scholarly journals Performance and Statistical Analysis of Stream ciphers in GSM Communications

2020 ◽  
Vol 16 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Nagendar Yerukala ◽  
V Kamakshi Prasad ◽  
Allam Apparao
Keyword(s):  
Statistical Analysis ◽  
Stream Cipher ◽  
Statistical Tests ◽  
Stream Ciphers ◽  
Test Suite ◽  
Secret Key ◽  
Initial State ◽  
Detailed Statistical Analysis ◽  
Almost All ◽  
The Given

For a stream cipher to be secure, the keystream generated by it should be uniformly random with parameter 1/2.Statistical tests check whether the given sequence follow a certain probability distribution. In this paper, we perform a detailed statistical analysis of various stream ciphers used in GSM 2G,3G, 4G and 5G communications. The sequences output by these ciphers are checked for randomness using the statistical tests defined by the NIST Test Suite. It should also be not possible to derive any information about secret key and the initial state ofthe cipher from the keystream. Therefore, additional statisticaltests based on properties like Correlation between Keystreamand Key, and Correlation between Keystream and IV are also performed. Performance analysis of the ciphers also has been done and the results tabulated. Almost all the ciphers pass thetests in the NIST test suite with 99% confidence level. For A5/3stream cipher, the correlation between the keystream and key is high and correlation between the keystream and IV is low when compared to other ciphers in the A5 family.

scholarly journals On the Statistical Analysis of ZUC, Espresso and Grain v1

2021 ◽  
pp. 384-390
Author(s):  
Saurabh Shrivastava ◽  
K. V. Lakshmy ◽  
Chungath Srinivasan
Keyword(s):  
Statistical Analysis ◽  
Stream Cipher ◽  
Internal State ◽  
Statistical Tests ◽  
Stream Ciphers ◽  
Hamming Weight ◽  
Secret Key ◽  
State Correlation ◽  
Very High

A stream cipher generates long keystream to be XORed with plaintext to produce ciphertext. A stream cipher is said to be secure if the keystream that it produces is consistently random. One of the ways by which we can analyze stream ciphers is by testing randomness of the keystream. The statistical tests mainly try to find if any output keystream leaks any information about the secret key or the cipher’s internal state and also check the randomness of the keystream. We have applied these tests to different keystreams generated by ZUC, Espresso and Grain v1 stream ciphers to check for any weaknesses. We have also proposed four new statistical tests to analyze the internal state when the hamming weight of key and IV used is very high or low. Out of these four tests, Grain v1 fails the last test i.e. internal state correlation using high hamming weight IV.

scholarly journals Atom: A Stream Cipher with Double Key Filter

2021 ◽  
pp. 5-36
Author(s):  
Subhadeep Banik ◽  
Andrea Caforio ◽  
Takanori Isobe ◽  
Fukang Liu ◽  
Willi Meier ◽  
...  
Keyword(s):  
Stream Cipher ◽  
Internal State ◽  
Common Knowledge ◽  
Basic Structure ◽  
Stream Ciphers ◽  
Security Level ◽  
Secret Key ◽  
Internal States ◽  
The Face

It has been common knowledge that for a stream cipher to be secure against generic TMD tradeoff attacks, the size of its internal state in bits needs to be at least twice the size of the length of its secret key. In FSE 2015, Armknecht and Mikhalev however proposed the stream cipher Sprout with a Grain-like architecture, whose internal state was equal in size with its secret key and yet resistant against TMD attacks. Although Sprout had other weaknesses, it germinated a sequence of stream cipher designs like Lizard and Plantlet with short internal states. Both these designs have had cryptanalytic results reported against them. In this paper, we propose the stream cipher Atom that has an internal state of 159 bits and offers a security of 128 bits. Atom uses two key filters simultaneously to thwart certain cryptanalytic attacks that have been recently reported against keystream generators. In addition, we found that our design is one of the smallest stream ciphers that offers this security level, and we prove in this paper that Atom resists all the attacks that have been proposed against stream ciphers so far in literature. On the face of it, Atom also builds on the basic structure of the Grain family of stream ciphers. However, we try to prove that by including the additional key filter in the architecture of Atom we can make it immune to all cryptanalytic advances proposed against stream ciphers in recent cryptographic literature.

scholarly journals Security and performance analysis of SCDSP

2016 ◽  
Vol 2 (1) ◽  
Author(s):  
Fardous Mohamed Eljadi ◽  
Imad Fakhri Al-Shaikhli
Keyword(s):  
Performance Analysis ◽  
Stream Cipher ◽  
Security Analysis ◽  
Dynamic Structure ◽  
Stream Ciphers ◽  
Security Level ◽  
Dynamic Parameters ◽  
Secret Key ◽  
And Performance ◽  
A Performance

There are few approaches that attempt to add dynamicity to the structure of stream ciphers in order to improve their security level. SCDSP is a dynamic stream cipher that based on these approaches. It uses dynamic structure and parameters to increase the complexity of the cipher to improve its security level. The dynamic parameters are specified using bits from the secret key. In this paper, SCDSP is evaluated by conducting a performance and security analysis. Furthermore, a comparison between SCDSP and the seven winners of eSTREAM competition is performed. The results show that SCDSP is very promising for practical use.

scholarly journals Cryptanalysis of Plantlet

2019 ◽  
pp. 103-120
Author(s):  
Subhadeep Banik ◽  
Khashayar Barooti ◽  
Takanori Isobe
Keyword(s):  
Stream Cipher ◽  
Internal State ◽  
Polynomial Equations ◽  
Secret Key ◽  
Key Recovery ◽  
Internal States ◽  
Key Recovery Attack ◽  
System Of Polynomial Equations ◽  
The Given ◽  
Generic Time

Plantlet is a lightweight stream cipher designed by Mikhalev, Armknecht and Müller in IACR ToSC 2017. It has a Grain-like structure with two state registers of size 40 and 61 bits. In spite of this, the cipher does not seem to lose in security against generic Time-Memory-Data Tradeoff attacks due to the novelty of its design. The cipher uses a 80-bit secret key and a 90-bit IV. In this paper, we first present a key recovery attack on Plantlet that requires around 276.26 Plantlet encryptions. The attack leverages the fact that two internal states of Plantlet that differ in the 43rd LFSR location are guaranteed to produce keystream that are either equal or unequal in 45 locations with probability 1. Thus an attacker can with some probability guess that when 2 segments of keystream blocks possess the 45 bit difference just mentioned, they have been produced by two internal states that differ only in the 43rd LFSR location. Thereafter by solving a system of polynomial equations representing the keystream bits, the attacker can find the secret key if his guess was indeed correct, or reach some kind of contradiction if his guess was incorrect. In the latter event, he would repeat the procedure for other keystream blocks with the given difference. We show that the process when repeated a finite number of times, does indeed yield the value of the secret key. In the second part of the paper, we observe that the previous attack was limited to internal state differences that occurred at time instances that were congruent to 0 mod 80. We further observe that by generalizing the attack to include internal state differences that are congruent to all equivalence classed modulo 80, we lower the total number of keystream bits required to perform the attack and in the process reduce the attack complexity to 269.98 Plantlet encryptions.

scholarly journals NOCAS : A Nonlinear Cellular Automata Based Stream Cipher

2011 ◽  
Vol DMTCS Proceedings vol. AP,... (Proceedings) ◽  
Author(s):  
Sandip Karmakar ◽  
Dipanwita Roy Chowdhury
Keyword(s):  
Cellular Automata ◽  
Stream Cipher ◽  
State Of The Art ◽  
Building Blocks ◽  
The State ◽  
Stream Ciphers ◽  
Initialization Vector ◽  
International Audience ◽  
Suitable Structure ◽  
Almost All

International audience LFSR and NFSR are the basic building blocks in almost all the state of the art stream ciphers like Trivium and Grain-128. However, a number of attacks are mounted on these type of ciphers. Cellular Automata (CA) has recently been chosen as a suitable structure for crypto-primitives. In this work, a stream cipher is presented based on hybrid CA. The stream cipher takes 128 bit key and 128 bit initialization vector (IV) as input. It is designed to produce $\mathrm{2^{128}}$ random keystream bits and initialization phase is made faster 4 times than that of Grain-128. We also analyze the cryptographic strength of this cipher. Finally, the proposed cipher is shown to be resistant against known existing attacks.

Deskripsi Kesulitan Belajar Siswa Berdasarkan Karakteristik Lerner dalam Menyelesaikan Soal Geometri

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Nazom Murio ◽  
Roseli Theis
Keyword(s):  
Qualitative Research ◽  
Visual Perception ◽  
Learning Difficulties ◽  
Research Subjects ◽  
Visual Objects ◽  
Almost All ◽  
Personality Classification ◽  
The Given ◽  
Classification Test ◽  
Descriptive Qualitative

Geometri adalah bagian matematika yang sangat dekat dari siswa, karena hampir semua objek visual yang ada di sekitar siswa adalah objek geometri, tetapi tidak semua siswa menyukai pembelajaran yang menyertakan gambar, sehingga memungkinkan siswa mengalami kesulitan dalam belajar geometri. Tujuan dari penelitian ini adalah untuk menggambarkan kesulitan belajar siswa berdasarkan karakteristik Lerner dalam menyelesaikan pertanyaan geometri. Jenis penelitian ini adalah penelitian deskriptif kualitatif. Subjek penelitian adalah siswa dengan kepribadian wali yang mengalami kesulitan belajar di kelas IX A SMP N 30 Muaro Jambi. Instrumen yang digunakan dalam penelitian ini adalah penulis sendiri, lembar tes klasifikasi kepribadian, lembar tes kesulitan belajar, dan pedoman wawancara. Hasil penelitian menunjukkan siswa dengan kepribadian wali yang mengalami kesulitan belajar, 100% mengalami kelainan persepsi visual, di mana siswa mengalami kesulitan dalam menentukan seperti apa bangun datar pada masalah tersebut. 60% mengalami kesulitan mengenali dan memahami simbol, di mana siswa melihat simbol "//" sebagai simbol untuk kesesuaian. Serta 40% mengalami kesulitan dalam bahasa dan membaca, di mana siswa kesulitan dalam memahami pertanyaan yang diberikan.   Geometry is a very close mathematical part of the student, because almost all visual objects that exist around the students are objects of geometry, but not all students like learning that includes images, thus allowing students to have difficulty in learning geometry. The purpose of this research is to describe students' learning difficulties based on Lerner's characteristic in solving the geometry question. This type of research is descriptive qualitative research. Research subjects were students with guardian personality who had difficulty studying in class IX A SMP N 30 Muaro Jambi. Instruments used in this study are the authors themselves, personality classification test sheets, learning difficulties test sheets, and interview guidelines. The results showed students with guardian personality who experienced learning difficulties, 100% experienced visual perception abnormalities, where students have difficulty in determining what kind of flat wake on the matter. 60% have difficulty recognizing and understanding symbols, where students see the symbol "//" as a symbol for conformity. As well as 40% have difficulty in language and reading, where students difficulty in understanding the given question.

scholarly journals Cryptanalysis of Loiss Stream Cipher-Revisited

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Lin Ding ◽  
Chenhui Jin ◽  
Jie Guan ◽  
Qiuyan Wang
Keyword(s):  
Time Complexity ◽  
Stream Cipher ◽  
Linear Equations ◽  
Data Complexity ◽  
Secret Key ◽  
Key Recovery ◽  
Systems Of Linear Equations ◽  
Key Recovery Attack ◽  
Better Than

Loiss is a novel byte-oriented stream cipher proposed in 2011. In this paper, based on solving systems of linear equations, we propose an improved Guess and Determine attack on Loiss with a time complexity of 2231and a data complexity of 268, which reduces the time complexity of the Guess and Determine attack proposed by the designers by a factor of 216. Furthermore, a related key chosenIVattack on a scaled-down version of Loiss is presented. The attack recovers the 128-bit secret key of the scaled-down Loiss with a time complexity of 280, requiring 264chosenIVs. The related key attack is minimal in the sense that it only requires one related key. The result shows that our key recovery attack on the scaled-down Loiss is much better than an exhaustive key search in the related key setting.

Practical R for biologists: an introduction

2021 ◽  
Keyword(s):  
Statistical Tests ◽  
Statistical Modelling ◽  
Biological Data ◽  
Early Years ◽  
Main Text ◽  
Biological Data Analysis ◽  
Base Functions ◽  
Almost All ◽  
Selection Of ◽  
R Functions

Abstract R is an open-source statistical environment modelled after the previously widely used commercial programs S and S-Plus, but in addition to powerful statistical analysis tools, it also provides powerful graphics outputs. In addition to its statistical and graphical capabilities, R is a programming language suitable for medium-sized projects. This book presents a set of studies that collectively represent almost all the R operations that beginners, analysing their own data up to perhaps the early years of doing a PhD, need. Although the chapters are organized around topics such as graphing, classical statistical tests, statistical modelling, mapping and text parsing, examples have been chosen based largely on real scientific studies at the appropriate level and within each the use of more R functions is nearly always covered than are simply necessary just to get a p-value or a graph. R comes with around a thousand base functions which are automatically installed when R is downloaded. This book covers the use of those of most relevance to biological data analysis, modelling and graphics. Throughout each chapter, the functions introduced and used in that chapter are summarized in Tool Boxes. The book also shows the user how to adapt and write their own code and functions. A selection of base functions relevant to graphics that are not necessarily covered in the main text are described in Appendix 1, and additional housekeeping functions in Appendix 2.

Be Careful, if You Learn Geography for 8th Grade with „Ucha.se“

2021 ◽  
Vol 30 (1) ◽  
pp. 37-53
Author(s):  
Ivan Drenovski ◽  
Keyword(s):  
Test Items ◽  
Educational Site ◽  
8Th Grade ◽  
Basic Concepts ◽  
Almost All ◽  
The Given

The article analyses the content of the video lessons and corresponding to them test items in Geography and Economics for 8 th grade, available for a fee, on the educational site "Ucha.se". The studied curriculum is related to the introduction of basic concepts and explanations of key processes studied by geology, geophysics, astronomy, geochemistry, geomorphology, meteorology, climatology, hydrology, biology and other sciences. There are serious lapses in the scientific reliability and correctness of the given statements in almost all lessons. Examples of factual errors, incorrectly asked questions, inaccurate images and pseudo-scientific simplifications are pointed.

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