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Hash(杂凑)函数是密码学的一个重要分支,广泛应用于消息认证、数据完整性、数字签名等领域。但是随着密码技术的不断发展,特别是王小云教授在2005年美密会上公布了MD5、SHA-1的碰撞实例,证明MD5和SHA-1不安全的。2010年中国国家密码管理局公布了中国商用密码杂凑算法标准-SM3密码杂凑算法,广泛应用于电子认证服务系统。用MATLAB编写出SM3算法程序,并用GUI设计算法界面,界面对于任何输入消息均产生一个杂凑值,并计算所耗时间。实验表明本算法速度快且准确。最后对SM3算法主要攻击方法做了归纳并得出结论:目前SM3算法是安全的。 相似文献
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基于椭圆曲线密码系统的优势,设计了一种群签名方案.方案从群签名的初始化、签名过程和验证进行了详细的研究和设计,并且使用了目前最新的杂凑函数SHA-3,增强了签名的安全性.最后分析了该方案的特性,与以基于RSA等通用签名算法进行比较,该方案在效率和安全性方面具有较好的性能. 相似文献
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一种基于FPGA的可重构密码芯片的设计与实现 总被引:1,自引:0,他引:1
介绍了SHA-1、SHA224及SHA256三种安全杂凑算法的基本流程,采用可重构体系结构的设计思想和方法设计出一款可实现这三种算法的可重构密码芯片,并对关键路径进行了优化设计。最后给出了基于Altera公司的Cyclone系列FPGA的可重构密码芯片的实现结果。 相似文献
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一种基于分组密码的hash函数的安全性分析及构造 总被引:1,自引:0,他引:1
利用已有的分组密码构造hash函数是一种非常方便的构造方法.早在1993 年Preneel 等人就对使用分组密码构造的64种hash 函数进行了安全分类,这些hash函数统称为PGV体制,它们都是单倍分组长度的,即输出长度和分组长度相同.2002 年Black在他的论文中对这64 种hash函数的安全性进行了严格的证明,证明其中的20种是安全的,其他是不安全的.随着计算技术的发展,人们感到单倍分组长度的hash函数的安全性不足,于是一些双倍分组长度的基于分组密码的hash函数被提了出来.但是其中的很多是不安全的.在AsiaCrypt2006上,一种使用了5个分组密码的双倍分组长度的hash函数被提了出来.作者声明这种构造方式是安全的,但没有给出安全性证明.本文对该体制进行了分析,发现其安全性并不理想,并针对本文的攻击提出了一种新的基于分组密码的hash函数,同时和SHA-256等hash函数的性能进行了对比. 相似文献
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Keccak杂凑函数是通过SHA-3最后一轮筛选的五个杂凑函数之一。通过对Keccak杂凑函数的非线性环节进行研究,提出了n元Keccak类非线性变换,并逐比特分析了其变换规律,通过分类研究,给出了两个原象不相等时,象不相等的充分条件和象相等的必要条件;进一步证明了当n为奇数时,n元Keccak类非线性变换是一个置换;当n为偶数时,不是一个置换。最后,证明了当n为奇数时,n元Keccak类非线性变换不是全向置换、全距置换和正形置换,为进一步应用这类编码模型奠定了理论基础。 相似文献
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一种基于多模式加密算法的文件保护方案* 总被引:1,自引:1,他引:0
结合对称密码算法中的DES、IDEA、AES和单向散列算法中的MD5、SHA-1、SHA-256等算法,提出了一种在同一文件内部采用多模式加密的方案,该方案比传统的单一模式加密的方案能更好地保证数据的完整性和安全性.详细描述了该方案的算法实现,通过试验验证了其实用性,同时分析了该方案的优点和不足. 相似文献
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Successful attacks against the two most commonly used cryptographic hash functions, MD5 and SHA-1, have triggered a kind of feeding frenzy in the cryptographic community. Many researchers are now working on hash function attacks, and we can expect new results in this area for the next several years. This article discusses the SHA-1 attack and the US National Institute of Standards and Technology's (NIST's) plans for SHA-1 and hash functions in general. 相似文献
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Michail Harris Kakarountas Athanasios Milidonis Athanasios Goutis Costas 《Dependable and Secure Computing, IEEE Transactions on》2009,6(4):255-268
Many cryptographic primitives that are used in cryptographic schemes and security protocols such as SET, PKI, IPSec, and VPNs utilize hash functions, which form a special family of cryptographic algorithms. Applications that use these security schemes are becoming very popular as time goes by and this means that some of these applications call for higher throughput either due to their rapid acceptance by the market or due to their nature. In this work, a new methodology is presented for achieving high operating frequency and throughput for the implementations of all widely used—and those expected to be used in the near future—hash functions such as MD-5, SHA-1, RIPEMD (all versions), SHA-256, SHA-384, SHA-512, and so forth. In the proposed methodology, five different techniques have been developed and combined with the finest way so as to achieve the maximum performance. Compared to conventional pipelined implementations of hash functions (in FPGAs), the proposed methodology can lead even to a 160 percent throughput increase. 相似文献
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Many cryptographic primitives that are used in cryptographic schemes and security protocols such as SET, PKI, IPSec and VPN's utilize hash functions - a special family of cryptographic algorithms. Hardware implementations of cryptographic hash functions provide high performance and increased security. However, potential faults during their normal operation cause significant problems in the authentication procedure. Hence, the on-time detection of errors is of great importance, especially when they are used in security-critical applications, such as military or space. In this paper, two Totally Self-Checking (TSC) designs are introduced for the two most-widely used hash functions: SHA-1 and SHA-256. To the best of authors’ knowledge, there is no previously published work presenting TSC hashing cores. The achieved fault coverage is 100% in the case of odd erroneous bits. The same coverage is achieved for even erroneous bits, if they are appropriately spread. Additionally, experimental results in terms of frequency, area, throughput, and power consumption are provided. Compared to the corresponding Duplicated with Checking (DWC) architectures, the proposed TSC-based designs are more efficient in terms of area, throughput/area, and power consumption. Specifically, the introduced TSC SHA-1 and SHA-256 cores are more efficient by 16.1% and 20.8% in terms of area and by 17.7% and 23.3% in terms of throughput/area, respectively. Also, compared to the corresponding DWC architectures, the proposed TSC-based designs are on average almost 20% more efficient in terms of power consumption. 相似文献
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Since the discovery of collision attacks against several well-known cryptographic hash functions in 2004, a rush of new cryptanalytic results cast doubt on the current hash function standards. The relatively new NIST SHA-2 standards aren't yet immediately threatened, but their long-term viability is now in question. The US National Institute of Standards and Technology (NIST) has therefore begun an international competition to select a new SHA-3 standard. This article outlines the competition, its rules, the requirements for the hash function candidates, and the process that NIST will use to select the final winning SHA-3 standard. 相似文献
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Imtiaz Ahmad Author Vitae A. Shoba Das Author Vitae 《Computers & Electrical Engineering》2005,31(6):345-360
Hash functions are common and important cryptographic primitives, which are very critical for data integrity assurance and data origin authentication security services. Field programmable gate arrays (FPGAs) being reconfigurable, flexible and physically secure are a natural choice for implementation of hash functions in a broad range of applications with different area-performance requirements. In this paper, we explore alternative architectures for the implementation of hash algorithms of the secure hash standards SHA-256 and SHA-512 on FPGAs and study their area-performance trade-offs. As several 64-bit adders are needed in SHA-512 hash value computation, new architectures proposed in this paper implement modulo-64 addition as modulo-32, modulo-16 and modulo-8 additions with a view to reduce the chip area. Hash function SHA-512 is implemented in different FPGA families of ALTERA to compare their performance metrics such as area, memory, latency, clocking frequency and throughput to guide a designer to select the most suitable FPGA for an application. In addition, a common architecture is designed for implementing SHA-256 and SHA-512 algorithms. 相似文献
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Athanasios P. Kakarountas Haralambos Michail Athanasios Milidonis Costas E. Goutis George Theodoridis 《The Journal of supercomputing》2006,37(2):179-195
Hash functions are special cryptographic algorithms, which are applied wherever message integrity and authentication are critical.
Implementations of these functions are cryptographic primitives widely used in common cryptographic schemes and security protocols
such as Internet Protocol Security (IPSec) and Virtual Private Network (VPN). In this paper, a novel FPGA implementation of
the Secure Hash Algorithm 1 (SHA-1) is proposed. The proposed architecture exploits the benefits of pipeline and re-timing
of execution through pre-computation of intermediate temporal values. Pipeline allows division of the calculation of the hash
value in four discreet stages, corresponding to the four required rounds of the algorithm. Re-timing is based on the decomposition
of the SHA-1 expression to separate information dependencies and independencies. This allows pre-computation of intermediate
temporal values in parallel to the calculation of other independent values. Exploiting the information dependencies, the fundamental
operational block of SHA-1 is modified so that maximum operation frequency is increased by 30% approximately with negligible
area penalty compared to other academic and commercial implementations. The proposed SHA-1 hash function was prototyped and
verified using a XILINX FPGA device. The implementation’s characteristics are compared to alternative implementations proposed
by the academia and the industry, which are available in the international IP market. The proposed implementation achieved
a throughput that exceeded 2,5 Gbps, which is the highest among all similar IP cores for the targeted XILINX technology. 相似文献
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The continued growth of both wired and wireless communications has triggered the revolution for the generation of new cryptographic algorithms. SHA-2 hash family is a new standard in the widely used hash functions category. An architecture and the VLSI implementation of this standard are proposed in this work. The proposed architecture supports a multi-mode operation in the sense that it performs all the three hash functions (256, 384 and 512) of the SHA-2 standard. The proposed system is compared with the implementation of each hash function in a separate FPGA device. Comparing with previous designs, the introduced system can work in higher operation frequency and needs less silicon area resources. The achieved performance in the term of throughput of the proposed system/architecture is much higher (in a range from 277 to 417%) than the other hardware implementations. The introduced architecture also performs much better than the implementations of the existing standard SHA-1, and also offers a higher security level strength. The proposed system could be used for the implementation of integrity units, and in many other sensitive cryptographic applications, such as, digital signatures, message authentication codes and random number generators. 相似文献
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Elena Andreeva Andrey Bogdanov Bart Mennink Bart Preneel Christian Rechberger 《International Journal of Information Security》2012,11(2):103-120
In 2007, the US National Institute for Standards and Technology (NIST) announced a call for the design of a new cryptographic
hash algorithm in response to vulnerabilities like differential attacks identified in existing hash functions, such as MD5
and SHA-1. NIST received many submissions, 51 of which got accepted to the first round. 14 candidates were left in the second
round, out of which five candidates have been recently chosen for the final round. An important criterion in the selection
process is the SHA-3 hash function security. We identify two important classes of security arguments for the new designs:
(1) the possible reductions of the hash function security to the security of its underlying building blocks and (2) arguments
against differential attack on building blocks. In this paper, we compare the state of the art provable security reductions
for the second round candidates and review arguments and bounds against classes of differential attacks. We discuss all the
SHA-3 candidates at a high functional level, analyze, and summarize the security reduction results and bounds against differential
attacks. Additionally, we generalize the well-known proof of collision resistance preservation, such that all SHA-3 candidates
with a suffix-free padding are covered. 相似文献