no identity authentication of the share's holder, these schemes inherit the limitation of secret sharing in practice. If some participants do not follow the protocol, the protocol would be a failure at last. Moreover, these schemes encounter another serious attack. Any two participants can co-operate to defeat the schemes by sending different shares to the parties unknown to the distributor of the secret K, such that these parties can execute the protocol as well. The attack proves that it is not enough for quantum cryptographic schemes that only the secret key is secure.

关键词： quantum identity authentication quantum secure direct communication quantum signature secret sharing

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Dynamic tree-based authenticated group key exchange protocol

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Science china(information sciences) 2010年第8期53卷 1591-1602页

作者： LI Hui 1,2 , WU ChuanKun 1 & TENG JiKai 1,2 1 state key laboratory of information security, Institute of Software, chinese academy of sciences, beijing 100190, china 2 graduate university of chinese academy of sciences, beijing 100049, china state key laboratory of information security Institute of Software Chinese Academy of Sciences graduate university of chinese academy of sciences

Authenticated group key exchange protocols allow a group of users over a public network to establish a shared secret key for the subsequent cryptographic goals. In this paper, we extend BD-II scheme into a dynamic setting, and propose a tree-based authenticated key exchange protocol which is more suitable for dynamic groups in such as ad hoc networks. Our protocol is proven secure in random-oracle model. Additionally, we analyze the costs of our protocols in both communication and computation terms, and compare its performance with three well-known protocols.

关键词： tree-based group key exchange dynamic provable security

On constant-round zero-knowledge proofs of knowledge for NP-relations

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Science china(information sciences) 2010年第4期53卷 788-799页

作者： LI HongDa1*, XU HaiXia1, LI Bao1 & FENG DengGuo2 1state key laboratory of information security, graduate university of chinese academy of sciences, beijing 100049, china 2state key laboratory of information security, Institute of Software of chinese academy of sciences, beijing 100080, china state key laboratory of information security Graduate University of Chinese Academy of Sciences

This paper considers the existence of constant-round zero-knowledge proofs of knowledge for NP under standard assumptions. By introducing a new interactive proof model, we construct a 3-round zero-knowledge proof of knowledge system for the NP-relation under the assumption that factoring is intractable. Our construction not only shows the existence of constant-round zero-knowledge proofs of knowledge, but also gives a positive answer to the open problem of the existence of 3-round zero-knowledge proofs for NP.

关键词： zero-knowledge proof proof of knowledge constant-round NP-relation

CBCR:CBC MAC with rotating transformations

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Science china(information sciences) 2011年第11期54卷 2247-2255页

作者： ZHANG LiTing 1,2,WU WenLing 1,ZHANG Lei 1 & WANG Peng 21 state key laboratory of information security,Institute of Software,chinese academy of sciences,beijing 100190,china 2 graduate university of chinese academy of sciences,beijing 100049,china state key laboratory of information security Institute of Software Chinese Academy of Sciences graduate university of chinese academy of sciences

Message authentication codes (MACs) are widely used to protect data integrity and data origin authentication in *** this paper,we propose a new block-cipher-based MAC algorithm,CBCR,with provable security for arbitrary-length *** adopts rotating operations in the end of cipherblock-chaining structure,and it appends fixed-length prefixes to all messages,which implies flexible usages in *** example,these fixed-length prefixes can be filled with some security parameters,message redundancies,*** also propose CBCR0,a special case of CBCR that sets its prefix to be an all-zero *** with CMAC,a recommended standard by the US National Institute of Standards and Technology (NIST),CBCR0 enjoys all the advantages that CMAC has,but requires less memory;so,in practical applications,CBCR0 behaves as well as CMAC does,and it is even more suitable for environments with limited memory resources,*** cards.

关键词： message authentication code cipher block chaining block cipher provable security

Round-optimal zero-knowledge proofs of knowledge for NP

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Science china(information sciences) 2012年第11期55卷 2473-2484页

作者： LI HongDa1,FENG DengGuo2,LI Bao1 & XUE HaiXia1 1state key Lab of information security,graduate university of chinese academy of sciences,beijing 100049,china 2state key Lab of information security,Institute of software of chinese academy of sciences,beijing 100080,china state key Lab of information security Graduate University of Chinese Academy of Sciences Beijing China state key Lab of information security Institute of software of Chinese Academy of Sciences Beijing China

It is well known that all the known black-box zero-knowledge proofs of knowledge for NP are *** there exit constant-round black-box zero-knowledge proofs of knowledge for all NP languages under certain standard assumptions is an open *** paper focuses on the problem and gives a positive answer by presenting two constructions of constant-round(black-box) zero-knowledge proofs of knowledge for the HC(hamiltonian cycle) *** the recent result of Katz,our second construction which relies on the existence of claw-free functions has optimal round complexity(5-round) assuming the polynomial hierarchy does not collapse.

关键词： zero-knowledge proofs proofs of knowledge black-box simulation constant-round