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立方攻击是在2009年欧洲密码年会上由Dinur和Shamir提出的一种新型密码分析方法,该方法旨在寻找密钥比特之间的线性关系。CTC(Courtois Toy Cipher)是N.Courtois设计的一种用于密码分析研究的分组密码算法,该算法的密钥长度、明文长度和迭代轮数都是可变的。文中利用立方攻击方法针对密钥长度为60bit的4轮CTC进行了分析,在选择明文攻击条件下,结合二次测试可恢复全部密钥,密钥恢复阶段仅需要不到2~10次加密算法。 相似文献
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提出了一种新的PRESENT密码故障分析方法——代数故障攻击。将代数攻击和故障攻击相结合,首先利用代数攻击方法建立密码算法等效布尔代数方程组;然后通过故障攻击手段获取错误密文信息,并将故障差分和密文差分转化为额外的布尔代数方程组;最后使用CryptoMiniSAT解析器求解方程组恢复密钥。结果表明:在PRESENT-80的第29轮注入宽度为4的故障,故障位置和值未知时,2次故障注入可在50s内恢复64bit后期白化密钥,将PRESENT-80密钥搜索空间降低为216,经1min暴力破解恢复完整主密钥;和现有PRESENT故障攻击相比,该攻击所需样本量是最小的;此外该代数故障分析方法也可为其他分组密码故障分析提供一定思路。 相似文献
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对混沌序列密码的相关密钥攻击 总被引:9,自引:0,他引:9
该文首次提出了对混沌序列密码的相关密钥攻击方法。该方法将线性密码分析的思想与对混沌密码的分割攻击方法相结合, 利用多个相关密钥产生的乱数序列对混沌密码实施分割攻击, 从而大大提高了分割攻击方法的效率, 克服了当混沌密码吻合度分布泄漏的信息较小或密钥规模较大时, 分割攻击方法难以将攻击方案的计算复杂性降低在可实现范围内的局限。作为例子, 该文实现了对具有64bit密钥的ZLL混沌密码的相关密钥攻击, 在主频为2.5GHz的Pentium 4-PC机上, 整个攻击时间平均为154s, 成功率为0.96。 相似文献
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分析研究了CIKS-128分组密码算法在相关密钥-差分攻击下的安全性.利用DDP结构和非线性函数的差分信息泄漏规律构造了一条高概率相关密钥-差分特征,并给出攻击算法,恢复出了192bit密钥;在此基础上,对剩余64bit密钥进行穷举攻击,恢复出了算法的全部256bit密钥.攻击所需的计算复杂度为277次CIKS-128算法加密,数据复杂度为277个相关密钥-选择明文,存储复杂度为225.4字节存储空间.分析结果表明,CIKS-128算法在相关密钥-差分攻击条件下是不安全的. 相似文献
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对迭代型混沌密码的逆推压缩攻击 总被引:2,自引:1,他引:1
本文发现了迭代型混沌密码的一个新信息泄漏规律,即对每个时刻i,由乱数序列求出的混沌映射在该时刻的可能输(及可能密钥参数)全体都可用若干个区间的并集简单描述,且对多对一混沌映射而言,每个区间内都有等效解的概率很大,并随着时刻i的减小,区间的长度急剧缩短.基于该信息泄漏规律,本文提出了攻击迭代型混沌密码的一个新方法,即逆推压缩攻击方法.在一定的条件下,该攻击方法的成功率为1,且计算复杂性、存储复杂性和数据复杂性都是密钥规模的线性函数.本文对廖旎焕等人在2006年发表的混沌扩频序列密码算法在密钥规模为64比特时做了100例攻击实验,每例实验平均仅需011秒就可求出等效密钥,从而验证了逆推压缩攻击方法的有效性和正确性.与现有的攻击混沌密码的一般方法相比,本文提出的方法是首个复杂性为密钥长度线性量级的攻击方法. 相似文献
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Renauld等人提出的代数侧信道攻击是将代数攻击和侧信道攻击结合起来的一种对分组密码的攻击方法.目前的研究主要针对算法的8-bit实现平台,对于更大的如64-bit实现平台,未见文献讨论.为此,本文提出一种扩展的代数侧信道攻击,直接将侧信道信息表示为密钥的显式函数.相比于通常的代数侧信道攻击,所需泄露信息更少.作为应用,给出了对LBlock轻量级分组密码的扩展的代数侧信道攻击,结果如下:对于64-bit平台实现的LBlock,假设其1-3轮输出的Hamming重量可以准确获得,则利用35个已知明文,便可建立关于LBlock 80-bit主密钥的非线性方程组;在普通的PC机上,利用Magma数学软件v2.12-16求Groebner基,1分钟内可以求得80-bit主密钥.这是对LBlock的首个代数侧信道攻击,同时说明Renauld等人给出的对代数侧信道攻击的其中一个防范方法:"将实现方法从8-bit平台转移到更大的设备"是不够的. 相似文献
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Rijndael密码的逆序Square攻击 总被引:3,自引:0,他引:3
2000年10月Rijnael被选为高级加密标准(AES),目前对它最有效攻击仍是由设计者提出的Square攻击。Square攻击是利用密码Square特性提出的选择明文攻击,可以对六轮和六轮以下的Rijndael密码进行成功的攻击,攻击六轮Rijndael的所有密钥的计算量为2272+264,五轮密码的复杂度为3240+232。该文提出了逆序Square攻击算法,该算法是基于密码Square特性提出的选择密文攻击方法。它攻出六轮Rijndael密码的所有密钥的复杂度为272+256,五轮密码的复杂度为240+224。若改变密钥扩散准则中的圈循环顺序,五轮密码的逆序Square攻击复杂度由240降为232,六轮的攻击复杂度由272降为264。 相似文献
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Wim Aerts Eli Biham Dieter De Moitié Elke De Mulder Orr Dunkelman Sebastiaan Indesteege Nathan Keller Bart Preneel Guy A. E. Vandenbosch Ingrid Verbauwhede 《Journal of Cryptology》2012,25(1):136-157
KeeLoq is a lightweight block cipher with a 32-bit block size and a 64-bit key. Despite its short key size, it is used in
remote keyless entry systems and other wireless authentication applications. For example, there are indications that authentication
protocols based on KeeLoq are used, or were used by various car manufacturers in anti-theft mechanisms. This paper presents
a practical key recovery attack against KeeLoq that requires 216 known plaintexts and has a time complexity of 244.5 KeeLoq encryptions. It is based on the principle of slide attacks and a novel approach to meet-in-the-middle attacks. 相似文献
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Tsunoo Y. Saito T. Shigeri M. Kubo H. Minematsu K. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2005,51(12):4312-4319
LILI-128 is the stream cipher proposed as a candidate cipher for the New European Schemes for Signatures, Integrity, and Encryption (NESSIE) Project. Some methods of breaking it more efficiently than an exhaustive search for its secret key have been found already. The authors propose a new method, which uses shorter bit sequence to break LILI-128 successfully. An attack that can be made with less data can be a more practical threat. With only 2/sup 7/ bits of keystream, this method can break LILI-128 successfully. The efficiency of our attack depends on the memory size. For example, with 2/sup 99.1/ computations, our attack breaks LILI-128, if 2/sup 28.6/-bit memory is available. 相似文献
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Telex作为典型的路由器重定向型反监管系统给互联网监管者带来了新的挑战.为帮助用户逃避监管,Telex利用路由器而非终端主机将用户的网络通信重定向到被屏蔽的目标站点.从审查者角度分析了Telex系统的安全性,提出了2类利用主动攻击破坏用户隐私的新方法.第一类为DoS攻击,利用了Telex握手协议的安全漏洞,在破坏系统可用性的同时还可能检出用户是否在使用Telex代理.同时给出了弥补该漏洞的改进协议.第二类称为TCP分组旁路攻击,利用非对称路由或IP隧道技术令客户端的部分TCP分组绕过路由器直达掩护站点,然后通过观察上行数据流的重传反应判断用户是否在使用Telex代理.通过一系列原型系统实验验证了旁路攻击的可行性.TCP分组旁路攻击也适用于其他路由器重定向型反监管系统. 相似文献
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《Communications Letters, IEEE》2008,12(12):886-887
The Parameterized Improved Fast Encryption Algorithm for Multimedia (PIFEA-M) is a fast cipher recently proposed by Chefranov (IEEE communications letters, Vol. 12, No. 6, June 2008) to resist an implementation dependent differential attack on earlier versions of the cipher. In this paper we show that a similar differential style attack can still break PIFEA-M with a very low data and computational complexity. 相似文献
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Differential cryptanalysis of DES-like cryptosystems 总被引:50,自引:2,他引:48
The Data Encryption Standard (DES) is the best known and most widely used cryptosystem for civilian applications. It was developed at IBM and adopted by the National Bureau of Standards in the mid 1970s, and has successfully withstood all the attacks published so far in the open literature. In this paper we develop a new type of cryptanalytic attack which can break the reduced variant of DES with eight rounds in a few minutes on a personal computer and can break any reduced variant of DES (with up to 15 rounds) using less than 256 operations and chosen plaintexts. The new attack can be applied to a variety of DES-like substitution/permutation cryptosystems, and demonstrates the crucial role of the (unpublished) design rules. 相似文献
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Shujun Li Guanrong Chen Xuanqin Mou 《Circuits and Systems II: Express Briefs, IEEE Transactions on》2004,51(12):665-669
This paper presents a comprehensive analysis on the security of the Yi-Tan-Siew chaotic cipher. A differential chosen-plaintext attack and a differential chosen-ciphertext attack are suggested to break the sub-key K, under the assumption that the time stamp can be altered by the attacker, which is reasonable in such attacks. Also, some security problems about the sub-keys /spl alpha/ and /spl beta/ are clarified, from both theoretical and experimental points of view. Further analysis shows that the security of this cipher is independent of the use of the chaotic tent map, once the sub-key K is removed via the proposed suggested differential chosen-plaintext attack. 相似文献
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Okamoto cryptosystems have drawn attention for their properties of fast encryption and decryption. A probabilistic attack based on the L/sup 3/ algorithm was proposed by Vallee et al. (1988). Other attacks have also been proposed. In the letter, a very simple and fast attack with continued fractions is given, which can completely break the Okamoto cryptosystems.<> 相似文献