George Lasry: Modern Cryptanalysis of Historical Ciphers
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International Journal for Scientific Research & Development
IJSRD - International Journal for Scientific Research & Development| Vol. 6, Issue 03, 2018 | ISSN (online): 2321-0613 Designing of Decryption Tool Shashank Singh1 Vineet Shrivastava2 Shiva Agrawal3 Shakti Singh Rawat4 1,3,4Student 2Assistant Professor 1,2,3,4Department of Information Technology 1,2,3,4SRM Institute of Science & Technology, India Abstract— In the modern world secure transmission of the r = gk mod p data is very important. Many modern day cryptographic methods can be used to encrypt the message before C. Decryption of the Cipher-text transmitting in the secured medium. In certain situations like The receiver with his private key calculates when there is matter of national security the information t. r−x encrypted has to be decrypted, it is where the cryptanalysis which gives the plaintext. comes into play. Cryptanalysis is the field of Cryptography in But in this algorithm, as there is just one private key, it can which various types of Cryptographic techniques are be guessed by any intruder and is thus not reliable. carefully studied in order to reverse engineer the encrypted information in order to retrieve the sensible information. The III. PROBLEM SOLUTION main aim and function of the Decryption tool is to take the In this project we are modifying the existing conventional input as the encrypted text given from the user and encryption algorithm by dividing the private key and cryptanalyze it and give the output as the decrypted text in assigning them to 2n+1 authorized receivers individually. case more than one sensible decrypted text found it will The persons will be able to decrypt the message received output all the possible decrypted texts. -
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International Journal of Integrated Engineering: Special Issue 2018: Data Information Engineering, Vol. 10 No. 6 (2018) p. 183-192. © Penerbit UTHM DOI: https://doi.org/10.30880/ijie.2018.10.06.026 Analysis of Four Historical Ciphers Against Known Plaintext Frequency Statistical Attack Chuah Chai Wen1*, Vivegan A/L Samylingam2, Irfan Darmawan3, P.Siva Shamala A/P Palaniappan4, Cik Feresa Mohd. Foozy5, Sofia Najwa Ramli6, Janaka Alawatugoda7 1,2,4,5,6Information Security Interest Group (ISIG), Faculty Computer Science and Information Technology University Tun Hussein Onn Malaysia, Batu Pahat, Johor, Malaysia E-mail: [email protected], [email protected], {shamala, feresa, sofianajwa}@uthm.edu.my 3School of Industrial Engineering, Telkom University, 40257 Bandung, West Java, Indonesia 7Department of Computer Engineering, University of Peradeniya, Sri Lanka E-mail: [email protected] Received 28 June 2018; accepted 5August 2018, available online 24 August 2018 Abstract: The need of keeping information securely began thousands of years. The practice to keep the information securely is by scrambling the message into unreadable form namely ciphertext. This process is called encryption. Decryption is the reverse process of encryption. For the past, historical ciphers are used to perform encryption and decryption process. For example, the common historical ciphers are Hill cipher, Playfair cipher, Random Substitution cipher and Vigenère cipher. This research is carried out to examine and to analyse the security level of these four historical ciphers by using known plaintext frequency statistical attack. The result had shown that Playfair cipher and Hill cipher have better security compare with Vigenère cipher and Random Substitution cipher. -
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. -
An Extension to Traditional Playfair Cryptographic Method
International Journal of Computer Applications (0975 – 8887) Volume 17– No.5, March 2011 An Extension to Traditional Playfair Cryptographic Method Ravindra Babu K¹, S. Uday Kumar ², A. Vinay Babu ³, I.V.N.S Aditya4 , P. Komuraiah5 ¹Research Scholar (JTNUH) & Professor in CSE, VITS SET, Kareemnagar, AP, India. ²Deputy Director, Professor in CSE. SNIST, JNTUH. Hyderabad, Andhra Pradesh, India. ³Director, Admissions, Jawaharlal Nehru Technological University, Hyderabad, Andhra Pradesh, India. 4Computer Science & Engineering, AZCET, Mancherial. 5HOD IT, VITS SET, Kareemnagar, AP, India. ABSTRACT Fig 1: General cryptographic system. The theme of our research is to provide security for the data that contains alphanumeric values during its transmission. The best known multiple letter encryption cipher is the play fair, which treats the plain text as single units and translates these units into cipher text. It is highly difficult to the intruder to understand or to decrypt the cipher text. In this we discussed about the existing play fair algorithm, its merits and demerits. The existing play fair algorithm is based on the use of a 5 X 5 matrix of letters constructed using a keyword. This algorithm can only allow the text that contains alphabets only. For this we have proposed an enhancement to the existing algorithm, that a 6 X 6 matrix can be constructed. General Terms Encryption, Decryption, Plaintext, Cipher text. 2. EXISTING TECHNIQUES All cryptographic algorithms are based on two general Keywords principals: substitution, in which each element in the plaintext Substitution, Transposition. (bit, letter and group of bits or letters) is mapped into another element and in transposition, the elements of the plaintext have 1. -
Classifying Classic Ciphers Using Machine Learning
San Jose State University SJSU ScholarWorks Master's Projects Master's Theses and Graduate Research Spring 5-20-2019 Classifying Classic Ciphers using Machine Learning Nivedhitha Ramarathnam Krishna San Jose State University Follow this and additional works at: https://scholarworks.sjsu.edu/etd_projects Part of the Artificial Intelligence and Robotics Commons, and the Information Security Commons Recommended Citation Krishna, Nivedhitha Ramarathnam, "Classifying Classic Ciphers using Machine Learning" (2019). Master's Projects. 699. DOI: https://doi.org/10.31979/etd.xkgs-5gy6 https://scholarworks.sjsu.edu/etd_projects/699 This Master's Project is brought to you for free and open access by the Master's Theses and Graduate Research at SJSU ScholarWorks. It has been accepted for inclusion in Master's Projects by an authorized administrator of SJSU ScholarWorks. For more information, please contact [email protected]. Classifying Classic Ciphers using Machine Learning A Project Presented to The Faculty of the Department of Computer Science San José State University In Partial Fulfillment of the Requirements for the Degree Master of Science by Nivedhitha Ramarathnam Krishna May 2019 © 2019 Nivedhitha Ramarathnam Krishna ALL RIGHTS RESERVED The Designated Project Committee Approves the Project Titled Classifying Classic Ciphers using Machine Learning by Nivedhitha Ramarathnam Krishna APPROVED FOR THE DEPARTMENT OF COMPUTER SCIENCE SAN JOSÉ STATE UNIVERSITY May 2019 Dr. Mark Stamp Department of Computer Science Dr. Thomas Austin Department of Computer Science Professor Fabio Di Troia Department of Computer Science ABSTRACT Classifying Classic Ciphers using Machine Learning by Nivedhitha Ramarathnam Krishna We consider the problem of identifying the classic cipher that was used to generate a given ciphertext message. -
The Enigma Encryption Machine and Its Electronic Variant
The Enigma Encryption Machine and its Electronic Variant Michel Barbeau, VE3EMB What is the Enigma? possible initial settings, making the total number of initial settings in the order of 10 power 16. The The Enigma is a machine devised for encrypting initial setting, taken from a code book, indicates plain text into cipher text. The machine was which pairs of letters (if any) are switched with each invented in 1918 by the German engineer Arthur other. The initial setting is called the secret key. Scherbius who lived from 1878 to 1929. The German Navy adopted the Enigma in 1925 to secure World War II was fought from 1939 to 1945 their communications. The machine was also used between the Allies (Great Britain, Russia, the by the Nazi Germany during World War II to cipher United States, France, Poland, Canada and others) radio messages. The cipher text was transmitted in and the Germans (with the Axis). To minimize the Morse code by wireless telegraph to the destination chance of the Allies cracking their code, the where a second Enigma machine was used to Germans changed the secret key each day. decrypt the cipher text back into the original plain text. Both the encrypting and decrypting Enigma The codes used for the naval Enigmas, had machines had identical settings in order for the evocative names given by the germans. Dolphin decryption to succeed. was the main naval cipher. Oyster was the officer’s variant of Dolphin. Porpoise was used for The Enigma consists of a keyboard, a scrambling Mediterranean surface vessels and shipping in the unit, a lamp board and a plug board. -
The Mathemathics of Secrets.Pdf
THE MATHEMATICS OF SECRETS THE MATHEMATICS OF SECRETS CRYPTOGRAPHY FROM CAESAR CIPHERS TO DIGITAL ENCRYPTION JOSHUA HOLDEN PRINCETON UNIVERSITY PRESS PRINCETON AND OXFORD Copyright c 2017 by Princeton University Press Published by Princeton University Press, 41 William Street, Princeton, New Jersey 08540 In the United Kingdom: Princeton University Press, 6 Oxford Street, Woodstock, Oxfordshire OX20 1TR press.princeton.edu Jacket image courtesy of Shutterstock; design by Lorraine Betz Doneker All Rights Reserved Library of Congress Cataloging-in-Publication Data Names: Holden, Joshua, 1970– author. Title: The mathematics of secrets : cryptography from Caesar ciphers to digital encryption / Joshua Holden. Description: Princeton : Princeton University Press, [2017] | Includes bibliographical references and index. Identifiers: LCCN 2016014840 | ISBN 9780691141756 (hardcover : alk. paper) Subjects: LCSH: Cryptography—Mathematics. | Ciphers. | Computer security. Classification: LCC Z103 .H664 2017 | DDC 005.8/2—dc23 LC record available at https://lccn.loc.gov/2016014840 British Library Cataloging-in-Publication Data is available This book has been composed in Linux Libertine Printed on acid-free paper. ∞ Printed in the United States of America 13579108642 To Lana and Richard for their love and support CONTENTS Preface xi Acknowledgments xiii Introduction to Ciphers and Substitution 1 1.1 Alice and Bob and Carl and Julius: Terminology and Caesar Cipher 1 1.2 The Key to the Matter: Generalizing the Caesar Cipher 4 1.3 Multiplicative Ciphers 6 -
Historical Ciphers Systems Top 10 Open Problems May 5, 2016 George Lasry [email protected] Open Problems - Criteria
Historical Ciphers Systems Top 10 Open Problems May 5, 2016 George Lasry [email protected] Open Problems - Criteria • Generic method vs. deciphering a document • System details are known – For many there are simulators • Published methods vs. classified • General vs. special case solutions – Ciphertext only vs. known plaintext – Single message vs. in-depth messages – Short vs. long messages – Long vs. short keys • Brute force not feasible – But computer most likely required George Lasry May 2016 2 Top 10 Open Problems 1. SIGABA 2. KL-7 3. Siemens T52D “Sturgeon” 4. Hagelin CX-52 5. Fialka 6. Lorenz SZ42 “Tunny” – Ψ1 limitation 7. Hagelin M-209 – short messages 8. Double Transposition – long random keys 9. Enigma – short message 10. Chaocipher – single message George Lasry May 2016 3 Problem 1: SIGABA (US) • Possible keys (WWII): 2 96 = 10 29 • Best published: known-plaintext 2 60 = 10 18 steps George Lasry May 2016 4 Problem 2: KL-7 (US) • Details of the machine known (+ simulator) • Best published cryptanalytic method: None! George Lasry May 2016 5 Problem 3: Siemens & Halske T52D • Successor of T52a/b/c: Irregular wheel stepping • Possible key settings: 2 73 = 10 24 • Best published method: > 5 messages in depth George Lasry May 2016 6 Problem 4: Hagelin CX-52 • Successor of C38/M209: Irregular wheel stepping • Possible key settings: 2 439 = 10 132 • Best published method: Known-plaintext George Lasry May 2016 7 Problem 5: Fialka M-125 (Russia) • Possible key settings: 2 250 = 10 75 • Best published method: None! George -
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. -
Cryptography
Cryptography A Brief History and Introduction MATH/COSC 314 Based on slides by Anne Ho Carolina Coastal University What is cryptography? κρυπτός γράφω “hidden, secret” “writing” ● Cryptology Study of communication securely over insecure channels ● Cryptography Writing (or designing systems to write) messages securely ● Cryptanalysis Study of methods to analyze and break hidden messages Secure Communications ● Alice wants to send Bob a secure message. ● Examples: ○ Snapchat snap ○ Bank account information ○ Medical information ○ Password ○ Dossier for a secret mission (because Bob is a field agent for an intelligence agency and Alice is his boss) Secure Communications Encryption Decryption Key Key Plaintext Ciphertext Plaintext Alice Encrypt Decrypt Bob Eve ● Symmetric Key: Alice and Bob use a (preshared) secret key. ● Public Key: Bob makes an encryption key public that Alice uses to encrypt a message. Only Bob has the decryption key. Possible Attacks Eve (the eavesdropper) is trying to: ● Read Alice’s message. ● Find Alice’s key to read all of Alice’s messages. ● Corrupt Alice’s message, so Bob receives an altered message. ● Pretend to be Alice and communicate with Bob. Why this matters ● Confidentiality Only Bob should be able to read Alice’s message. ● Data integrity Alice’s message shouldn’t be altered in any way. ● Authentication Bob wants to make sure Alice actually sent the message. ● Non-repudiation Alice cannot claim she didn’t send the message. Going back in time… 5th century BC King Xerxes I of Persia Definitely not historically accurate. Based on Frank Miller’s graphic novel, not history. 5th century BC Secret writing and steganography saved Greece from being completely conquered. -
Playfair Cipher and Shift Cipher Kriptografi – 3Rd Week
“ Add your company slogan ” Playfair Cipher and Shift Cipher Kriptografi – 3rd Week LOGO Aisyatul Karima, 2012 . Standar kompetensi . Pada akhir semester, mahasiswa menguasai pengetahuan, pengertian, & pemahaman tentang teknik-teknik kriptografi. Selain itu mahasiswa diharapkan mampu mengimplementasikan salah satu teknik kriptografi untuk mengamankan informasi yang akan dikirimkan melalui jaringan. Kompetensi dasar . Mahasiswa menguasai teknik playfair cipher . Mahasiswa menguasai teknik shift cipher Contents 1 Play fair Cipher Method 2 Shift Cipher Method Playfair Cipher Method . Playfair cipher or Playfair square is symetric encryption technique that member of digraph substitution technique. This technique encrypt digraph or pair of alphabet . Based on the reason, this technique hard to encode compare with the simple substitution technique. Playfair Cipher Method . This technique found by Charles Wheatstone on physics he is founder of wheatstone bridge on 1854. Charles Wheatstone . But, popularized by Lord Playfair. Lord Playfair Playfair Cipher Method . The process of playfair cipher : . The key composed by 25 letters that arranged in a square 5x5 by removing the letter J from alphabet. S T A N D E R C H B K F G I L M O P Q U V W X Y Z ????? . contoh kunci yang digunakan . Jumlah kemungkinan kunci dari sistem ini adalah : 25!=15.511.210.043.330.985.984.000.000 Playfair Cipher Method . The keys on square expanded by adding the 6th column and the 6th row. 6th column = 1st column S T A N D S E R C H B E K F G I L K M O P Q U M V W X Y Z V S T A N D 6th row = 1st row Playfair Cipher Method . -
Work Load of the Maintenance Branch
HEADQUARTERS ARMY SECURITY AGENCY WASHINGTON 25, D. C. WDGSS-85 15 May 1946 SUBJECT: Work Load of the Maintenance Branch TO: Chief, Security Division 1. The Repair Section of Maintenance Branch is .faced with an ex tremely heavy backlog of' work due to the large amounts of' cryptographic equipment returned from overseas for rehabilitation. Awaiting rehabili tation by the Repair Section is the followi~g list of equipment and the man hours estimated to complete the work required.: EQUIPMENT MAN HOURS REQUIRED TOTAL 1808 SIGABA 36 65,088 1182 SIGCUM 12 14,184 300 SIGNIN 4 1,200 2297 SIGIVI 4 9,188 533 SIGAMUG 4, 2,132 Total man hours 91,792 These figures represent the number of equipments on hand as of 1 May 1946 and will be continually increased by the arrival of additional equipment . from overseas. 2. It is considered probable that the SIGABA will be modified along the lines proposed by the Navy. It is proposed that all SIGABA 1s be modi fied at this Headquarters before shipment is made to the field, thus in creasing the work load as follows: EQUIPMENT MAN HOURS REQUIRED 3241 SIGABA 12 The above figure of' twelve hours per machine is an estimate based on preliminary studies of' the proposed change. It may be possible to greatly reduce this total af'ter the changes have been f inaJ.ly agreed on by the .Army and the Navy, and time studies can be made under actual conditions. ,3. In order to properly preserve these equipments while in extended storage, it is recommended that the proposals set .forth in a memorandum to the Chief, Security Division, 4 December 1945, subject "Preparation of Declassified and approved for release by NSA on 01-16-2014 pursuantto E .0.