DOCSLIB.ORG

Mathematical Monographs

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Mathematical Monographs Translations of MATHEMATICAL ONOGRAPHS M Volume 241 Boolean Functions in Coding Theory and Cryptography O. A. Logachev A. A. Salnikov V. V. Yashchenko American Mathematical Society Boolean Functions in Coding Theory and Cryptography 10.1090/mmono/241 Translations of MATHEMATICAL ONOGRAPHS M Volume 241 Boolean Functions in Coding Theory and Cryptography O. A. Logachev A. A. Salnikov V. V. Yashchenko M THE ATI A CA M L ΤΡΗΤΟΣ ΜΗ N ΕΙΣΙΤΩ S A O C C I I American Mathematical Society R E E T ΑΓΕΩΜΕ Y M A Providence, Rhode Island F O 8 U 88 NDED 1 EDITORIAL COMMITTEE AMS Subcommittee Robert D. MacPherson Grigorii A. Margulis James D. Stasheff (Chair) ASL Subcommittee Steffen Lempp (Chair) IMS Subcommittee Mark I. Freidlin (Chair) O. A. Logaqev, A. A. Salnikov, V. V. wenko BULEVY FUNKCII V TEORII KODIROVANI I KRIPTOGRAFII M.: MCNMO, 2004 This work was originally published in Russian by Izdatelstvo MCNMO under the title “Bulevy funkcii v teorii kodirovani i kriptografii” c 2004. The present translation was created under license for the American Mathematical Society and is pub- lished by permission. Translated by Svetla Nikova 2000 Mathematics Subject Classification. Primary 94–02; Secondary 94A60, 94C10. For additional information and updates on this book, visit www.ams.org/bookpages/mmono-241 Library of Congress Cataloging-in-Publication Data Logachev, Oleg A. [Bulevy funktsii v teori kodirovaniia i kriptologii. English] Boolean functions in coding theory and cryptography / O.A. Logachev, A.A. Salnikov, V.V. Yashchenko ; translated by Svetla Nikova. p. cm. — (Translations of mathematical monographs ; v. 241) Includes bibliographical references and index. ISBN 978-0-8218-4680-3 (alk. paper) 1. Coding theory. 2. Cryptography. 3. Algebra, Boolean. I. Salnikov, A. A. (Aleksei Alek- sandrovich) II. IAshchenko, V. V. III. Title. QA268.L6413 2011 003.54—dc23 2011035308 Copying and reprinting. Individual readers of this publication, and nonprofit libraries acting for them, are permitted to make fair use of the material, such as to copy a chapter for use in teaching or research. Permission is granted to quote brief passages from this publication in reviews, provided the customary acknowledgment of the source is given. Republication, systematic copying, or multiple reproduction of any material in this publication is permitted only under license from the American Mathematical Society. Requests for such permission should be addressed to the Acquisitions Department, American Mathematical Society, 201 Charles Street, Providence, Rhode Island 02904-2294 USA. Requests can also be made by e-mail to [email protected]. c 2012 by the American Mathematical Society. All rights reserved. The American Mathematical Society retains all rights except those granted to the United States Government. Printed in the United States of America. ∞ The paper used in this book is acid-free and falls within the guidelines established to ensure permanence and durability. Visit the AMS home page at http://www.ams.org/ 10987654321 171615141312 Contents Foreword vii Preface ix Notation xi Chapter 1. Arithmetics of Finite Fields and Polynomials 1 1.1. Basic Algebra 1 1.2. Construction of finite fields 19 1.3. Polynomials over finite fields 28 Comments to Chapter 1 35 Chapter 2. Boolean Functions 37 2.1. Basic concepts and definitions 37 2.2. Numerical and metric characteristics 44 2.3. Autocorrelation and crosscorrelation 56 2.4. Group algebra of Boolean functions 61 2.5. Cryptographic properties of Boolean functions and mappings 65 2.6. Covering sequences of Boolean functions 74 Comments to Chapter 2 76 Chapter 3. Classifications of Boolean Functions 77 3.1. Group equivalence of mappings. Polya’s theorem 77 3.2. Classification of Boolean functions of five variables 83 3.3. Classification of quadratic Boolean functions 91 3.4. Classification of homogeneous cubic forms of 8 variables 99 3.5. RM-equivalence of Boolean functions 101 Comments to Chapter 3 104 Chapter 4. Linear Codes over the Field F2 107 4.1. Basic properties of linear block codes 107 4.2. The decoding problem 116 4.3. Cyclic codes 120 4.4. Some classes of primitive cyclic codes 131 Comments to Chapter 4 136 Chapter 5. Reed–Muller Codes 139 5.1. General properties of the Reed–Muller codes 139 5.2. Reed’s decoding algorithm 146 5.3. First order Reed–Muller codes and connections with other codes 150 5.4. Reed–Muller codes of second order and related codes 157 v vi CONTENTS 5.5. Classification of Boolean functions and Reed–Muller codes of the 3rd order 160 Comments to Chapter 5 163 Chapter 6. Nonlinearity 165 6.1. Nonlinearity as a measure of cryptographic quality 165 6.2. Maximum-nonlinear bent functions and their properties 166 6.3. Some classes of maximum-nonlinear bent functions 172 6.4. Partially maximum-nonlinear (partially bent) functions and their properties 177 6.5. Plateaued functions and partially defined mn-bent functions 179 6.6. Hyperbent functions 188 6.7. Biorthogonal bases 189 Comments to Chapter 6 192 Chapter 7. Correlation Immunity and Resiliency 195 7.1. Main definitions and properties 195 7.2. The inheritance of properties under restrictions of Boolean functions 208 7.3. General methods for constructing correlation-immune functions and resilient mappings 214 7.4. Nonlinearity of correlation-immune and resilient functions 218 7.5. Construction of resilient Boolean functions with good cryptographic properties 222 7.6. Covering sequences of correlation-immune and resilient functions 226 7.7. Quadratic resilient Boolean functions of maximum order 235 Comments to Chapter 7 237 Chapter 8. Codes, Boolean Mappings, and Their Cryptographic Properties 239 8.1. Almost perfect nonlinear and almost bent mappings 239 8.2. Coding-theoretic approach to the study of APN and AB mappings 249 8.3. Cyclic codes and Boolean mappings 255 8.4. Avalanche criteria and propagation criteria 261 8.5. Construction of Boolean functions satisfying the propagation criterion of degree k and order t 265 8.6. Global avalanche characteristics of Boolean functions 266 Comments to Chapter 8 269 Chapter 9. Basics of Cryptanalysis 271 9.1. The Berlekamp–Massey algorithm. Linear complexity 271 9.2. Principles of the statistical method for cryptanalysis of block ciphers 281 9.3. Principles of the correlation cryptanalysis method 287 9.4. Principles of the linear cryptanalysis method 295 9.5. Principles of the difference (differential) cryptanalysis method 300 Comments to Chapter 9 301 Bibliography 305 Index 329 Foreword For the last 10 years there have been practically no books in Russian which have the word “cryptography” in the title. Nowadays many people already know that cryptography is the science which studies ciphers, and that only cryptography gives the most reliable tools for ensuring the security of information technology. However, there are not many specialists in this area, because in order to fully understand cryptography it is necessary to have knowledge in many scientific branches such as mathematics, physics, communication theory, and cybernetics. Thus, at present, cryptography (the theoretical branch of cryptology) becomes a university science. A detailed discussion of this issue has been held during the two conferences at Moscow State University (MGU): “Moscow University and development of cryptography in Russia” (October 17–18, 2002) and “Mathematics and information technology security” (October 23–24, 3003). Institute for Problems of Information Security, a new division of MGU, pub- lishes a series of fundamental books on scientific and methodological problems of information security, including those parts of cryptology that are already included in the university mathematical curriculum. The book by O. A. Logachev, A. A. Salnikov, and V. V. Yashchenko “Boolean functions in coding theory and cryptology” belongs to this series. It is written by mathematicians-cryptographers for mathematicians and presents in a systematic way certain results in one branch of cryptology: application of Boolean functions in the analysis and design of ciphers. The book is recommended to readers with basic university knowledge, namely students and graduate students in mathematics, research mathematicians, and cryptographers. Rector of MGU, Academician V. A. Sadovnichii February, 2004 vii Preface The notion of Boolean function was introduced in the second half of the 19th century in connection with investigations in mathematical logic and foundations of mathematics. Boolean functions are named after George Boole (1815–1864), an English mathematician, one of the founders of mathematical logic. In the first half of the 20th century Boolean functions attain fundamental importance in the foundations of mathematics. However, for a long time Boolean functions have not been used in applications. This situation changed drastically in the middle of the 20th century, when the intensive development of communication technology, instrument-building, and computer technology required the creation of an adequate mathematical apparatus. In this period, applied parts of mathematics such as the theory of finite functional systems, information theory, coding theory, and finally mathematical cryptography have been developed. The practice showed the fruitfulness of the application of Boolean functions to the problems of analysis and synthesis of discrete devices for processing and transformation of information. The concept of cryptography that has been established in the scientific liter- ature includes a range of scientific areas, each of them having its own subject of investigations
Load more

Recommended publications
  • The Missing Difference Problem, and Its Applications to Counter Mode
    The Missing Difference Problem, and its Applications to Counter Mode Encryption? Ga¨etanLeurent and Ferdinand Sibleyras Inria, France fgaetan.leurent,[email protected] Abstract. The counter mode (CTR) is a simple, efficient and widely used encryption mode using a block cipher. It comes with a security proof that guarantees no attacks up to the birthday bound (i.e. as long as the number of encrypted blocks σ satisfies σ 2n=2), and a matching attack that can distinguish plaintext/ciphertext pairs from random using about 2n=2 blocks of data. The main goal of this paper is to study attacks against the counter mode beyond this simple distinguisher. We focus on message recovery attacks, with realistic assumptions about the capabilities of an adversary, and evaluate the full time complexity of the attacks rather than just the query complexity. Our main result is an attack to recover a block of message with complexity O~(2n=2). This shows that the actual security of CTR is similar to that of CBC, where collision attacks are well known to reveal information about the message. To achieve this result, we study a simple algorithmic problem related to the security of the CTR mode: the missing difference problem. We give efficient algorithms for this problem in two practically relevant cases: where the missing difference is known to be in some linear subspace, and when the amount of data is higher than strictly required. As a further application, we show that the second algorithm can also be used to break some polynomial MACs such as GMAC and Poly1305, with a universal forgery attack with complexity O~(22n=3).
    [Show full text]
  • Linear-XOR and Additive Checksums Don't Protect Damgård-Merkle
    Linear-XOR and Additive Checksums Don’t Protect Damg˚ard-Merkle Hashes from Generic Attacks Praveen Gauravaram1! and John Kelsey2 1 Technical University of Denmark (DTU), Denmark Queensland University of Technology (QUT), Australia. [email protected] 2 National Institute of Standards and Technology (NIST), USA [email protected] Abstract. We consider the security of Damg˚ard-Merkle variants which compute linear-XOR or additive checksums over message blocks, inter- mediate hash values, or both, and process these checksums in computing the final hash value. We show that these Damg˚ard-Merkle variants gain almost no security against generic attacks such as the long-message sec- ond preimage attacks of [10,21] and the herding attack of [9]. 1 Introduction The Damg˚ard-Merkle construction [3, 14] (DM construction in the rest of this article) provides a blueprint for building a cryptographic hash function, given a fixed-length input compression function; this blueprint is followed for nearly all widely-used hash functions. However, the past few years have seen two kinds of surprising results on hash functions, that have led to a flurry of research: 1. Generic attacks apply to the DM construction directly, and make few or no assumptions about the compression function. These attacks involve attacking a t-bit hash function with more than 2t/2 work, in order to violate some property other than collision resistance. Exam- ples of generic attacks are Joux multicollision [8], long-message second preimage attacks [10,21] and herding attack [9]. 2. Cryptanalytic attacks apply to the compression function of the hash function.
    [Show full text]
  • On Hash Functions Using Checksums
    Downloaded from orbit.dtu.dk on: Sep 27, 2021 On hash functions using checksums Gauravaram, Praveen; Kelsey, John; Knudsen, Lars Ramkilde; Thomsen, Søren Steffen Publication date: 2008 Document Version Early version, also known as pre-print Link back to DTU Orbit Citation (APA): Gauravaram, P., Kelsey, J., Knudsen, L. R., & Thomsen, S. S. (2008). On hash functions using checksums. MAT report No. 2008-06 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. On hash functions using checksums ⋆ Praveen Gauravaram1⋆⋆, John Kelsey2, Lars Knudsen1, and Søren Thomsen1⋆ ⋆ ⋆ 1 DTU Mathematics, Technical University of Denmark, Denmark [email protected],[email protected],[email protected] 2 National Institute of Standards and Technology (NIST), USA [email protected] Abstract. We analyse the security of iterated hash functions that compute an input dependent check- sum which is processed as part of the hash computation.
    [Show full text]
  • Algebraic Cryptanalysis of GOST Encryption Algorithm
    Journal of Computer and Communications, 2014, 2, 10-17 Published Online March 2014 in SciRes. http://www.scirp.org/journal/jcc http://dx.doi.org/10.4236/jcc.2014.24002 Algebraic Cryptanalysis of GOST Encryption Algorithm Ludmila Babenko, Ekaterina Maro Department of Information Security, Southern Federal University, Taganrog, Russia Email: [email protected] Received October 2013 Abstract This paper observes approaches to algebraic analysis of GOST 28147-89 encryption algorithm (also known as simply GOST), which is the basis of most secure information systems in Russia. The general idea of algebraic analysis is based on the representation of initial encryption algorithm as a system of multivariate quadratic equations, which define relations between a secret key and a cipher text. Extended linearization method is evaluated as a method for solving the nonlinear sys- tem of equations. Keywords Encryption Algorithm GOST; GOST⊕; S-Box; Systems of Multivariate Quadratic Equations; Algebraic Cryptanalysis; Extended Linearization Method; Gaussian Elimination 1. Introduction The general idea of algebraic cryptanalysis is finding equations that describe nonlinear transformations of S- boxes followed by finding solution of these equations and obtaining the secret key. This method of cryptanalysis belongs to the class of attacks with known plaintext. It is enough to have a single plaintext/ciphertext pair for the success. Algebraic methods of cryptanalysis contain the following stages: • Creation of the system of equations that describe transformations in non-linear cryptographic primitives of the analyzed cipher (i.e., S-boxes for most symmetric ciphers); • Finding solution of this system. The idea to describe an encryption algorithm as system of linear equations originated quite long time ago.
    [Show full text]
  • GOST R 34.12-2015: Block Cipher "Magma"
    Stream: Independent Submission RFC: 8891 Updates: 5830 Category: Informational Published: September 2020 ISSN: 2070-1721 Authors: V. Dolmatov, Ed. D. Baryshkov JSC "NPK Kryptonite" Auriga, Inc. RFC 8891 GOST R 34.12-2015: Block Cipher "Magma" Abstract In addition to a new cipher with a block length of n=128 bits (referred to as "Kuznyechik" and described in RFC 7801), Russian Federal standard GOST R 34.12-2015 includes an updated version of the block cipher with a block length of n=64 bits and key length of k=256 bits, which is also referred to as "Magma". The algorithm is an updated version of an older block cipher with a block length of n=64 bits described in GOST 28147-89 (RFC 5830). This document is intended to be a source of information about the updated version of the 64-bit cipher. It may facilitate the use of the block cipher in Internet applications by providing information for developers and users of the GOST 64-bit cipher with the revised version of the cipher for encryption and decryption. Status of This Memo This document is not an Internet Standards Track specification; it is published for informational purposes. This is a contribution to the RFC Series, independently of any other RFC stream. The RFC Editor has chosen to publish this document at its discretion and makes no statement about its value for implementation or deployment. Documents approved for publication by the RFC Editor are not candidates for any level of Internet Standard; see Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8891.
    [Show full text]
  • GCM, GHASH and Weak Keys
    GCM, GHASH and Weak Keys Markku-Juhani O. Saarinen REVERE SECURITY 4500 Westgrove Drive, Suite 335, Addison, TX 75001, USA. [email protected] Abstract. The Galois/Counter Mode (GCM) of operation has been standardized by NIST to provide single-pass authenticated encryption. The GHASH authen- tication component of GCM belongs to a class of Wegman-Carter polynomial universal hashes that operate in the field GF (2128). GCM uses the same block cipher key K to both encrypt data and to derive the generator H of the authen- tication polynomial. In present literature, only the trivial weak key H = 0 has been considered. In this note we show that GHASH has much wider classes of weak keys in its 512 multiplicative subgroups, analyze some of their properties, and give experimental results when GCM is used with the AES algorithm. Keywords: Cryptanalysis, Galois/Counter Mode, AES-GCM, Weak Keys. 1 Introduction Authenticated encryption modes and algorithms provide confidentiality and in- tegrity protection in a single processing step. This results in performance and cost advantages as data paths can be shared. The Galois/Counter Mode (GCM) has been standardized by NIST [9] to be used in conjunction with a 128-bit block cipher for providing authenticated en- cryption functionality. When paired with the AES [10] algorithm, the resulting AES-GCM combination has been used as a replacement to dedicated hash-based HMAC [1] in popular cryptographic protocols such as SSH [4], IPSec [6] and TLS [12]. In AES-GCM, data is encrypted using the Counter Mode (CTR). A single AES key K is used to both encrypt data and to derive authentication secrets.
    [Show full text]
  • Algebraic Complexity Reduction and Cryptanalysis of GOST Nicolas T
    Algebraic Complexity Reduction and Cryptanalysis of GOST Nicolas T. Courtois University College London, Gower Street, London, UK Abstract. GOST 28147-89 is a well-known Russian government encryp- tion standard. Its large key size of 256 bits at a particularly low imple- mentation cost [83] make that it is widely implemented and used [70, 105, 66, 83, 88]. In 2010 GOST was submitted to ISO to become an inter- national standard. GOST was analysed by Schneier, Biham, Biryukov, Dunkelman, Wagner, various Australian, Japanese, and Russian scien- tists, and all researchers seemed to agree that it looks quite secure. Though the internal structure of GOST seems quite weak compared to DES, and in particular the diffusion is not quite as good, it is always stip- ulated that this should be compensated by a large number of 32 rounds cf. [63, 101, 100, 8] and by the additional non-linearity and diffusion pro- vided by modular additions [63, 84]. At Crypto 2008 the hash function based on this cipher was broken. Yet as far as traditional encryption ap- plications with keys generated at random are concerned, until 2011 no cryptographically significant attack on GOST was found. In this paper we present several new attacks on full 32-rounds GOST. Our methodology is derived from the idea of conditional algebraic attacks on block ciphers [25, 20] which can be defined as attacks in which the prob- lem of key recovery is written as a problem of solving a large system of algebraic equations, and where the attacker makes some \clever" as- sumptions on the cipher which lead to an important simplification in the algebraic description of the problem, which makes it solvable in practice if the assumptions hold.
    [Show full text]
  • Conjunctively Polynomial–Like Boolean Functions and the Maximal Closed Classes
    Annales Univ. Sci. Budapest., Sect. Comp. 32 (2010) 49-61 CONJUNCTIVELY POLYNOMIAL{LIKE BOOLEAN FUNCTIONS AND THE MAXIMAL CLOSED CLASSES J. Gonda (Budapest, Hungary) Abstract. In [7] it was introduced the notion of the conjunctively polynomial like Boolean functions. In this article it is investigated how these functions are related to the maximal closed classes of the Boolean functions and it is pointed out that there are bases of the Boolean functions containing only conjunctively polynomial-like Boolean functions. In this article disjunction and logical sum, conjunction and logical product, exclusive or and modulo two sum, as well as complementation and negation are used in the same sense and they are denoted respectively by +; ¢ (or simply without any operation sign), © and ¹. The elements of the ¯eld with two elements and the elements of the Boolean algebra with two elements are denoted by the same signs, namely by 0 and 1; N denotes the non-negative integers, and N+ the positive ones. 1. Introduction Logical functions and especially the two-valued ones have important roles in our everyday life, so it is easy to understand why they are widely investigated. A scope of investigations is the representations of these functions and the transforms from one representation to another ([3], [4], [5], [8]). Another area of the examinations is the search of special classes of the set of the functions. Post determined the closed classes of the switching functions [9], but there are a lot of another classes of the Boolean functions invariant with respect to some Mathematics Subject Classi¯cation: 06E30, 94C10, 15A18 50 J.
    [Show full text]
  • Composition of Post Classes and Normal Forms of Boolean Functions Miguel Couceiroa,1, Stephan Foldesb, Erkko Lehtonenb,∗
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Discrete Mathematics 306 (2006) 3223–3243 www.elsevier.com/locate/disc Composition of Post classes and normal forms of Boolean functions Miguel Couceiroa,1, Stephan Foldesb, Erkko Lehtonenb,∗ aDepartment of Mathematics, Statistics and Philosophy, University of Tampere, FI-33014 Tampereen yliopisto, Finland bInstitute of Mathematics, Tampere University of Technology, P.O. Box 553, FI-33101 Tampere, Finland Received 23 March 2005; received in revised form 12 May 2006; accepted 25 June 2006 Available online 6 September 2006 Abstract The class composition C◦K of Boolean clones, being the set of composite functions f(g1,...,gn) with f ∈ C, g1,...,gn ∈ K, is investigated. This composition C ◦ K is either the join C ∨ K in the Post Lattice or it is not a clone, and all pairs of clones C, K are classified accordingly. Factorizations of the clone of all Boolean functions as a composition of minimal clones are described and seen to correspond to normal form representations of Boolean functions. The median normal form, arising from the factorization of with the clone SM of self-dual monotone functions as the leftmost composition factor, is compared in terms of complexity with the well-known DNF, CNF, and Zhegalkin (Reed–Muller) polynomial representations, and it is shown to provide a more efficient normal form representation. © 2006 Elsevier B.V. All rights reserved. MSC: 06E30; 08A70 Keywords: Function class composition; Clones; Boolean functions; Post classes; Class factorization; Normal forms; DNF; CNF; Zhegalkin polynomial; Reed–Muller polynomial; Formulas; Efficient representations; Complexity; Median; Ternary majority 1.
    [Show full text]
  • Gene Ontology Mining Tool Gost Master’S Thesis
    UNIVERSITY OF TARTU Faculty of Mathematics and Computer Science Institute of Computer Science Jüri Reimand Gene Ontology mining tool GOSt Master’s Thesis Supervisor: Jaak Vilo, PhD TARTU 2006 Contents Introduction 1 1 Gene Ontology (GO) 3 1.1 Biologicalbackground . 3 1.2 Ontologydesignandimplementation. 4 1.3 ThreeontologiesofGO.. .. .. .. .. .. .. 5 1.4 Geneannotations .......................... 8 1.5 Biologicalpathways. 11 1.6 PathwaydatabasesandintegrationwithGO . 13 1.7 ApplicationofGO:Geneexpressionanalysis . 15 2 GOSt - Gene Ontology Statistics 20 2.1 GeneOntologyrepresentation . 20 2.2 AnnotationsandTruePathRule . 22 2.3 Annotationsetsandquerying . 23 2.4 Rankingresults ........................... 24 2.4.1 Precisionandrecall. 25 2.4.2 Statisticalsignificance . 27 2.4.3 Hypergeometric probability. Fisher’s exact test . ... 28 2.4.4 Multipletesting. 30 2.5 Simulationofsignificancethresholds. 32 2.5.1 Experimentalapproach . 32 2.5.2 Analyticalapproach . 37 3 Mining GO with GOSt 42 3.1 Simple queries. Method GOSTMINER1 ............ 42 3.2 Ordered queries. Method GOSTMINER2 ............ 43 3.3 Approximationofprobabilityfunction . 45 i 3.4 Ordered queries. Method GOSTMINER3 ............ 47 3.5 Significant subgraphs. Method GOSTMINER4 ......... 50 4 The tool GOSt: usage and features 54 4.1 Generalusage............................ 54 4.2 Graphicaluserinterface. Evidencecodes. .. 56 4.3 Visualisationofmatchingterms . 58 4.4 Orderedqueriesanalysis . 59 4.5 Expressiondataanalysispipeline . 59 Summary 63 Summary (in Estonian) 65 Acknowledgements 67 Bibliography 68 ii Introduction Recent advancements in technology have changed research course of molecu- lar biology. Fully sequenced genomes of versatile organisms become available at great pace. A modern biologist no longer needs to concentrate on a single gene. High-thoughput technologies such as microarrays produce groups with hundreds of interesting genes proven similar in some sense.
    [Show full text]
  • Pycryptodome Documentation Release 3.10.4
    PyCryptodome Documentation Release 3.10.4 Legrandin Sep 24, 2021 Contents 1 PyCryptodome 3 2 Features 5 3 Installation 9 3.1 Compiling in Linux Ubuntu.......................................9 3.2 Compiling in Linux Fedora....................................... 10 3.3 Windows (from sources, Python 2.7).................................. 10 3.4 Windows (from sources, Python 3.5 and newer)............................. 11 3.5 Documentation.............................................. 12 3.6 PGP verification............................................. 12 4 Compatibility with PyCrypto 15 5 API documentation 17 5.1 Crypto.Cipher package....................................... 17 5.1.1 Introduction........................................... 17 5.1.2 API principles.......................................... 17 5.1.3 Symmetric ciphers....................................... 18 5.1.4 Legacy ciphers......................................... 34 5.2 Crypto.Signature package..................................... 34 5.2.1 Signing a message....................................... 34 5.2.2 Verifying a signature...................................... 35 5.2.3 Available mechanisms..................................... 35 5.3 Crypto.Hash package......................................... 35 5.3.1 API principles.......................................... 35 5.3.2 Attributes of hash objects.................................... 37 5.3.3 Modern hash algorithms.................................... 37 5.3.4 Extensible-Output Functions (XOF).............................. 38 5.3.5
    [Show full text]
  • Understanding How to Prevent Sensitive Data Exposure
    Understanding how to prevent Sensitive Data Exposure Dr Simon Greatrix Just Trust The Internet! • Lots of free advice • Opinions to suit all tastes • Also has pictures of cats! • Not responsible for the collapse of civilization (so far) • Google has excellent branding Top tips for a successful presentation! (according to the internet) • Start with a joke • Imagine the audience naked • Avoid showing emotion • Use images to jazz things up Obligatory famous historical data breaches ● 200,000 BCE to 6000 BCE : Tribal life with no privacy at all ● 600 BCE to 400CE: Ancient City culture view privacy as a bad thing ● 75 CE to 800 CE: There is no word for “privacy” in classical nor medieval“Where Latin people conceal their ways from one another … ● 1215 CE:there Fourth no Council one will Of ever Lateran rightly makes gain neitherconfession their mandatory due honour nor office nor the justice that is befitting” ● 1450 CE: First use of “privacy” in English. Socrates (470 to 399 BCE) ● 1700 CE: Solo beds ● 1890 CE: First use of “Right To Privacy” What are we actually expected to do? ● The Standards – OWASP – PCI-DSS ● The Tools – Ciphers – Hashes An aside: What is “strong encryption”? Source: https://www.keylength.com Is this really a good idea? https://xkcd.com/538/ Your Personal Information Please don’t send us your personal information. We do not want your personal information. We have a hard enough time keeping track of our own personal information, let alone yours. If you tell us your name, or any identifying information, we will forget it immediately.
    [Show full text]