Optimized SHA-1 hash function implemented on FPGA

In order to meet the needs of higher operation speed and lower energy consumption an optimized SHA-1 algorithm is proposed.It combines two methods loop-unfolding and pre-processing.In the process intermediate variables are introduced in the iterations and pre-calculated so that the original single-threading operation can perform in a multi-threading way.This optimized algorithm exploits parallelism to shorten the critical path for hash operations.And the cycles of the original algorithm are reduced from 80 to 41 which greatly improves the operation speed.Therefore the shortened iterations of the optimized design require a smaller amount of hardware resource thus achieving a lower energy consumption. The optimized algorithm is implemented on FPGA field programmable gate array .It can achieve a throughput rate of 1.2 Gbit /s with the maximum clock frequency of 91 MHz reaching a fair balance between operation speed and throughput rate.The simulation results show that compared with other optimized SHA-1 algorithms this algorithm obtains higher operation speed and throughput rate without compromising the security of the original SHA-1 algorithm.

One-way hash function construction based on the spatiotemporal chaotic system

Based on the spatiotemporal chaotic system, a novel algorithm for constructing a one-way hash function is proposed and analysed. The message is divided into fixed length blocks. Each message block is processed by the hash compression function in parallel. The hash compression is constructed based on the spatiotemporal chaos. In each message block, the ASCII code and its position in the whole message block chain constitute the initial conditions and the key of the hash compression function. The final hash value is generated by further compressing the mixed result of all the hash compression vulues. Theoretic analyses and numerical simulations show that the proposed algorithm presents high sensitivity to the message and key, good statistical properties, and strong collision resistance.

Security analysis of a one-way hash function based on spatiotemporal chaos

The collision and statistical properties of a one-way hash function based on spatiotemporal chaos are investigated. Analysis and simulation results indicate that collisions exist in the original algorithm and, therefore, the original algorithm is insecure and vulnerable. An improved algorithm is proposed to avoid the collisions.

One-way hash function based on hyper-chaotic cellular neural network

The design of an efficient one-way hash function with good performance is a hot spot in modern cryptography researches. In this paper, a hash function construction method based on cell neural network with hyper-chaos characteristics is proposed. First, the chaos sequence is gotten by iterating cellular neural network with Runge Kutta algorithm, and then the chaos sequence is iterated with the message. The hash code is obtained through the corre- sponding transform of the latter chaos sequence. Simulation and analysis demonstrate that the new method has the merit of convenience, high sensitivity to initial values, good hash performance, especially the strong stability.

New Hash Function Based on Nonlinear Method

Hash functions are often used in the authentication of information security field. With the development of electronic commerce, the reliability of authentication is paid more and more attention to. This paper describes an N - LFSR which combined nonlinear S - box with the LF-SR, and substitutes it for CLS operator in hash function. The efficiency of new hash function is not drop and the ability of defence attack is strengthened.

Constructing a one-way hash function based on the unified chaotic system

A new one-way hash function based on the unified chaotic system is constructed. With different values of a key parameter, the unified chaotic system represents different chaotic systems, based on which the one-way hash function algorithm is constructed with three round operations and an initial vector on an input message. In each round operation, the parameters are processed by three different chaotic systems generated from the unified chaotic system. Feed-forwards are used at the end of each round operation and at the end of each element of the message processing. Meanwhile, in each round operation, parameter-exchanging operations are implemented. Then, the hash value of length 160 bits is obtained from the last six parameters. Simulation and analysis both demonstrate that the algorithm has great flexibility, satisfactory hash performance, weak collision property, and high security.

Hash function construction using weighted complex dynamical networks

A novel scheme to construct a hash function based on a weighted complex dynamical network （WCDN） generated from an original message is proposed in this paper. First, the original message is divided into blocks. Then, each block is divided into components, and the nodes and weighted edges are well defined from these components and their relations. Namely, the WCDN closely related to the original message is established. Furthermore, the node dynamics of the WCDN are chosen as a chaotic map. After chaotic iterations, quantization and exclusive-or operations, the fixed-length hash value is obtained. This scheme has the property that any tiny change in message can be diffused rapidly through the WCDN, leading to very different hash values. Analysis and simulation show that the scheme possesses good statistical properties, excellent confusion and diffusion, strong collision resistance and high efficiency.

Hash function based on the generalized Henon map

A new Hash function based on the generalized Henon map is proposed. We have obtained a binary sequence with excellent pseudo-random characteristics through improving the sequence generated by the generalized Henon map, and use it to construct Hash function. First we divide the message into groups, and then carry out the Xor operation between the ASCII value of each group and the binary sequence, the result can be used as the initial values of the next loop. Repeat the procedure until all the groups have been processed, and the final binary sequence is the Hash value. In the scheme, the initial values of the generalized Henon map are used as the secret key and the messages are mapped to Hash values with a designated length. Simulation results show that the proposed scheme has strong diffusion and confusion capability, good collision resistance, large key space, extreme sensitivity to message and secret key, and it is easy to be realized and extended.

Message Authentication with a New Quantum Hash Function

To ensure the security during the communication,we often adopt different ways to encrypt the messages to resist various attacks.However,with the computing power improving,the existing encryption and authentication schemes are being faced with big challenges.We take the message authentication as an example into a careful consideration.Then,we proposed a new message authentication scheme with the Advanced Encryption Standard as the encryption function and the new quantum Hash function as the authentication function.Firstly,the Advanced Encryption Standard algorithm is used to encrypt the result of the initial message cascading the corresponding Hash values,which ensures that the initial message can resist eavesdropping attack.Secondly,utilizing the new quantum Hash function with quantum walks can be much more secure than traditional classical Hash functions with keeping the common properties,such as one-wayness,resisting different collisions and easy implementation.Based on these two points,the message authentication scheme can be much more secure than previous ones.Finally,it is a new way to design the message authentication scheme,which provides a new thought for other researchers in the future.Our works will contribute to the study on the new encryption and authentication functions and the combination of quantum computing with traditional cryptology in the future.

Secure hash function based on chaotic tent map with changeable parameter

A new algorithm for a novel hash function, based on chaotic tent map with changeable parameter, is proposed and analyzed. The one dimensional and piecewise tent map with changeable parameters decided by the position index of blocked messages is chosen, and blocked massages translated into ASCII code values are employed as the iteration time of the chaotic tent map. The final 128-bit hash value is generated by logical XOR operation on intermediate hash values. Theoretical analysis and computer simulation indicate that the proposed algorithm can satisfy the performance requirements of hash function.

Deployment of Hash Function to Enhance Message Integrity in Wireless Body Area Network (WBAN)

Message integrity is found to prove the transfer information of patient in health care monitoring system on the human body in order to collect and communicate the human personal data. Wireless body area network (WBAN) applications are the fast growing technology trend but security and privacy are still largely ignored, since they are hard to achieve given the limited computation and energy resources available at sensor node level. In this paper, we propose simple hash based message authentication and integrity code algorithm for wireless sensor networks. We test the proposed algorithm in MATLAB on path loss model around the human body in two scenarios and compare the result before and after enhancement and show how sensors are connected with each other to prove the message integrity in monitoring health environment.

Tibetan Sorting Method Based on Hash Function

Sorting the Tibetan language quickly and accurately requires first identifying the component elements that make up Tibetan syllables and then sorting by the priority of the component.Based on the study of Tibetan text structure,grammatical rules and syllable structure,we present a structurebased Tibetan syllable recognition method that uses syllable structure instead of grammar.This method avoids complicated Tibetan grammar and recognizes the components of Tibetan syllables simply and quickly.On the basis of identifying the components of Tibetan syllables,a Tibetan syllable sorting algorithm that conforms to the language sorting rules is proposed.The core of the Tibetan syllable sorting algorithm is a hash function.Research has found that the sorting of all legal Tibetan syllables requires eight components of information.The hash function is based on this discovery and can be assigned corresponding weights according to different sorting verify the effectiveness of the Tibetan sorting algorithm,we established an experimental corpus using the Tibetan sorting standard document recognized by the majority of Tibetan users,namely the New Tibetan Orthographic Dictionary.Experiments show that this method produces results completely consistent with standard reference works,with an accuracy of 100%,and with minimal computational time.

Numeric Identifier Transmission Algorithm Using Hash Function

When developing programs or websites, it is very convenient to use relational databases, which contain powerful and convenient tools that allow to work with data very flexibly and get the necessary information in a matter of milliseconds. A relational database consists of tables and records in these tables, each table must have a primary key, in particular, it can be a number of BIGINT type, which is a unique index of a record in the table, which allows to fetch operation with maximum speed and O (1) complexity. After the operation of writing a row to the table of database, the program receives the row identifier ID in the form of a number, and in the future this ID can be used to obtain this record. In the case of a website, this could be the GET method of the http protocol with the entry ID in the request. But very often it happens that the transmission of an identifier in the clear form is not safe, both for business reasons and for security reasons of access to information. And in this case, it is necessary to create additional functionality for checking access rights and come up with a way to encode data in such a way that it would be impossible to determine the record identifier, and this, in turn, leads to the fact that the program code becomes much more complicated and also increases the amount of data, necessary to ensure the operation of the program. This article presents an algorithm that solves these problems “on the fly” without complicating the application logic and does not require resources to store additional information. Also, this algorithm is very reliable since it is based on the use of hash functions and synthesized as a result of many years of work related to writing complex systems that require an increased level of data security and program performance.

Constructing Hash Function Based on Coupled Network Generated by Logarithmic Map

In this paper,based on coupled network generated by chaotic logarithmic map,a novel algorithm for constructing hash functions is proposed,which can transform messages and can establish a mapping from the transformed messages to the coupled matrix of the network.The network model is carefully designed to ensure the network dynamics to be chaotic.Through the chaotic iterations of the network,quantization and exclusive-or (XOR) operations,the algorithm can construct hash value with arbitrary length.It is shown by simulations that the algorithm is extremely sensitive to the initial values and the coupled matrix of the network,and has excellent performance in one-way,confusion and diffusion,and collision resistance.

基于Simhash算法的题库查重系统的设计与实现

Simhash算法是一种基于局部敏感哈希(LSH)的技术,以其快速的计算速度和高度的查重准确性而知名。该算法通过将文本特征转换为二进制码,进而通过计算这些二进制码之间的汉明距离来评估文本的相似度。在文本去重和重复文档检测等多个领域,Simhash算法已经展现出了显著的效果。鉴于此,将Simhash算法应用于题库查重具有很高的可行性和实际应用价值。

基于多重熵Hash及Box-Cox蓄电池续航时长分析与仿真

现代工业生产中,蓄电池是市电停电后通信网络业务能够持续运行的重要保障,是化解网络风险发生的重要一环。针对目前通信行业蓄电池智能化管理水平不高,尤其对于蓄电池的剩余寿命及续航时长无法测算,导致通信机房停电后无法准确预估蓄电池的续航时长。针对该问题,首先设计了一种基于信息熵的多重哈希(Hash)查询方法,然后提出了一种基于对数似然函数优化方法的Box-Cox算法,实现蓄电池时序运维数据续航时长的平稳化处理。实验结果表明对于大量的通信机房运维数据,通过基于熵的多重哈希(Hash)方法进行数据查询结构设计并使用最优化参数的Box-Cox算法可以有效计算得到蓄电池的续航时长。该方法能够将蓄电池机房运维数据转化为蓄电池续航时长生产知识数据,实现通信机房蓄电池能耗的有效管理运营,实际生产实践也证明了该方法的可行性。

RFID系统的安全性和隐私保护方法

RFID(Radio Frequency IDentification)系统射频标签结构简单,且与阅读器间采用无线方式传输数据,易产生隐私泄露和受到安全攻击。针对该问题,文中提出通过双向轻权认证协议来保护RFID系统的安全性和隐私。该协议通过随机化标签的秘密信息再哈希的方法生成会话消息,标签与阅读器间采用二次相互认证,提升了协议的安全性。该协议通过哈希运算确保认证过程中会话信息的保密传输和完整性,通过对标签端每次发出会话消息的随机化确保了消息的新鲜性,系统秘密信息的更新确保协议满足前向安全性。RFID认证协议不仅能抵抗窃听、追踪、重放、去同步化等攻击,还能满足RFID系统的安全性和隐私保护需要。

Hash函数的安全性研究

Hash函数用于数据完整性和消息认证,需要满足特定的密码学需求,其中最重要的就是抗碰撞。生日攻击是通用的寻找碰撞的方法,可用于攻击任何类型的Hash函数。文章讨论了生日攻击的碰撞阈值,以及平衡度对于碰撞阈值的影响,并指出近似碰撞的碰撞阈值的度量。最后提出了在新的高安全度Hash函数的设计中应该考虑到的几个问题。

关于Hash函数MD5的解析

在王小云写的关于分析MD5算法文章的基础上,对MD5算法的破译进行进一步的解析。以MD5算法第八步为例,介绍了F函数的性质和差分路径的有效控制。从手工推算和程序实现两方面对MD5算法进行了解析和测试,对王的文章进行了部分修正,进一步说明了满足差分特征的条件和关键点。这对MD5和其他Hash函数的分析破译有着重要的作用。

基于混沌查找表的单向Hash函数构造算法

提出一种基于混沌查找表的单向Hash函数构造算法。该算法通过控制符更新的混沌查找表将明文信息映射为查找表中的数据,置换出相应的信息后按照一定的规则提取长度为128 bit的Hash值。理论分析和仿真结果证明,该算法具有较好的单向性、混乱与扩散性以及抗碰撞性,满足单向Hash函数的各项性能要求。