Melissa Martinez the Code Book by Simon Singh
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CS 105 Review Questions #2 in Addition to These Questions
1 CS 105 Review Questions #2 In addition to these questions, remember to look over your labs, homework assignments, readings in the book and your notes. 1. Explain how writing functions inside a Python program can potentially make the program more concise (i.e. take up fewer total lines of code). 2. The following Python statement may cause a ZeroDivisionError. Rewrite the code so that the program will not automatically halt if this error occurs. c = a / b 3. Indicate whether each statement is true or false. a. In ASCII code, the values corresponding to letters in the alphabet are consecutive. b. ASCII code uses the same values for lowercase letters as it does for capital letters. c. In ASCII code, non-printing, invisible characters all have value 0 4. Properties of ASCII representation: a. Each character is stored as how much information? b. If the ASCII code for ‘A’ is 65, then the ASCII code for ‘M’ should be ______. c. Suppose that the hexadecimal ASCII code for the lowercase letter ‘a’ is 0x61. Which lowercase letter would have the hexadecimal ASCII code 0x71 ? d. If we represent the sentence “The cat slept.” in ASCII code (not including the quotation marks), how many bytes does this require? e. How does Unicode differ from ASCII? 5. Estimate the size of the following file. It contains a 500-page book, where a typical page has 2000 characters of ASCII text and one indexed-color image measuring 200x300 pixels. “Indexed color” means that each pixel of an image takes up one byte. -
June 2014 Society Meetings Society and Events SHEPHARD PRIZE: NEW PRIZE Meetings for MATHEMATICS 2014 and Events Following a Very Generous Tions Open in Late 2014
LONDONLONDON MATHEMATICALMATHEMATICAL SOCIETYSOCIETY NEWSLETTER No. 437 June 2014 Society Meetings Society and Events SHEPHARD PRIZE: NEW PRIZE Meetings FOR MATHEMATICS 2014 and Events Following a very generous tions open in late 2014. The prize Monday 16 June donation made by Professor may be awarded to either a single Midlands Regional Meeting, Loughborough Geoffrey Shephard, the London winner or jointly to collaborators. page 11 Mathematical Society will, in 2015, The mathematical contribution Friday 4 July introduce a new prize. The prize, to which an award will be made Graduate Student to be known as the Shephard must be published, though there Meeting, Prize will be awarded bienni- is no requirement that the pub- London ally. The award will be made to lication be in an LMS-published page 8 a mathematician (or mathemati- journal. Friday 4 July cians) based in the UK in recog- Professor Shephard himself is 1 Society Meeting nition of a specific contribution Professor of Mathematics at the Hardy Lecture to mathematics with a strong University of East Anglia whose London intuitive component which can be main fields of interest are in page 9 explained to those with little or convex geometry and tessella- Wednesday 9 July no knowledge of university math- tions. Professor Shephard is one LMS Popular Lectures ematics, though the work itself of the longest-standing members London may involve more advanced ideas. of the LMS, having given more page 17 The Society now actively en- than sixty years of membership. Tuesday 19 August courages members to consider The Society wishes to place on LMS Meeting and Reception nominees who could be put record its thanks for his support ICM 2014, Seoul forward for the award of a in the establishment of the new page 11 Shephard Prize when nomina- prize. -
COS433/Math 473: Cryptography Mark Zhandry Princeton University Spring 2017 Cryptography Is Everywhere a Long & Rich History
COS433/Math 473: Cryptography Mark Zhandry Princeton University Spring 2017 Cryptography Is Everywhere A Long & Rich History Examples: • ~50 B.C. – Caesar Cipher • 1587 – Babington Plot • WWI – Zimmermann Telegram • WWII – Enigma • 1976/77 – Public Key Cryptography • 1990’s – Widespread adoption on the Internet Increasingly Important COS 433 Practice Theory Inherent to the study of crypto • Working knowledge of fundamentals is crucial • Cannot discern security by experimentation • Proofs, reductions, probability are necessary COS 433 What you should expect to learn: • Foundations and principles of modern cryptography • Core building blocks • Applications Bonus: • Debunking some Hollywood crypto • Better understanding of crypto news COS 433 What you will not learn: • Hacking • Crypto implementations • How to design secure systems • Viruses, worms, buffer overflows, etc Administrivia Course Information Instructor: Mark Zhandry (mzhandry@p) TA: Fermi Ma (fermima1@g) Lectures: MW 1:30-2:50pm Webpage: cs.princeton.edu/~mzhandry/2017-Spring-COS433/ Office Hours: please fill out Doodle poll Piazza piaZZa.com/princeton/spring2017/cos433mat473_s2017 Main channel of communication • Course announcements • Discuss homework problems with other students • Find study groups • Ask content questions to instructors, other students Prerequisites • Ability to read and write mathematical proofs • Familiarity with algorithms, analyZing running time, proving correctness, O notation • Basic probability (random variables, expectation) Helpful: • Familiarity with NP-Completeness, reductions • Basic number theory (modular arithmetic, etc) Reading No required text Computer Science/Mathematics Chapman & Hall/CRC If you want a text to follow along with: Second CRYPTOGRAPHY AND NETWORK SECURITY Cryptography is ubiquitous and plays a key role in ensuring data secrecy and Edition integrity as well as in securing computer systems more broadly. -
Issn: 2278-6244 New Approach of Arabic Encryption/Decryption Technique Using Vigenere Cipher on Mod 39
International Journal of Advanced Research in IT and Engineering ISSN: 2278-6244 NEW APPROACH OF ARABIC ENCRYPTION/DECRYPTION TECHNIQUE USING VIGENERE CIPHER ON MOD 39 Yahya Alqahtani* Prakash Kuppuswamy* Sikandhar Shah* Abstract: The cryptographic methods for enhancing the security of digital contents have gained high significance in the current era. This paper sets out to contribute to the general body of knowledge in the area of classical cryptography by developing a new way of Arabic encryption using Arabic plaintext. The new innovation idea discusses modification of Vigenère cipher which works by adding a key repeatedly into the plaintext using the ,and 28 assigned to blank space and =29 27 = ي , . ,1 =ب ,0 = أ convention that and addition is carried out modulo 39 that is, if the result is greater than 39, we ;38=٩…30= subtract as many multiples of 39 as are needed to bring us into the range [0, . , 38], that is, ,The paper has the following structure: section II consist of related works .[٩ , . ,أ] section III of the methodology, section IV The algorithm section V Implementation, section VI Results and Analysis and section VII concluded the paper. Keywords: Caesar cipher, Vigenere cipher, modulation, symmetric key, Plain text, Cipher text. *Lecturer, Department of Computer Engineering & Networks, Jazan University, Jazan, KSA. Vol. 2 | No. 12 | December 2013 www.garph.co.uk IJARIE | 1 International Journal of Advanced Research in IT and Engineering ISSN: 2278-6244 I INTRODUCTION Cryptology has existed for more than 2000 years. But, what is cryptology? The word cryptology is derived from two Greek words: kryptos, which means "hidden or secret," and logos, which means, "description." Cryptology means secret speech or communication. -
Battle Management Language: History, Employment and NATO Technical Activities
Battle Management Language: History, Employment and NATO Technical Activities Mr. Kevin Galvin Quintec Mountbatten House, Basing View, Basingstoke Hampshire, RG21 4HJ UNITED KINGDOM [email protected] ABSTRACT This paper is one of a coordinated set prepared for a NATO Modelling and Simulation Group Lecture Series in Command and Control – Simulation Interoperability (C2SIM). This paper provides an introduction to the concept and historical use and employment of Battle Management Language as they have developed, and the technical activities that were started to achieve interoperability between digitised command and control and simulation systems. 1.0 INTRODUCTION This paper provides a background to the historical employment and implementation of Battle Management Languages (BML) and the challenges that face the military forces today as they deploy digitised C2 systems and have increasingly used simulation tools to both stimulate the training of commanders and their staffs at all echelons of command. The specific areas covered within this section include the following: • The current problem space. • Historical background to the development and employment of Battle Management Languages (BML) as technology evolved to communicate within military organisations. • The challenges that NATO and nations face in C2SIM interoperation. • Strategy and Policy Statements on interoperability between C2 and simulation systems. • NATO technical activities that have been instigated to examine C2Sim interoperation. 2.0 CURRENT PROBLEM SPACE “Linking sensors, decision makers and weapon systems so that information can be translated into synchronised and overwhelming military effect at optimum tempo” (Lt Gen Sir Robert Fulton, Deputy Chief of Defence Staff, 29th May 2002) Although General Fulton made that statement in 2002 at a time when the concept of network enabled operations was being formulated by the UK and within other nations, the requirement remains extant. -
JPBM Communications Award Is Given to He Takes a Particular Interest in Problems That Lie Ian Stewart of the University of Warwick
comm-jpbm.qxp 3/5/99 3:49 PM Page 568 JPBM Awards Presented in San Antonio The Joint Policy Board for Mathematics (JPBM) The sheer volume of this work is staggering, but Communications Award was established in 1988 the quality is spectacular as well. With clarity and to reward and encourage journalists and other humor, Ian Stewart explains everything from num- communicators who, on a sustained basis, bring ber theory to fractals, from Euclidean geometry to accurate mathematical information to nonmathe- fluid dynamics, from game theory to foundations. matical audiences. Any person is eligible as long He conveys both the beauty and the utility of math- as that person’s work communicates primarily ematics in a way seldom achieved by a single au- with nonmathematical audiences. The lifetime thor, and he does so with charm and eloquence. award recognizes a significant contribution or ac- cumulated contributions to public understanding Biographical Sketch of mathematics. Ian Stewart was born in 1945, did his undergrad- At the Joint Mathematics Meetings in San An- uate degree at Cambridge, and his Ph.D. at Warwick. tonio in January 1999, the 1999 JPBM Communi- He is now a professor at Warwick University and cations Award was presented to IAN STEWART. Below director of the Mathematics Awareness Centre at is the award citation, a biographical sketch, and Warwick. He has held visiting positions in Ger- Stewart’s response upon receiving the award. This many, New Zealand, Connecticut, and Texas. He has is followed by information about a JPBM Special published over 120 papers. His present field is Communications Award presented to JOHN LYNCH the effects of symmetry on nonlinear dynamics, and SIMON SINGH. -
Cryptography: Decoding Student Learning
ABSTRACT PATTERSON, BLAIN ANTHONY. Cryptography: Decoding Student Learning. (Under the direction of Karen Keene.) Cryptography is a content field of mathematics and computer science, developed to keep information safe both when being sent between parties and stored. In addition to this, cryptography can also be used as a powerful teaching tool, as it puts mathematics in a dramatic and realistic setting. It also allows for a natural way to introduce topics such as modular arithmetic, matrix operations, and elementary group theory. This thesis reports the results of an analysis of students' thinking and understanding of cryptog- raphy using both the SOLO taxonomy and open coding as they participated in task based interviews. Students interviewed were assessed on how they made connections to various areas of mathematics through solving cryptography problems. Analyzing these interviews showed that students have a strong foundation in number theoretic concepts such as divisibility and modular arithmetic. Also, students were able to use probabil- ity intuitively to make sense of and solve problems. Finally, participants' SOLO levels ranged from Uni-structural to Extended Abstract, with Multi-Structural level being the most common (three participants). This gives evidence to suggest that students should be given the opportunity to make mathematical connections early and often in their academic careers. Results indicate that although cryptography should not be a required course by mathematics majors, concepts from this field could be introduced -
Key Agreement from Weak Bit Agreement
Key Agreement from Weak Bit Agreement Thomas Holenstein Department of Computer Science Swiss Federal Institute of Technology (ETH) Zurich, Switzerland [email protected] ABSTRACT In cryptography, much study has been devoted to find re- Assume that Alice and Bob, given an authentic channel, lations between different such assumptions and primitives. For example, Impagliazzo and Luby show in [9] that imple- have a protocol where they end up with a bit SA and SB , respectively, such that with probability 1+ε these bits are mentations of essentially all non-trivial cryptographic tasks 2 imply the existence of one-way functions. On the other equal. Further assume that conditioned on the event SA = hand, many important primitives can be realized if one-way SB no polynomial time bounded algorithm can predict the δ functions exist. Examples include pseudorandom generators bit better than with probability 1 − 2 . Is it possible to obtain key agreement from such a primitive? We show that [7], pseudorandom functions [5], and pseudorandom permu- 1−ε tations [12]. for constant δ and ε the answer is yes if and only if δ > 1+ε , both for uniform and non-uniform adversaries. For key agreement no such reduction to one-way functions The main computational technique used in this paper is a is known. In fact, in [10] it is shown that such a reduction strengthening of Impagliazzo’s hard-core lemma to the uni- must be inherently non-relativizing, and thus it seems very form case and to a set size parameter which is tight (i.e., hard to find such a construction. -
Polish Mathematicians Finding Patterns in Enigma Messages
Fall 2006 Chris Christensen MAT/CSC 483 Machine Ciphers Polyalphabetic ciphers are good ways to destroy the usefulness of frequency analysis. Implementation can be a problem, however. The key to a polyalphabetic cipher specifies the order of the ciphers that will be used during encryption. Ideally there would be as many ciphers as there are letters in the plaintext message and the ordering of the ciphers would be random – an one-time pad. More commonly, some rotation among a small number of ciphers is prescribed. But, rotating among a small number of ciphers leads to a period, which a cryptanalyst can exploit. Rotating among a “large” number of ciphers might work, but that is hard to do by hand – there is a high probability of encryption errors. Maybe, a machine. During World War II, all the Allied and Axis countries used machine ciphers. The United States had SIGABA, Britain had TypeX, Japan had “Purple,” and Germany (and Italy) had Enigma. SIGABA http://en.wikipedia.org/wiki/SIGABA 1 A TypeX machine at Bletchley Park. 2 From the 1920s until the 1970s, cryptology was dominated by machine ciphers. What the machine ciphers typically did was provide a mechanical way to rotate among a large number of ciphers. The rotation was not random, but the large number of ciphers that were available could prevent depth from occurring within messages and (if the machines were used properly) among messages. We will examine Enigma, which was broken by Polish mathematicians in the 1930s and by the British during World War II. The Japanese Purple machine, which was used to transmit diplomatic messages, was broken by William Friedman’s cryptanalysts. -
Block Ciphers
BLOCK CIPHERS MTH 440 Block ciphers • Plaintext is divided into blocks of a given length and turned into output ciphertext blocks of the same length • Suppose you had a block cipher, E(x,k) where the input plaintext blocks,x, were of size 5-bits and a 4-bit key, k. • PT = 10100010101100101 (17 bits), “Pad” the PT so that its length is a multiple of 5 (we will just pad with 0’s – it doesn’t really matter) • PT = 10100010101100101000 • Break the PT into blocks of 5-bits each (x=x1x2x3x4) where each xi is 5 bits) • x1=10100, x2= 01010, x3=11001, x4=01000 • Ciphertext: c1c2c3c4 where • c1=E(x1,k1), c2=E(x2,k2), c3=E(x3,k3), c4=E(x4,k4) • (when I write the blocks next to each other I just mean concatentate them (not multiply) – we’ll do this instead of using the || notation when it is not confusing) • Note the keys might all be the same or all different What do the E’s look like? • If y = E(x,k) then we’ll assume that we can decipher to a unique output so there is some function, we’ll call it D, so that x = D(y,k) • We might define our cipher to be repeated applications of some function E either with the same or different keys, we call each of these applications “round” • For example we might have a “3 round” cipher: y Fk x E((() E E x, k1 , k 2)), k 3 • We would then decipher via 1 x Fk (,, y) D((() D D y, k3 k 2) k 1) S-boxes (Substitution boxes) • Sometimes the “functions” used in the ciphers are just defined by a look up table that are often referred to “S- boxes” •x1 x 2 x 3 S(x 1 x 2 x 3 ) Define a 4-bit function with a 3-bit key 000 -
0137135599 Sample.Pdf
Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and the publisher was aware of a trademark claim, the designations have been printed with initial capital letters or in all capitals. The authors and publisher have taken care in the preparation of this book, but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of the use of the information or programs contained herein. The publisher offers excellent discounts on this book when ordered in quantity for bulk purchases or special sales, which may include electronic versions and/or custom covers and content particular to your business, training goals, marketing focus, and branding interests. For more information, please contact: U.S. Corporate and Government Sales (800) 382-3419 [email protected] For sales outside the United States, please contact: International Sales [email protected] Visit us on the Web: www.informit.com/aw Library of Congress Cataloging-in-Publication Data: Abelson, Harold. Blown to bits : your life, liberty, and happiness after the digital explosion / Hal Abelson, Ken Ledeen, Harry Lewis. p. cm. ISBN 0-13-713559-9 (hardback : alk. paper) 1. Computers and civilization. 2. Information technology—Technological innovations. 3. Digital media. I. Ledeen, Ken, 1946- II. Lewis, Harry R. III. Title. QA76.9.C66A245 2008 303.48’33—dc22 2008005910 Copyright © 2008 Hal Abelson, Ken Ledeen, and Harry Lewis All rights reserved. -
Identifying Open Research Problems in Cryptography by Surveying Cryptographic Functions and Operations 1
International Journal of Grid and Distributed Computing Vol. 10, No. 11 (2017), pp.79-98 http://dx.doi.org/10.14257/ijgdc.2017.10.11.08 Identifying Open Research Problems in Cryptography by Surveying Cryptographic Functions and Operations 1 Rahul Saha1, G. Geetha2, Gulshan Kumar3 and Hye-Jim Kim4 1,3School of Computer Science and Engineering, Lovely Professional University, Punjab, India 2Division of Research and Development, Lovely Professional University, Punjab, India 4Business Administration Research Institute, Sungshin W. University, 2 Bomun-ro 34da gil, Seongbuk-gu, Seoul, Republic of Korea Abstract Cryptography has always been a core component of security domain. Different security services such as confidentiality, integrity, availability, authentication, non-repudiation and access control, are provided by a number of cryptographic algorithms including block ciphers, stream ciphers and hash functions. Though the algorithms are public and cryptographic strength depends on the usage of the keys, the ciphertext analysis using different functions and operations used in the algorithms can lead to the path of revealing a key completely or partially. It is hard to find any survey till date which identifies different operations and functions used in cryptography. In this paper, we have categorized our survey of cryptographic functions and operations in the algorithms in three categories: block ciphers, stream ciphers and cryptanalysis attacks which are executable in different parts of the algorithms. This survey will help the budding researchers in the society of crypto for identifying different operations and functions in cryptographic algorithms. Keywords: cryptography; block; stream; cipher; plaintext; ciphertext; functions; research problems 1. Introduction Cryptography [1] in the previous time was analogous to encryption where the main task was to convert the readable message to an unreadable format.