scholarly journals Development of a Pseudo-Random Sequence Generation Function Based on the “Kuznechik” Cryptographic Algorithm

2021 ◽  
pp. 25-34
Author(s):  
Sergey Belyaev ◽  
◽  
Marina Budko ◽  
Mikhail Budko ◽  
Alexei Guirik ◽  
...  
Keyword(s):  
Random Sequence ◽  
Encryption Algorithm ◽  
Statistical Hypothesis ◽  
Statistical Hypothesis Testing ◽  
Original Algorithm ◽  
Sequence Generation ◽  
Generation Function ◽  
Cryptographic Algorithm ◽  
Random Sequence Generation ◽  
Main Component

Purpose: increasing the cryptographic strength level of the pseudo-random sequence generation function based on the «Kuznechik» encryption algorithm. Research methods: methods for constructing pseudo-random sequence generators using a strong cryptographic algorithm as a generation function in accordance with the recommendations of NIST SP 800-90. Methods of probability theory and mathematical statistics (statistical hypothesis testing, Pearson’s criterion), methods for estimating the entropy of a random process. Results: а method for development of the main component of the deterministic generator – the function for generating pseudo-random sequences based on the «Kuznechik» encryption algorithm (Russian encryption standard GOST R 34.12-2015) due to a number of the original algorithm modifications is proposed. Features of the algorithm allow to use it in a mode that combines the advantages of the well-known encryption modes of block ciphers (OFB and CTR encryption modes). A procedure for generating round keys and other modifications of the algorithm that increase its security while maintaining its performance have been developed and implemented. The generator operation was evaluated on the basis of the statistical properties of the output sequences (NIST SP 800-22 tests), Pearson’s χ2 criterion, and min-entropy (NIST 800-90B tests). According to the characteristics mentioned above, the proposed generation function is comparable with the reference version based on GOST 34.12-2015 «Kuznechik», but exceeds it in terms of security.

scholarly journals Security Analysis and Improvement of an Image Encryption Cryptosystem Based on Bit Plane Extraction and Multi Chaos

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 505
Author(s):  
Shuqin Zhu ◽  
Congxu Zhu
Keyword(s):  
Image Encryption ◽  
Random Sequence ◽  
Security Analysis ◽  
Encryption Algorithm ◽  
Original Algorithm ◽  
Plane Extraction ◽  
Bit Plane ◽  
Bit Planes ◽  
And Diffusion ◽  
Improved Algorithm

This paper analyzes the security of image encryption systems based on bit plane extraction and multi chaos. It includes a bit-level permutation for high, 4-bit planes and bit-wise XOR diffusion, and finds that the key streams in the permutation and diffusion phases are independent of the plaintext image. Therefore, the equivalent diffusion key and the equivalent permutation key can be recovered by the chosen-plaintext attack method, in which only two special plaintext images and their corresponding cipher images are used. The effectiveness and feasibility of the proposed attack algorithm is verified by a MATLAB 2015b simulation. In the experiment, all the key streams in the original algorithm are cracked through two special plaintext images and their corresponding ciphertext images. In addition, an improved algorithm is proposed. In the improved algorithm, the generation of a random sequence is related to ciphertext, which makes the encryption algorithm have the encryption effect of a “one time pad”. The encryption effect of the improved algorithm is better than that of the original encryption algorithm in the aspects of information entropy, ciphertext correlation analysis and ciphertext sensitivity analysis.

scholarly journals Risk of bias judgments for random sequence generation in Cochrane systematic reviews were frequently not in line with Cochrane Handbook

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Ognjen Barcot ◽  
Matija Boric ◽  
Tina Poklepovic Pericic ◽  
Marija Cavar ◽  
Svjetlana Dosenovic ◽  
...  
Keyword(s):  
Systematic Reviews ◽  
Random Sequence ◽  
Risk Of Bias ◽  
Sequence Generation ◽  
Random Sequence Generation

HEVC Video Encryption Algorithm Based on Integer Dynamic Coupling Tent Mapping

2020 ◽  
Vol 24 (3) ◽  
pp. 335-345 ◽  
Author(s):  
Bo Liu ◽  
Jiandong Liu ◽  
Shuhong Wang ◽  
Ming Zhong ◽  
Bo Li ◽  
...  
Keyword(s):  
High Efficiency ◽  
Random Sequence ◽  
Encryption Algorithm ◽  
Video Encryption ◽  
Dynamic Coupling ◽  
High Efficiency Video Coding ◽  
Sequence Generation ◽  
Binary Arithmetic ◽  
Key Space ◽  
Sequence Generator

A selective encryption algorithm is proposed to improve the efficiency of high efficiency video coding (HEVC) video encryption and ensure the security of HEVC videos. The algorithm adopts the integer dynamic coupling tent mapping optimization model as the pseudo-random sequence generator, and multi-core parallelization is used as the sequence generation mechanism. The binstrings during the process of context adaptive binary arithmetic coding are selected for encryption, which conforms to the features of invariable binstream and compatible format in terms of video encryption. Performance tests for six types of standard videos with different resolutions were performed. The results indicated that the encryption algorithm has a large key space and benefits from a high encryption effect.

scholarly journals Judgments of risk of bias associated with random sequence generation in trials included in Cochrane systematic reviews are frequently erroneous

2018 ◽  
Author(s):  
Ognjen Barcot ◽  
Matija Boric ◽  
Tina Poklepovic Pericic ◽  
Marija Cavar ◽  
Svjetlana Dosenovic ◽  
...  
Keyword(s):  
Systematic Reviews ◽  
Random Number ◽  
Random Sequence ◽  
Computer Software ◽  
Risk Of Bias ◽  
Controlled Trials ◽  
Sequence Generation ◽  
Randomized Controlled ◽  
Random Sequence Generation ◽  
Random Number Table

AbstractBackgroundPurpose of this study was to analyze adequacy of judgments about risk of bias (RoB) for random sequence generation in Cochrane systematic reviews (CSRs) of randomized controlled trials (RCTs).MethodsInformation was extracted from RoB tables of CSRs using automated data scraping. We categorized all comments provided as supports for judgments for RoB related to randomization. We analyzed number and type of various supporting comments and assessed adequacy of RoB judgment for randomization in line with recommendations from the Cochrane Handbook.ResultsWe analyzed 10527 RCTs that were included in 729 CSRs. For 5682 RCTs randomization was not described; for the others it was indicated randomization was done using computer/software/internet (N=2886), random number table (N=888), mechanic method (N=366), or it was incomplete/inappropriate (N=303).Overall, 1194/10125 trials (12%) had erroneous RoB judgment about randomization. The highest proportion of errors was found for trials with high RoB (28%), followed by those with low (19%), or unclear (3%). Therefore, one in eight judgments for the analyzed domain in CSRs was erroneous, and one in three if the judgment was “high risk”.ConclusionCochrane systematic reviews cannot be necessarily trusted when it comes to judgments for risk of bias related to randomized sequence generation.

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