SM3算法界面设计及安全性分析

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。     

基于局部碰撞算法的SHA-1改进算法设计与研究

SHA-1是一种哈希函数,它被广泛使用在电子商务这样的现代安全领域,特别是应用于数据加密通信、数字签名。很多的密码协议、标准中都包括了SHA-1算法,如著名的SSL、IPsec和PKCS。本文通过深入分析SHA-1算法及碰撞算法原理,找出SHA-1算法内部碰撞的原因,对算法中逻辑函数和压缩函数进行改进设计,得到基于局部碰撞算法的SHA-1改进算法。     

FPGA上SHA-1算法的流水线结构实现

哈希算法SHA-1算法广泛地应用于电子商务、商用加密软件等信息安全领域。通过对SHA-1算法的深入分析,提出了流水线结构的硬件实现方案。通过缩短关键路径,使用片内RAM代替LE寄存器实现流水线中间变量的数据传递,有效地提高了工作频率和单位SHA-1算法的计算速度。这种硬件结构在Altera系列芯片上的实现性能是Altcra商用SHA-1算法IP核的3倍以上。     

密码杂凑函数及其安全性分析

文章提出了针对密码杂凑函数及其安全性进行研究的重要意义,列举了单向杂凑函数、MD5、SHA-1等技术原理进行了技术分析,并从攻击手段入手,分析了密码杂凑函数的安全性,提出对SHA-1与MD-5的＂破解＂应客观看待的观点。     

一种基于FPGA的可重构密码芯片的设计与实现

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。     

MD5优化算法及安全性分析

针对目前MD5基本算法加密结果容易被破解的问题,在研究分析MD5、SHA-1及其系列算法加密原理的基础上,提出一种增加消息摘要长度的优化算法,使得破解时碰撞的概率减少很多倍,增强了系统加密的安全性。安全分析结果表明,MD5优化算法在保留了原算法加密速度的前提下,具有较原算法更好的抗攻击能力     

信息摘要算法MDA-192

提出了一种新的信息摘要提取算法MDA-192。应用该算法,可将任意长度小于264bit的信息压缩为固定长度(192bit)的输出(即信息摘要或数字指纹)。该算法执行速度比安全哈希算法SHA-1快一倍。可抗击生日攻击,并且具有良好的雪崩效应。可应用于信息完整性检验,检验信息是否被非法篡改。     

一种采用多种加密算法的文件加密方法

针对传统文件加密系统中加密算法单一、加密文件格式简单、安全性相对较低等问题,结合对称密码算法中的DES、RC2、Trip leDES、AES和单向散列算法SHA-256等算法,提出了一种采用多种加密算法的文件加密方案。详细地论述了加密文件格式的设计、多种加密算法动态产生的方法、加密解密过程,以及数据完整性和安全性。通过实验论证了其实用性,同时分析了其优点与不足。     

SHA-2算法在多核密码处理器上的实现研究

为了找出一种适合多核密码处理器的SHA-2算法高速实现方式,提高SHA-2算法在多核密码处理器上的执行速度。首先研究SHA-256、SHA-512算法在密码处理器上的实现方式,并研究多核密码处理器的结构特点与数据传输方式,分析SHA-2算法在多核上的高速实现原理。然后对SHA-2算法进行任务划分,提出SHA-2在多核密码处理器上的调度与映射算法并使用软件实现调度算法。在ASIC上的仿真验证结果表明,经优化后的SHA-2算法在多核上并行执行吞吐率有了较大提升,满足性能上的需求。     

一种基于多模式加密算法的文件保护方案*

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.     

基于SHA-1的邮件去重算法

在邮件服务端和邮件客户端,重复邮件浪费了大量资源。该文提出一种基于SHA-1的邮件去重算法,将邮件按大小分开处理,根据Hash值快速去除正文相同或相似的重复邮件。实验结果表明了该算法的有效性,其运行速度比传统方法快。     

SHA-3候选算法Keccak的Matlab设计与实现

由KIST发起的新一代Hash函数标准SHA-3的全球公开征集过程目前已进入最后一轮筛选,Kcccak是进入最后一轮的J个候选者之一。介绍了Keccak算法及特点,给出了一种基于Matlab、带有图形界面GUI的Keccak程序设计与实现过程。本程序既可用于实际的Keccak Hash值运算,最重要的是为Keccak的教学与研究提供了一个方便直观的工具。     

High-Speed FPGA Implementation of Secure Hash Algorithm for IPSec and VPN Applications

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.     

The NIST Cryptographic Workshop on Hash Functions

In light of recent breakthroughs on the cryptanalysis of hash functions, the US National Institute for Standards and Technology (NIST) organized a workshop to solicit input on the current status of the Secure Hash Algorithm-1 (SHA-1) family of hash functions.     

A new efficient medical image cipher based on hybrid chaotic map and DNA code

In this paper, we propose a novel medical image encryption algorithm based on a hybrid model of deoxyribonucleic acid (DNA) masking, a Secure Hash Algorithm SHA-2 and a new hybrid chaotic map. Our study uses DNA sequences and operations and the chaotic hybrid map to strengthen the cryptosystem. The significant advantages of this approach consist in improving the information entropy which is the most important feature of randomness, resisting against various typical attacks and getting good experimental results. The theoretical analysis and experimental results show that the algorithm improves the encoding efficiency, enhances the security of the ciphertext, has a large key space and a high key sensitivity, and is able to resist against the statistical and exhaustive attacks.

     

Hash key-based image encryption using crossover operator and chaos

This paper proposes a color image encryption scheme using one-time keys based on crossover operator, chaos and the Secure Hash Algorithm(SHA-2). The (SHA-2) is employed to generate a 256-bit hash value from both the plain-image and the secret hash keys to make the key stream change in each encryption process. The SHA-2 value is employed to generate three initial values of the chaotic system. The permutation-diffusion process is based on the crossover operator and XOR operator, respectively. Experimental results and security analysis show that the scheme can achieve good encryption result through only one round encryption process, the key space is large enough to resist against common attacks,so the scheme is reliable to be applied in image encryption and secure communication.     

Hardware implementation analysis of SHA-256 and SHA-512 algorithms on FPGAs

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.     

对哈希算法SHA-1的分析和改进

研究了哈希算法的相关问题,对常用哈希算法SHA—1从安全性和运算效率方面进行了较深入分析,并由此提出了对该算法的几点改进,使改进后的算法在安全性及运算效率方面较原算法均有所提高。同时还提出了一种安全散列值的计算方法。     

基于DS2432和FPGA的IFF加密方法

本文主要论述了一种高级别的、针对FPGA的、基于IFF概念的加密方法。该方法利用SHA算法,通过配置FPGA内部的数据加密内核,进行与DS2432的指令问答完成身份验证过程。在目前的大多数数字系统中,这种方法可有效地防止软硬件的非法拷贝,具有很高的安全性。     

SHA-256输出序列的随机性研究

密码学中Hash函数能够用于数据完整性和消息认证以及数字签名,SHA-256是使用最广泛的一种Hash函数。针对SHA-256,用已有统计检测方法中的x2检验对其进行了随机性测试以及雪崩效应的测试,并对测试结果进行了分析讨论,指出了该算法中的一些不足之处,并验证了算法的有效性。