Bits and Bit Sequences Integers
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Hamming Weight Attacks on Cryptographic Hardware – Breaking Masking Defense?
Hamming Weight Attacks on Cryptographic Hardware { Breaking Masking Defense? Marcin Gomu lkiewicz1 and Miros law Kuty lowski12 1 Cryptology Centre, Poznan´ University 2 Institute of Mathematics, Wroc law University of Technology, ul. Wybrzeze_ Wyspianskiego´ 27 50-370 Wroc law, Poland Abstract. It is believed that masking is an effective countermeasure against power analysis attacks: before a certain operation involving a key is performed in a cryptographic chip, the input to this operation is com- bined with a random value. This has to prevent leaking information since the input to the operation is random. We show that this belief might be wrong. We present a Hamming weight attack on an addition operation. It works with random inputs to the addition circuit, hence masking even helps in the case when we cannot control the plaintext. It can be applied to any round of the encryption. Even with moderate accuracy of measuring power consumption it de- termines explicitly subkey bits. The attack combines the classical power analysis (over Hamming weight) with the strategy of the saturation at- tack performed using a random sample. We conclude that implementing addition in cryptographic devices must be done very carefully as it might leak secret keys used for encryption. In particular, the simple key schedule of certain algorithms (such as IDEA and Twofish) combined with the usage of addition might be a serious danger. Keywords: cryptographic hardware, side channel cryptanalysis, Ham- ming weight, power analysis 1 Introduction Symmetric encryption algorithms are often used to protect data stored in inse- cure locations such as hard disks, archive copies, and so on. -
Type I Codes Over GF(4)
Type I Codes over GF(4) Hyun Kwang Kim¤ San 31, Hyoja Dong Department of Mathematics Pohang University of Science and Technology Pohang, 790-784, Korea e-mail: [email protected] Dae Kyu Kim School of Electronics & Information Engineering Chonbuk National University Chonju, Chonbuk 561-756, Korea e-mail: [email protected] Jon-Lark Kimy Department of Mathematics University of Louisville Louisville, KY 40292, USA e-mail: [email protected] Abstract It was shown by Gaborit el al. [10] that a Euclidean self-dual code over GF (4) with the property that there is a codeword whose Lee weight ´ 2 (mod 4) is of interest because of its connection to a binary singly-even self-dual code. Such a self-dual code over GF (4) is called Type I. The purpose of this paper is to classify all Type I codes of lengths up to 10 and extremal Type I codes of length 12, and to construct many new extremal Type I codes over GF (4) of ¤The present study was supported by Com2MaC-KOSEF, POSTECH BSRI research fund, and grant No. R01-2006-000-11176-0 from the Basic Research Program of the Korea Science & Engineering Foundation. ycorresponding author, supported in part by a Project Completion Grant from the University of Louisville. 1 lengths from 14 to 22 and 34. As a byproduct, we construct a new extremal singly-even self-dual binary [36; 18; 8] code, and a new ex- tremal singly-even self-dual binary [68; 34; 12] code with a previously unknown weight enumerator W2 for ¯ = 95 and γ = 1. -
Arxiv:1311.6244V1 [Physics.Comp-Ph] 25 Nov 2013
An efficient implementation of Slater-Condon rules Anthony Scemama,∗ Emmanuel Giner November 26, 2013 Abstract Slater-Condon rules are at the heart of any quantum chemistry method as they allow to simplify 3N- dimensional integrals as sums of 3- or 6-dimensional integrals. In this paper, we propose an efficient implementation of those rules in order to identify very rapidly which integrals are involved in a matrix ele- ment expressed in the determinant basis set. This implementation takes advantage of the bit manipulation instructions on x86 architectures that were introduced in 2008 with the SSE4.2 instruction set. Finding which spin-orbitals are involved in the calculation of a matrix element doesn't depend on the number of electrons of the system. In this work we consider wave functions Ψ ex- For two determinants which differ by two spin- pressed as linear combinations of Slater determinants orbitals: D of orthonormal spin-orbitals φ(r): jl hDjO1jDiki = 0 (4) X Ψ = c D (1) jl i i hDjO2jDiki = hφiφkjO2jφjφli − hφiφkjO2jφlφji i All other matrix elements involving determinants Using the Slater-Condon rules,[1, 2] the matrix ele- with more than two substitutions are zero. ments of any one-body (O1) or two-body (O2) oper- An efficient implementation of those rules requires: ator expressed in the determinant space have simple expressions involving one- and two-electron integrals 1. to find the number of spin-orbital substitutions in the spin-orbital space. The diagonal elements are between two determinants given by: 2. to find which spin-orbitals are involved in the X substitution hDjO1jDi = hφijO1jφii (2) i2D 3. -
Bash Guide for Beginners
Bash Guide for Beginners Machtelt Garrels Garrels BVBA <tille wants no spam _at_ garrels dot be> Version 1.11 Last updated 20081227 Edition Bash Guide for Beginners Table of Contents Introduction.........................................................................................................................................................1 1. Why this guide?...................................................................................................................................1 2. Who should read this book?.................................................................................................................1 3. New versions, translations and availability.........................................................................................2 4. Revision History..................................................................................................................................2 5. Contributions.......................................................................................................................................3 6. Feedback..............................................................................................................................................3 7. Copyright information.........................................................................................................................3 8. What do you need?...............................................................................................................................4 9. Conventions used in this -
L#07: PHP Date & Time
L#07: PHP Date & Time Using Date & Time in PHP Lecture 7 March 21, 2007 ©2007, I.Sarah Al-Shareef 1 Table of Content Overview Date and Time Functions Definitions Displaying Date and Time Getting Date as Timestamp Displaying Readable Date Building Formatting String Special Formatting Characters for date() Convert from Readable to Timestamp Getting Files Dates Displaying Dates in other languages Formatting Characters for strftime() March 21, 2007 ©2007, I.Sarah Al-Shareef 2 1 L#07: PHP Date & Time Overview Date & Time Functions Function Description checkdate() Validates set of Gregorian year, month, and day values (for example, 2005, 3, 17). date_sunrise() Returns time of sunrise for a given day and location (new in PHP 5). date_sunset() Returns time of sunset for a given day and location (new in PHP 5). date() Formats a local date/time, given a Unix timestamp (for example, 1111035030000 from the introduction to this chapter) and a formatting string. getdate() Given a Unix timestamp, returns an associative array containing date and time information (defaults to current time). gettimeofday() Returns an associative array containing information about the current system time. In PHP 5.1, it is possible for this function to return a float as well. March 21, 2007 ©2007, I.Sarah Al-Shareef 3 Overview Date & Time Fun cont. Function Description gmdate() Formats a GMT/UTC date/time. Uses the same formatting characters as the date() function. gmmktime() Converts a set of GMT date/time values into a Unix timestamp (analogous to mktime()). gmstrftime() Formats a GMT/UTC date/time according to locale settings (similar to strftime() except the time used is GMT/UTC). -
Faster Population Counts Using AVX2 Instructions
Faster Population Counts Using AVX2 Instructions Wojciech Mula,Nathan Kurz and Daniel Lemire∗ ?Universit´edu Qu´ebec (TELUQ), Canada Email: [email protected] Counting the number of ones in a binary stream is a common operation in database, information-retrieval, cryptographic and machine-learning applications. Most processors have dedicated instructions to count the number of ones in a word (e.g., popcnt on x64 processors). Maybe surprisingly, we show that a vectorized approach using SIMD instructions can be twice as fast as using the dedicated instructions on recent Intel processors. The benefits can be even greater for applications such as similarity measures (e.g., the Jaccard index) that require additional Boolean operations. Our approach has been adopted by LLVM: it is used by its popular C compiler (Clang). Keywords: Software Performance; SIMD Instructions; Vectorization; Bitset; Jaccard Index 1. INTRODUCTION phy [5], e.g., as part of randomness tests [6] or to generate pseudo-random permutations [7]. They can help find We can represent all sets of integers in f0; 1;:::; 63g duplicated web pages [8]. They are frequently used in using a single 64-bit word. For example, the word 0xAA bioinformatics [9, 10, 11], ecology [12], chemistry [13], (0b10101010) represents the set f1; 3; 5; 7g. Intersections and so forth. Gueron and Krasnov use population-count and unions between such sets can be computed using instructions as part of a fast sorting algorithm [14]. a single bitwise logical operation on each pair of words The computation of the population count is so (AND, OR). We can generalize this idea to sets of important that commodity processors have dedicated integers in f0; 1; : : : ; n − 1g using dn=64e 64-bit words. -
A Novel High Speed Leading Zero Counter for Floating Point Units
Satish Paidi, Rohit Sreerama, K.Neelima / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 2,Mar-Apr 2012, pp.1103-1105 A Novel High Speed Leading Zero Counter For Floating Point Units Satish Paidi*, Rohit Sreerama*, K.Neelima** *(M.Tech VLSI, Sree Vidyanikethan Engineering College, Tirupathi,) ** (Assistant Professor, Sree Vidyanikethan Engineering College, Tirupathi,) ABSTRACT: - This paper mainly focuses on leading derived Boolean relations that describes the proposed zero counting. In this paper a novel leading zero counter leading zero counter. In section 4 the implementation is proposed. New Boolean expressions are derived for results and the comparison with the existing method are the new leading zero counter. We can explore various discussed and section 5 concludes the paper follows by designs of leading zero counting unit by using the the references. proposed approach. When compared with the known architectures the new circuits can be implemented II. FUNCTIONALITY OF EXISTING effectively in both static and dynamic logic and also LEADING ZERO COUNTING METHOD requires less energy per operation. The proposed leading This section discusses the method which is used in zero counter can also be integrated with a leading zero leading zero counting, their implementation and anticipation logic for better and fast results. Finally, a functionality. A leading zero is any zero bit that leads a simple and effective Leading Zero Counter was proposed number string in positional notation. In binary and the occupancy rate and the delay characteristics are representation consider the number of consecutive zeros investigated. that appear in a word before the first more significant bit Keywords - Floating Point Unit, Normalization, Leading that equal to one. -
Coding Theory and Applications Solved Exercises and Problems Of
Coding Theory and Applications Solved Exercises and Problems of Linear Codes Enes Pasalic University of Primorska Koper, 2013 Contents 1 Preface 3 2 Problems 4 2 1 Preface This is a collection of solved exercises and problems of linear codes for students who have a working knowledge of coding theory. Its aim is to achieve a balance among the computational skills, theory, and applications of cyclic codes, while keeping the level suitable for beginning students. The contents are arranged to permit enough flexibility to allow the presentation of a traditional introduction to the subject, or to allow a more applied course. Enes Pasalic [email protected] 3 2 Problems In these exercises we consider some basic concepts of coding theory, that is we introduce the redundancy in the information bits and consider the possible improvements in terms of improved error probability of correct decoding. 1. (Error probability): Consider a code of length six n = 6 defined as, (a1; a2; a3; a2 + a3; a1 + a3; a1 + a2) where ai 2 f0; 1g. Here a1; a2; a3 are information bits and the remaining bits are redundancy (parity) bits. Compute the probability that the decoder makes an incorrect decision if the bit error probability is p = 0:001. The decoder computes the following entities b1 + b3 + b4 = s1 b1 + b3 + b5 == s2 b1 + b2 + b6 = s3 where b = (b1; b2; : : : ; b6) is a received vector. We represent the error vector as e = (e1; e2; : : : ; e6) and clearly if a vector (a1; a2; a3; a2+ a3; a1 + a3; a1 + a2) was transmitted then b = a + e, where '+' denotes bitwise mod 2 addition. -
Leading One Prediction - Implementation, Generalization, and Application
LEADING ONE PREDICTION - IMPLEMENTATION, GENERALIZATION, AND APPLICATION Nhon Quach Michael J. Flynn Technical Report: CSL-TR-91-463 March 1991 This work was supported by NSF contract No. MlP88-22961. Leading One Prediction - Implementation, Generalization, and Application bY Nhon Quach and Michael Flynn Technical Report: CSL-TR-91-463 Masch 1991 Computer Systems Laboratory Departments of Electrical Engineering and Computer Science St anford University St anford, California 94305 Abstract This paper presents the concept of leading-one prediction (LOP) used in most high-speed floating-point adders in greater detail and describes two existing implementations. The first one is similar to that used in the TBM RS /GO00 processor. The second is a distributed version of the first, con- suming less hardware when multiple patterns need to be detected. We show how to modify these circuits for sign-magnitude numbers as dictated by the IEEE standard. We then point out that (1) LOP and carry lookahead in parallel addition belong to the same class of problem, that of bit pattern detection. Such a recognition allows techniques developed for parallel addition to be borrowed for bit pattern detection. And (2) LOP can be applied to compute the sticky bit needed for binary multipliers to perform IEEE rounding. Key Words and Phrases: Lea,ding one prediction, high-speed floating- point adders, parallel addition, IEEE rounding, sticky bit computation, par- allel implementation. Copyright @ 1991 bY Nhon Quach and Michael Flynn Contents 1 Introduction 1 2 Leading One Prediction 2 2.1 Theory. ...................................... 2 2.2 Implementations ................................. 3 2.3 Modification for Sign-Magnitude Numbers .................. -
The C Programming Language
The C programming Language The C programming Language By Brian W. Kernighan and Dennis M. Ritchie. Published by Prentice-Hall in 1988 ISBN 0-13-110362-8 (paperback) ISBN 0-13-110370-9 Contents ● Preface ● Preface to the first edition ● Introduction 1. Chapter 1: A Tutorial Introduction 1. Getting Started 2. Variables and Arithmetic Expressions 3. The for statement 4. Symbolic Constants 5. Character Input and Output 1. File Copying 2. Character Counting 3. Line Counting 4. Word Counting 6. Arrays 7. Functions 8. Arguments - Call by Value 9. Character Arrays 10. External Variables and Scope 2. Chapter 2: Types, Operators and Expressions 1. Variable Names 2. Data Types and Sizes 3. Constants 4. Declarations http://freebooks.by.ru/view/CProgrammingLanguage/kandr.html (1 of 5) [5/15/2002 10:12:59 PM] The C programming Language 5. Arithmetic Operators 6. Relational and Logical Operators 7. Type Conversions 8. Increment and Decrement Operators 9. Bitwise Operators 10. Assignment Operators and Expressions 11. Conditional Expressions 12. Precedence and Order of Evaluation 3. Chapter 3: Control Flow 1. Statements and Blocks 2. If-Else 3. Else-If 4. Switch 5. Loops - While and For 6. Loops - Do-While 7. Break and Continue 8. Goto and labels 4. Chapter 4: Functions and Program Structure 1. Basics of Functions 2. Functions Returning Non-integers 3. External Variables 4. Scope Rules 5. Header Files 6. Static Variables 7. Register Variables 8. Block Structure 9. Initialization 10. Recursion 11. The C Preprocessor 1. File Inclusion 2. Macro Substitution 3. Conditional Inclusion 5. Chapter 5: Pointers and Arrays 1. -
Conversion of Mersenne Twister to Double-Precision Floating-Point
Conversion of Mersenne Twister to double-precision floating-point numbers Shin Harasea,∗ aCollege of Science and Engineering, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga, 525-8577, Japan. Abstract The 32-bit Mersenne Twister generator MT19937 is a widely used random number generator. To generate numbers with more than 32 bits in bit length, and particularly when converting into 53-bit double-precision floating-point numbers in [0, 1) in the IEEE 754 format, the typical implementation con- catenates two successive 32-bit integers and divides them by a power of 2. In this case, the 32-bit MT19937 is optimized in terms of its equidistribution properties (the so-called dimension of equidistribution with v-bit accuracy) under the assumption that one will mainly be using 32-bit output values, and hence the concatenation sometimes degrades the dimension of equidis- tribution compared with the simple use of 32-bit outputs. In this paper, we analyze such phenomena by investigating hidden F2-linear relations among the bits of high-dimensional outputs. Accordingly, we report that MT19937 with a specific lag set fails several statistical tests, such as the overlapping collision test, matrix rank test, and Hamming independence test. Keywords: Random number generation, Mersenne Twister, Equidistribution, Statistical test 2010 MSC: arXiv:1708.06018v4 [math.NA] 2 Sep 2018 65C10, 11K45 1. Introduction Random number generators (RNGs) (or more precisely, pseudorandom number generators) are an essential tool for scientific computing, especially ∗Corresponding author Email address: [email protected] (Shin Harase) Preprint submitted to Elsevier September 5, 2018 for Monte Carlo methods. -
Applications of Search Techniques to Cryptanalysis and the Construction of Cipher Components. James David Mclaughlin Submitted F
Applications of search techniques to cryptanalysis and the construction of cipher components. James David McLaughlin Submitted for the degree of Doctor of Philosophy (PhD) University of York Department of Computer Science September 2012 2 Abstract In this dissertation, we investigate the ways in which search techniques, and in particular metaheuristic search techniques, can be used in cryptology. We address the design of simple cryptographic components (Boolean functions), before moving on to more complex entities (S-boxes). The emphasis then shifts from the construction of cryptographic arte- facts to the related area of cryptanalysis, in which we first derive non-linear approximations to S-boxes more powerful than the existing linear approximations, and then exploit these in cryptanalytic attacks against the ciphers DES and Serpent. Contents 1 Introduction. 11 1.1 The Structure of this Thesis . 12 2 A brief history of cryptography and cryptanalysis. 14 3 Literature review 20 3.1 Information on various types of block cipher, and a brief description of the Data Encryption Standard. 20 3.1.1 Feistel ciphers . 21 3.1.2 Other types of block cipher . 23 3.1.3 Confusion and diffusion . 24 3.2 Linear cryptanalysis. 26 3.2.1 The attack. 27 3.3 Differential cryptanalysis. 35 3.3.1 The attack. 39 3.3.2 Variants of the differential cryptanalytic attack . 44 3.4 Stream ciphers based on linear feedback shift registers . 48 3.5 A brief introduction to metaheuristics . 52 3.5.1 Hill-climbing . 55 3.5.2 Simulated annealing . 57 3.5.3 Memetic algorithms . 58 3.5.4 Ant algorithms .