Final Hash Value Research Articles

A Simple Secure Hash Function Scheme Using Multiple Chaotic Maps

The chaotic maps posses high parameter sensitivity, random-like behavior and one-way computations, which favor the construction of cryptographic hash functions. In this paper, we propose to present a novel hash function scheme which uses multiple chaotic maps to generate efficient variable-sized hash functions. The message is divided into four parts, each part is processed by a different 1D chaotic map unit yielding intermediate hash code. The four codes are concatenated to two blocks, then each block is processed through 2D chaotic map unit separately. The final hash value is generated by combining the two partial hash codes. The simulation analyses such as distribution of hashes, statistical properties of confusion and diffusion, message and key sensitivity, collision resistance and flexibility are performed. The results reveal that the proposed anticipated hash scheme is simple, efficient and holds comparable capabilities when compared with some recent chaos-based hash algorithms.

Chaotic hash function based on the dynamic S-Box with variable parameters

We present a chaotic hash function based on the dynamic S-Box with variable parameters in this paper. More specifically, we first exploit the piecewise linear chaotic map to obtain four initial buffers and an initial hash value. Then, we divide a randomly chosen message into message blocks and assign the four buffers and current message block to a transfer function to produce variable parameters and initial values of the PWLCM and logistic map for constructing a dynamic S-Box, which is then used for updating the four buffers. After all the message blocks are processed, the final hash value is generated by cascading the buffers and then applying XOR operation with the last hash value. Finally, we conduct performance evaluation on the proposed hash algorithm in terms of sensitivity, confusion and diffusion properties, collision resistances, speed analysis, randomness tests, and comparison with other algorithms, and the results demonstrate that the proposed algorithm has good statistical properties, strong collision resistances and better performance compared with other schemes.

A fast and efficient hash function based on generalized chaotic mapping with variable parameters

We present a fast and efficient hash algorithm based on a generalized chaotic mapping with variable parameters in this paper. We first define a generalized chaotic mapping by utilizing piecewise linear chaotic map and trigonometric functions. Then, we convert the arbitrary length of message into the corresponding ASCII values and perform 6-unit iterations with variable parameters and message values based on the generalized chaotic mapping. The final hash value is obtained by cascading extracted bits from iteration state values. We excessively evaluate the proposed algorithm in terms of distribution of hash value, sensitivity of hash value to the message and secret keys, statistical analysis of diffusion and confusion, analysis of birthday attacks and collision resistance, analysis of secret keys, analysis of speed, and comparison with other algorithms, and the results illustrate that the suggested algorithm is fast, efficient, and enough simple and has good confusion and diffusion capabilities, strong collision resistance, and a high level of security.

Security Analysis of MD5 Algorithm in Password Storage

Hashing algorithms are commonly used to convert passwords into hashes which theoretically cannot be deciphered. This paper analyses the security risks of the hashing algorithm MD5 in password storage and discusses different solutions, such as salts and iterative hashing. We propose a new approach to using MD5 in password storage by using external information, a calculated salt and a random key to encrypt the password before the MD5 calculation. We suggest using key stretching to make the hash calculation slower and using XOR cipher to make the final hash value impossible to find in any standard rainbow table.

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 values. 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.

A Fault Detection Scheme for the FPGA Implementation of SHA-1 and SHA-512 Round Computations

The Secure Hash Algorithm is the most popular hash function currently used in many security protocols such as SSL and IPSec. Like other cryptographic algorithms, the hardware implementation of hash functions is of great importance for high speed applications. Because of the iterative structure of hash functions, a single error in their hardware implementation could result in a large number of errors in the final hash value. In this paper, we propose a novel time-redundancy-based fault diagnostic scheme for the implementation of SHA-1 and SHA-512 round computations. This scheme can detect permanent as well as transient faults as opposed to the traditional time redundancy technique which is only capable of detecting transient errors. The proposed design does not impose significant timing overhead to the original implementation of SHA-1 and SHA-512 round computation. We have implemented the proposed design for SHA-1 and SHA-512 on Xilinx xc2p7 FPGA. It is shown that for the proposed fault detection SHA-1 and SHA-512 round computations, there are, respectively, 3% and 10% reduction in the throughput with 58% and 30% area overhead as compared to the original schemes. The fault simulation of the implementation shows that almost 100% fault coverage can be achieved using the proposed scheme for transient and permanent faults.

Parallel Hash function construction based on chaotic maps with changeable parameters

A parallel Hash algorithm construction based on chaotic maps with changeable parameters is proposed and analyzed in this paper. The two main characteristics of the proposed algorithm are parallel processing mode and message expansion. The algorithm translates the expanded message blocks into the corresponding ASCII code values as the iteration times, iterates the chaotic asymmetric tent map and then the chaotic piecewise linear map, continuously, with changeable parameters dynamically obtained from the position index of the corresponding message blocks, to generate decimal fractions, then rounds the decimal fractions to integers, and finally cascades these integers to construct intermediate Hash value. Final Hash value with the length of 128-bit is generated by logical XOR operation of intermediate Hash values. Theoretical analysis and computer simulation indicate that the proposed algorithm satisfies the performance requirements of a secure Hash function.

Parallel hash function construction based on coupled map lattices

In this paper, the parallel structure of hash function is analyzed. Then, a parallel hash function based on coupled map lattices is proposed. The message is partitioned into blocks with fixed length. The message block is firstly processed by the hash round function. The final hash value is the mixed result of all the outputs of the hash round functions. The hash round functions are mainly implemented by the coupled map lattices and can work in a parallel mode, which guarantees good security and high efficiency. Theoretic analyses and numerical simulations both show that the proposed hash algorithm possesses good statistical properties, strong collision resistance and high efficiency. These properties make it a good candidate for hash on parallel computing platform.

Construction of optical Hash function based on nonlinear cascaded Fourier transform

A method of constructing optical Hash function based on nonlinear cascaded Fourier transform is proposed. The proposed method consists of two single one-way encryption processes. In the first process, the digital information is divided to several data blocks with 512-bit each. The data blocks are encoded to 8 by 8 sub-images with 256 gray scales, creating information planes. Then take a nonlinear cascaded Fourier transform of sub-image to generate a data matrix through an optical/digital hybrid system. By extending the data matrix we get four information planes. Again, taking nonlinear cascaded Fourier transform to built information planes, we get a Hash value 64-bit long （hash1）. In the second process, we shift cydically every numerical value of the original information planes by 4-bit, constructing auxiliary information planes. Thereafter we take the same operations as we have done in the first process to the Hash value （hash2）. Once hash1 and hash2 obtained, they are combined to form a final Hash value 128-bit long （hash）. Furthermore, the avalanche effect coefficient （AEC） was also proposed to evaluate the performance of the optical Hash function. Theoretical analysis and simulation results are presented to show the effectiveness of optical Hash function constructed by our approach and the constructed optical Hash function has good performance of avalanche effect and collision resistance.

Analysis and improvement of a chaos-based Hash function construction

The construction of a new Hash function attracts much attention recently. In Kwok and Tang (2005) [Kwok HS, Tang WKS. A chaos-based cryptographic Hash function for message authentication. Int J Bifurcat Chaos 2005;15:4043–50], a chaos-based Hash function has been proposed. In this paper, the potential flaws in the original algorithm are analyzed in detail, and then the corresponding improving measures are proposed. We enhance the influence that each bit of the final Hash value is closely related to all the bits of the message or key and a single bit change in message or key results in great changes in the final Hash value. Simulation results show that the proposed improving algorithm has strong diffusion and confusion capability, good collision resistance, extreme sensitivity to message and secret key.

Analysis and Detection Of Errors In Implementation Of SHA-512 Algorithms On FPGAs

The Secure Hash Algorithm SHA-512 is a dedicated cryptographic hash function widely considered for use in data integrity assurance and data origin authentication security services. Reconfigurable hardware devices such as Field Programmable Gate Arrays (FPGAs) offer a flexible and easily upgradeable platform for implementation of cryptographic hash functions. Owing to the iterative structure of SHA-512, even a single transient error at any stage of the hash value computation will result in large number of errors in the final hash value. Hence, detection of errors becomes a key design issue. In this paper, we present a detailed analysis of the propagation of errors to the output in the hardware implementation of SHA-512. Included in this analysis are single, transient as well as permanent faults that may appear at any stage of the hash value computation. We then propose an error detection scheme based on parity codes and hardware redundancy. We report the performance metrics such as area, memory, and throughput for the implementation of SHA-512 with error detection capability on an FPGA of ALTERA. We achieved 100% fault coverage in the case of single faults with an area overhead of 21% and with a reduced throughput of 11.6% with the error detection circuit.

Chaotic keyed hash function based on feedforward–feedback nonlinear digital filter

Abstract In this Letter, we firstly construct an n-dimensional chaotic dynamic system named feedforward–feedback nonlinear filter (FFNF), and then propose a novel chaotic keyed hash algorithm using FFNF. In hashing process, the original message is modulated into FFNF's chaotic trajectory by chaotic shift keying (CSK) mode, and the final hash value is obtained by the coarse-graining quantization of chaotic trajectory. To expedite the avalanche effect of hash algorithm, a cipher block chaining (CBC) mode is introduced. Theoretic analysis and numerical simulations show that the proposed hash algorithm satisfies the requirement of keyed hash function, and it is easy to implement by the filter structure.

One-way Hash function construction based on tangent-delay ellipse reflecting cavity-map system

An algorithm for one-way Hash function construction based on tangent-delay ellipse reflecting cavity-map system (TD-ERCS) is proposed in this paper. In the algorithm, the plaintext dealt with is first transformed into a systemic parameter sequence linearly, and then TD-ERCS is iterated in order of the parameter sequence directly, the final Hash value of 160 bits is obtained by means of the nonlinear transform on the iteration sequence, and no padding of calculation is added. Users’ keys of the algorithm can be chosen in the region［264, 2160］ arbitrarily. Theoretical analysis and basic security tests indicate that our Hash function has good one-way, weak collision property, better security than other chaotic Hash functions, and it can be realized easily with great rapidity. Our algorithm of Hash function is an ideal substitution for conventional Hash function. And also, a natural criterion (theoretical value of 85.33) to evaluate collision property of Hash function is educed in this paper.

One-way Hash function construction based on the chaotic map with changeable-parameter

An algorithm for one-way Hash function construction based on the chaotic map with changeable-parameter is proposed in this paper. A piecewise linear chaotic map with changeable-parameter P is chosen, and cipher block chaining mode (CBC) is introduced to ensure that the parameter P in each iteration is dynamically decided by the last-time iteration value and the corresponding message bit in different positions. The final Hash value is obtained by means of the linear transform on the iteration sequence. Theoretical analysis and computer simulation indicate that our algorithm can satisfy all the performance requirements of Hash function in an efficient and flexible manner. It is practicable and reliable, with high potential to be adopted for E-commerce.

One-way Hash function construction based on the chaotic map with changeable-parameter

Abstract An algorithm for one-way Hash function construction based on the chaotic map with changeable-parameter is proposed in this paper. A piecewise linear chaotic map with changeable-parameter P is chosen, and cipher block chaining mode (CBC) is introduced to ensure that the parameter P in each iteration is dynamically decided by the last-time iteration value and the corresponding message bit in different positions. The final Hash value is obtained by means of the linear transform on the iteration sequence. Theoretical analysis and computer simulation indicate that our algorithm can satisfy all the performance requirements of Hash function in an efficient and flexible manner. It is practicable and reliable, with high potential to be adopted for E-commerce.