排序方式: 共有82条查询结果,搜索用时 171 毫秒
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近年来,伽罗瓦环上的序列理论成为人们研究的热点问题.有限域上的No序列是一类伪随机序列,它在序列密码中占具十分重要的角色.本文利用伽罗瓦环上的置换,构造了伽罗瓦环Z_(p~e)上的一类新的No序列,并且研究了其线性复杂度.研究的结果表明此类No序列具有相当大的线性复杂度. 相似文献
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本文给出了一类新的密钥流生成器一变系数反馈移位寄存器,得到了该密钥流生成器序列的几个重要的密码学性质,并在文中给出了严格的数学证明。 相似文献
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Zhong-hua Shen 《高校应用数学学报(英文版)》2008,23(3):371-376
In 2000, a remote user authentication scheme using smart cards was proposed and the masquerade attacks were proved successful on this scheme. Recently, Kumar has suggested the idea of check digits to overcome the above attacks with a new scheme that removes these threats well. In this paper it is pointed out that the weakness still exists in Kumar's scheme, and the intruder can login to the remote system through having some information. A new scheme which can overcome these attacks and appears more secure and efficient than Kumar's is presented. 相似文献
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相关攻击与相关免疫函数 总被引:8,自引:0,他引:8
本文首先介绍了如何采用DC攻击法对一类流密码体制进行相关攻击,从而说明在密码学中有必要研究相关免疫(CI)函数。在综述了域F2上相关免疫(CI)函数的研究进展的同时,给出了CI函数在一般有限域上的特性和构造,并进一步研究有限环Z/(m)时的情景,本文详尽描述了CI函数的五种充要条件。最后提出了几个值得研究的未解决的问题。 相似文献
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正形置换在密码学中有着广泛的应用,利用m-序列的"三项式特性",给出了一个构造n元正形置换的新方法,该方法既不同于已有的由n-2元构造n元正形置换,也不同于基于正交拉丁方的由n元构造n+1元正形置换的方法. 相似文献
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Cryptanalysis of Multiparty Quantum Secret Sharing of Quantum State Using Entangled States 下载免费PDF全文
Security of a quantum secret sharing of quantum state protocol proposed by Guo et al. [Chin. Phys. Lett. 25 (2008) 16] is reexamined. It is shown that an eavesdropper can obtain some of the transmitted secret information by monitoring the classical channel or the entire secret by intercepting the quantum states, and moreover, the eavesdropper can even maliciously replace the secret message with an arbitrary message without being detected. Finally, the deep reasons why an eavesdropper can attack this protocol are discussed and the modified protocol is presented to amend the security loopholes. 相似文献