Related-key impossible boomerang cryptanalysis on LBlock

The related-key impossible boomerang cryptanalysis and the strength of the lightweight block cipher LBlock against this method were investigated.A new attack on 22-round LBlock was presented combining impossible boomerang attacks with related-key attacks.A 15-round related-key impossible boomerang distinguisher was constructed.Based on the new distinguisher,an attack on 22-round LBlock was mounted successfully by concatenating 3-round to the beginning and 4-round to the end.The attack on 22-round LBlock required data complexity of only 2^51.3plaintexts and computational complexity of about 2 ^71.5422-round encryptions.Compared with published cryptanalysis results on 22-round LBlock,proposed attack has great advantages on data and computational complexities.     

Related-key impossible boomerang cryptanalysis on TWINE

In order to evaluate the security of the lightweight block cipher TWINE,the method of related-key impossible boomerang cryptanalysis was applied and a related-key impossible boomerang distinguisher consisting of 16-round and 17-round paths was constructed.Based on this new distinguisher,an attack on 23-round TWINE was mounted successfully by concatenating 4-round to the beginning and 2-round for the 17-round path and 3-round for the 16-round path to the end respectively.The attack on 23-round TWINE required data complexity of only 2 ^62.05plaintexts and computational complexity of about 2 ^70.4923-round encryptions.Compared with published cryptanalysis results,the proposed attack has obvious advantages.     

Biclique cryptanalysis on lightweight block ciphers I-PRESENT-80 and I-PRESENT-128

I-PRESENT was a lightweight SPN block cipher for resource-constraint environments such as RFID tags and sensor networks.The biclique structures of I-PRESENT with sieve-in-the-middle technique was an constracted.The biclique cryptanalysis schemes on full-round I-PRESENT-80 and I-PRESENT-128 were proposed for the first time.The results show that the data complexity of the biclique cryptanalysis on I-PRESENT-80 and I-PRESENT-128 is 2 ²⁶ and 2³⁶ chosen ciphertexts respectively,and the time complexity on them is 2 ^79.48 and 2 ^127.33 encryptions respectively.The time and data complexity are better than that of the exhaustive attack.In addition,the time complexity on them can be reduced to 2 ^78.61 and 2^126.48 encryptions by using related-key technology of I-PRESENT.     

HIGHT算法的积分攻击

对轻量级分组密码算法HIGHT在积分攻击方法下的安全性进行了研究。首先纠正了现有研究成果在构造区分器时的不当之处,重新构造了HIGHT算法的11轮积分区分器,并构造了相应高阶积分扩展下的17轮区分器;其次利用所构造的17轮区分器,结合“时空折中”原理对25轮HIGHT算法进行了积分攻击;最后对攻击算法的复杂度进行了分析,攻击算法需要的数据复杂度为262.92,时间复杂度为266.20,空间复杂度为2119。分析结果表明,所给出的攻击算法的攻击轮数和时间复杂度要优于现有研究结果。     

对轻量级密码算法MIBS的相关密钥不可能差分攻击

研究了轻量级分组密码算法MIBS抵抗相关密钥不可能差分的能力。利用MIBS-80密钥编排算法的性质,给出了一个密钥差分特征,并结合特殊明密文对的选取,构造了一个10轮不可能差分。在此不可能差分特征上进行扩展,对14轮的MIBS-80进行了攻击,并给出了复杂度分析。此攻击的结果需要的数据复杂度为254和时间复杂度为256。     

Cryptanalysis of mCrypton—A lightweight block cipher for security of RFID tags and sensors

mCrypton is a 64‐bit lightweight block cipher designed for use in low‐cost and resource‐constrained applications such as RFID tags and sensors in wireless sensor networks. In this paper, we investigate the strength of this cipher against related‐key impossible differential cryptanalysis. First, we construct two 6‐round related‐key impossible differentials for mCrypton‐96 and mCrypton‐128. Then, using these distinguishers, we present 9‐round related‐key impossible differential attacks on these two versions. The attack on mCrypton‐96 requires 2^59.9 chosen plaintexts, and has a time complexity of about 2^74.9 encryptions. The data and time complexities for the attack on mCrypton‐128 are 2^59.7 chosen plaintexts and 2^66.7 encryptions, respectively. Copyright © 2011 John Wiley & Sons, Ltd.     

ARIA密码算法的不可能差分归一化分析

Unified Impossible Differential (UID) cryptanalysis is a systematic method for finding impossible differentials for block ciphers. Regarding to the problem of automatically retrieving the impossible differential characteristics of block ciphers, with the use of particular intermediate difference state expression, UID gets the same or better results compared with other present cryptanalysis results. ARIA is a Korean block cipher expecting that there are no impossible differentials on four or more rounds. Based on a property of the Diffusion Layer (DL) of ARIA, a specific selection is used before conflict searching to optimize. UID is applied to ARIA, and 6 721 impossible differential chains are found. The length of those chains is four rounds, the same as existing results, but more varied in form. Moreover, ARIA is a Substitution-Permutation Network (SPN), not a Feistel structure or generalized Feistel structure as UID was applied to before.     

Substitution-permutation networks resistant to differential and linear cryptanalysis

In this paper we examine a class of product ciphers referred to as substitution-permutation networks. We investigate the resistance of these cryptographic networks to two important attacks: differential cryptanalysis and linear cryptanalysis. In particular, we develop upper bounds on the differential characteristic probability and on the probability of a linear approximation as a function of the number of rounds of substitutions. Further, it is shown that using large S-boxes with good diffusion characteristics and replacing the permutation between rounds by an appropriate linear transformation is effective in improving the cipher security in relation to these two attacks.This work was supported by the Natural Sciences and Engineering Research Council of Canada and the Telecommunications Research Institute of Ontario, and was presented at the rump session of CRYPTO '93. Howard Heys is now with Electrical Engineering, Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John's, Newfoundland, Canada A1B 3X5.     

多重线性密码分析的改进

本文介绍一种有助于对分组密码作线性密码分析并能减少有效攻击所数据量的算法，给出了该算法成功率的计算公式，并与现有的线性密码分析方法作了比较。     

LBlock算法的相关密钥-不可能差分攻击

该文研究了LBlock分组密码算法在相关密钥-不可能差分条件下的安全性.利用子密钥生成算法的差分信息泄漏规律,构造了多条低重量子密钥差分链,给出了15轮相关密钥-不可能差分区分器.通过扩展区分器,给出了23轮和24轮LBlock算法的相关密钥-不可能差分攻击方法.攻击所需的数据复杂度分别为2^65.2和2^65.6个选择明文,计算复杂度分别为2^66.2次23轮LBlock算法加密和2^66.6次24轮LBlock算法加密,存储复杂度分别为2^61.2和2^77.2字节存储空间.与已有结果相比,首次将针对LBlock算法的攻击扩展到了23轮和24轮.     

高级加密标准AES候选之一--Twofish

介绍了AES的一个候选算法——Twofish,它是一个128位分组加密算法．该密码由一个16圈的Feistel网络构成．描述了Twofish的加解密过程及子密钥生成过程,同时对其性能和抗攻击能力作了分析．     

GRANULE和MANTRA算法的不可能差分区分器分析

轻量级分组密码算法GRANULE和MANTRA结构简单,加密速度快且易于软硬件实现,特别适用于资源受限环境.为对这2种算法进行安全性分析,提出一种不可能差分区分器的自动化搜索方法.基于GRANULE和MANTRA算法结构特性,通过分析其S盒的差分分布表得到S盒差分特征,再利用中间相遇思想,分别对从加/解密方向得到的差分...     

Cryptanalysis of mCrypton‐64

In recent years, because of the security requirements of resource‐constrained devices, design and analysis of lightweight block ciphers has received more attention. mCrypton is a lightweight block cipher that has been specifically designed for using in resource‐constrained devices, such as low‐cost radio‐frequency identification tags and sensors. In this paper, we consider cryptanalysis of full‐round mCrypton‐64 using a new extension of biclique attack called non‐isomorphic biclique cryptanalysis. As it is known, effectiveness of the biclique attack is highly dependent to the weakness of key schedule, and it does not seem to be appropriate for block ciphers with strong key scheduling. The non‐isomorphic biclique attack, using an asymmetric key partitioning technique, provides more degrees of freedom to the attacker and makes it possible to use the diffusion layer properties of a block cipher for constructing longer bicliques. Results show that the attack on full‐round mCrypton requires 2^33.9 chosen plaintexts and a time complexity of 2^62.67 encryptions. The computational complexity reduces to 2^62.3, 2^61.4, and 2^59.75 encryptions for 10, 8, and 6 rounds of mCrypton‐64, respectively. We also have a discussion on the general form of the computational complexity for non‐isomorphic biclique cryptanalysis. Copyright © 2014 John Wiley & Sons, Ltd.     

差分分析中的特征概率计算问题研究

该文指出了长期以来在差分密码分析中所采用的差分特征概率计算方法与差分分析基本原理不相符合的矛盾,对这一问题进行了深入研究,给出了二者等价的充分条件,力图解决差分分析方法的理论基础问题．     

分组密码的随机算法

讨论了分组密码随机算法的优点和实现问题,并描述了随机算法在CAST和SAFER+中的若干实现,分别称为随机盒、随机网络和随机群.它们以计算复杂度的少量增加换取了安全性的明显提高.     

LBlock 码的不可能差分密码性能分析

该文分析研究了LBlock分组密码算法的不可能差分性质.基于LBlock算法的轮函数结构和部分密钥分别猜测技术,给出了21轮和22轮的LBlock算法的不可能差分分析方法.攻击21轮LBlock算法所需的数据量约为262,计算量约为262次21轮加密;攻击22轮LBlock算法所需的数据量约为262.5,计算量约为263.5次22轮加密.与已有的结果相比较,分析所需的计算量均有明显的降低,是目前不可能差分分析攻击LBlock的最好结果.     

LiCi分组密码算法的不可能差分分析

LiCi是由Patil等人(2017)提出的轻量级分组密码算法。由于采用新型的设计理念,该算法具有结构紧凑、能耗低、占用芯片面积小等优点,特别适用于资源受限的环境。目前该算法的安全性备受关注,Patil等人声称：16轮简化算法足以抵抗经典的差分攻击及线性攻击。该文基于S盒的差分特征,结合中间相遇思想,构造了一个10轮的不可能差分区分器。基于此区分器,向前后各扩展3轮,并利用密钥编排方案,给出了LiCi的一个16轮的不可能差分分析方法。该攻击需要时间复杂度约为2^83.08次16轮加密,数据复杂度约为2^59.76选择明文,存储复杂度约为2^76.76数据块,这说明16轮简化的LiCi算法无法抵抗不可能差分攻击。     

一类高阶差分密码分析

对迭代型分组密码给出了新一类高阶差分,并对ＳＡＦＥＲ进行了高阶差分密码分析,分析结果表明,对ＳＡＦＥＲ进行二阶差分攻击的效率远高于一阶差分。     

PRESENT代数故障攻击的改进与评估

提出了一种基于代数分析的PRESENT故障攻击改进方法,将代数分析用于密码和故障方程构建,通过逆向构建加密方程来加快求解速度;提出了一种故障注入后的密钥剩余熵评估方法,可评估不同故障模型下的PRESENT抗故障攻击安全性;最后对智能卡上的8位智能卡上的PRESENT实现进行了时钟毛刺故障注入,最好情况下1次故障注入即可恢复主密钥,这是PRESENT故障攻击在数据复杂度上的最好结果。