Pseudo-random Generation Algorithm Research Articles

Discovering Unknown Non-Consecutive Double Byte Biases in RC4 Stream Cipher Algorithm

RC4 is one of the most widely used stream cipher algorithms. It is fast, easy and suitable for hardware and software. It is used in various applications, but it has a weakness in the distribution of generated key bytes. The first few bytes of Pseudo-Random Generation Algorithm (PRGA) key stream are biased or attached to some private key bytes and thus the analysis of key stream bytes makes it potential to attack RC4, and there is connection between the key stream bytes that make it weak and breakable by single- and double-byte biases attack. This work shows the analysis of RC4 key stream based on its non-consecutive double byte biases by using newly designed algorithm that calculates the bias in a standard time (seconds). The results are shown that the bias of RC4 keystream is proved and got the same results that were shown in the literature with less time and discover a set of new non-consecutive double byte biases in the positions (i) and (i+n). The analysis of 256 positions is required additional requirements such as supercomputer and the message passing interface environment that are not available in Iraq, therefore; the analysis is done for 32 positions.

Implementasi Algoritma RC4A Dalam Pengamanan Citra Digital

Digital images that are private and confidential are very vulnerable to wiretapping by irresponsible parties, especially if the images are distributed via the internet. The act of theft and abuse of secret images of course can harm the image owner. One of the techniques to reduce the above problems is by using cryptographic techniques. Cryptographic techniques can secure images by means of digital image encryption by implementing the RC4A algorithm then using the initial keyword as input in the process carried out to generate new, more random keywords, based on the Key Schedule Algorithm. (KSA) and pseudo random generation algorithm (PRGA). To determine the comparison between the original image (PlainImage) and the original image (CipherImage), processing was carried out with MeanSquareError (MSE) and PeakSiqnalToNoiseRation (PSNR). The results of this study were digital images encrypted with the RC4A algorithm in terms of time differences and image results after encryption where the time used to encrypt is shorter than the description and the image results before encryption are not the same after encryption.

The security of RC4 algorithm using keys generation depending on user's retina

Digital technologies grow more rapidly; information security threats are becoming increasingly dangerous. Advanced and various cyber-attacks and security threats, like targeted emails, and information exploitation, pose a critical threat that basically undermines our trust in the digital society. Rivest cipher 4 (RC4) algorithm is a significant cipher of a stream that could be utilized with protocols of the internet, the advantage of the RC4 algorithm is that it is simple and effective. There are several weak, especially after the pseudo-random generation algorithm (PRGA), PRGA's initially 256 rounds (the amount of the RC4 permutation). Several modified RC4 studies have been published thus far, however, they all face either standard privacy or achievement evaluation issues. This paper proposes a new RC4 algorithm that is based on the user's retina (RC4-Retina), which has solved both of these weak points it was indicated in the standard RC4 algorithm. The novelty of retina key scheduling algorithm (RKSA), which is generated by relying on the user's retina of the algorithm will modify the matrix of permutation used to configure the keys. The efficiency of the improved algorithm was measured by depending on the average security of ciphertext of different keys and different messages, results were good compared to the standard algorithm.

Settling the mystery of Zr = r in RC4

In this paper, using a matrix, at first we revisit the work of Mantin on finding the probability distribution of the RC4 permutation after the completion of the KSA. After that, we extend the same idea to analyse the probabilities during any iteration of the Pseudo Random Generation Algorithm. Next, we study the bias of Zr = r (where Zr is the r-th output keystream byte), which is one of the significant biases observed in the RC4 output keystream. This bias has played an important role in the plaintext recovery attack proposed by Isobe et al. in FSE 2013. However, the accurate theoretical explanation of the bias of Zr = r is still a mystery. Though several attempts have been made to prove this bias, none of those provides an accurate justification. Here, using the results found with the help of the probability transition matrix we justify this bias of Zr = r accurately and settle this issue. The bias obtained from our proof matches the experimental observations perfectly.

Cryptography using Random Rc4 Stream Cipher on SMS for Android-Based Smartphones

Messages sent using the default Short Message Service (SMS) application have to pass the SMS Center (SMSC) to record the communication between the sender and recipient. Therefore, the message security is not guaranteed because it may read by irresponsible people. This research proposes the RC4 stream cipher method for security in sending SMS. However, RC4 has any limitation in the Key Scheduling Algorithm (KSA) and Pseudo Random Generation Algorithm (PRGA) phases. Therefore, this research developed RC4 with a random initial state to increase the randomness level of the keystream. This SMS cryptography method applied the processes of encryption against the sent SMS followed by decryption against the received SMS. The performance of the proposed method is evaluated based on the time of encryption and decryption as well as the average correlation value. Based on the time, it shows that the length of the SMS characters sent affects the time of encryption and decryption. Meanwhile, the best correlation value achieved 0.00482.

IMPROVE THE PERFORMANCE OF MPEG VIDEO ENCRYPTION ALGORITHM USING MODIFIED RC4 ALGORITHM BASEDON CHAOTIC MAP

With rapid growth in communication techniques and multimedia application, security is becoming more important for multimedia data storage or transmission. Traditional encryption algorithm such as Advance Encryption Standard (AES) and Data Encryption Standard (DES) are not suitable for video data because it caused large computational overhead and reduce the MPEG compression efficiency. The encryption algorithm that has less computation overhead is needed. The proposed algorithm combines encryption process with MPEG video compression. Some modifications of the RC4 algorithm were proposed in this paper to enhance the performance of video encryption algorithm in terms of encryption time, compression ratio and to provide accepted level of the security. The modification of the RC4 algorithm depends on the maximum value of the plain text, chaotic map and circular shift operation. This modification will reduce the number of iteration in the Key scheduling Algorithm (KSA) and make the Pseudo Random Generator Algorithm (PRGA) depend on initial condition of chaotic maps to provide the strong shuffling inside the PRGA. The random rotation technique based on chaotic map is proposed to increase security of MPEG video. This technique depends on the value generated from chaotic map to rotate the Y blocks in I frame. The experimental results indicate that the proposed method provided better encryption times and provides sufficient level of the security. Thus the proposed method is suitable to protect the MPEG video with minimizing the overhead.

Signature attractor based pseudorandom generation algorithm

We study a chaotic attractor based pseudorandom generation algorithm. The novel scheme use a signature attractor and the logical XOR function. The output binary digits are analysed by NIST, ENT and DIEHARD statistical applications.

Random number generation system improving simulations of stochastic models of neural cells

The purpose of this work is to speed up simulations of neural tissues based on the stochastic version of the Hodgkin–Huxley model. Authors achieve that by introducing the system providing random values with desired distribution in simulation process. System consists of two parts. The first one is a high entropy fast parallel random number generator consisting of a hardware true random number generator and graphics processing unit implementation of pseudorandom generation algorithm. The second part of the system is Gaussian distribution approximation algorithm based on a set of generators of uniform distribution. Authors present hardware implementation details of the system, test results of the mentioned parts separately and of the whole system in neural cell simulation task.

Novel Hardware Implementation of Modified RC4 Stream Cipher for Wireless Network Security

This paper presents novel hardware implementation of modified RC4 stream cipher for wireless network security. The Modified RC4 algorithm proposes two changes in conventional RC4 stream cipher algorithm, one in Key Scheduling Algorithm (KSA) stage and other in Pseudorandom Generation Algorithm (PRGA) stage. This modification in KSA removed many weakness and produces random states, so that it will hard to identify any nonuniformity in the permutation after KSA. The other modification in PRGA has destroyed relation between internal states of S-boxes, which is base of many attacks on RC4. The proposed architecture uses variable key length from 1 byte to (256+256+8) 520 bytes but previous designs support maximum key length of 256 bytes. This architecture achieved throughput of 63.449 Mbps at a clock frequency of 190.349 MHz independent of key length. The system was implemented in hardware by using VHDL language and Xilinx FPGA device. General Terms Stream ciphers for wireless network security.

A fast pseudorandom number generator with BLAKE hash function

This paper presents a fast pseudorandom generation algorithm, which is based on the BLAKE hash function and can pass the random test of the NIST (National Institute of Standards and Technology) Statistical Test Suite. Through theoretical analysis and experimental imitation, our new algorithm is proven to be more secure and efficient than G-SHA1. Simultaneously, we introduce and discuss the BLAKE in detail. Its security shows that can be utilized to generate pseudorandom bit sequences, which the experimental results show the BLAKE hash function has excellent pseudorandomness. Therefore, we believe the BLAKE is one of the most potential candidate algorithms of SHA-3 program.

A complete characterization of the evolution of RC4 pseudo random generation algorithm

In this paper, we provide a complete characterization of the RC4 Pseudo Random Generation Algorithm (PRGA) for one step: i = i + 1; j = j + S [ i ]; swap( S [ i ], S [ j ]); z = S [ S [ i ] + S [ j ]]. This is the first time such an involved description is presented to get a concise view of how RC4 PRGA evolves. Considering all the permutations (we also keep in mind the Finney states), we find that the distribution of z is not uniform given i, j . A corollary of this result shows that information about j is always leaked from z . Next, studying two consecutive steps of RC4 PRGA, we prove that the index j is not produced uniformly at random given the value of j two steps ago. We also provide additional evidence of z leaking information on j . Further, we present a novel distinguisher for RC4 which shows that under certain conditions the equality of two consecutive bytes is more probable than by random association. Our analysis holds regardless of the amount of initial keystream bytes thrown away during the RC4 PRGA.

Generating Nearly Sorted Sequences – The use of measures of disorder

There have been several formal proposals for a function that evaluates disorder in a sequence. We show here that definitions that allow equivalence to an operational formulation allow for the construction of an algorithm for pseudo-random generation of nearly sorted sequences. As there is interest in comparing performance of algorithms on nearly sorted sequences during experimental evaluations of their implementation, our methods here provide the pathway for establishing the benchmarks datasets to compare such algorithms.

A universal predictor based on pattern matching

We consider a universal predictor based on pattern matching. Given a sequence X/sub 1/, ..., X/sub n/ drawn from a stationary mixing source, it predicts the next symbol X/sub n+1/ based on selecting a context of X/sub n+1/. The predictor, called the sampled pattern matching (SPM), is a modification of the Ehrenfeucht-Mycielski (1992) pseudorandom generator algorithm. It predicts the value of the most frequent symbol appearing at the so-called sampled positions. These positions follow the occurrences of a fraction of the longest suffix of the original sequence that has another copy inside X/sub 1/X/sub 2//spl middot//spl middot//spl middot/X/sub n/; that is, in SPM, the context selection consists of taking certain fraction of the longest match. The study of the longest match for lossless data compression was initiated by Wyner and Ziv in their 1989 seminal paper. Here, we estimate the redundancy of the SPM universal predictor, that is, we prove that the probability the SPM predictor makes worse decisions than the optimal predictor is O(n/sup -/spl nu//) for some 0</spl nu/< 1/2 as n/spl rarr//spl infin/. As a matter of fact, we show that we can predict K=O(1) symbols with the same probability of error.