CRYPTOGRAPHY You May Know What This Means
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Introduction to Cryptography Teachers' Reference
Introduction to Cryptography Teachers’ Reference Dear Teachers! Here I have mentioned some guidelines for your good self so that your students can benefit form these modules. I am very hopeful that you will enjoy conducting the session. After Module-1 1. Scytale Decryption In your class ask your students to devise a method to decrypt the message just been encrypted using Scytale. Encourage them to look around to find a decryption tool. Ask your students to cut a strip of paper some 4mm wide, 32cm long and light pencil lines drawn on it at 4mm distance. To give it the following shape. Now write cipher text on the paper strip in the following way. t i t i r s a e e e e e b h y w i t i l r f d n m g o e e o h v n t t r a a e c a g o o w d m h Encourage them once again to find a tool around them to decrypt it. Ask them to look for a very familiar thing they must have been using right from their early school days to do their work. Now many of them must have figured out that you are asking for a pencil. Now ask them to use the pencil to decrypt the cipher text by using pencil and the only reasonable way would be to wrap the paper strip around the strip. The plain text will be visible along the six side faces of the pencil. Encourage them to reason that how did it work? There is a connection between six rows of the table in which the plain text was filled and the six faces of the pencil. -
Enhancing the Security of Caesar Cipher Substitution Method Using a Randomized Approach for More Secure Communication
International Journal of Computer Applications (0975 – 8887) Volume 129 – No.13, November2015 Enhancing the Security of Caesar Cipher Substitution Method using a Randomized Approach for more Secure Communication Atish Jain Ronak Dedhia Abhijit Patil Dept. of Computer Engineering Dept. of Computer Engineering Dept. of Computer Engineering D.J. Sanghvi College of D.J. Sanghvi College of D.J. Sanghvi College of Engineering Engineering Engineering Mumbai University, Mumbai, Mumbai University, Mumbai, Mumbai University, Mumbai, India India India ABSTRACT communication can be encoded to prevent their contents from Caesar cipher is an ancient, elementary method of encrypting being disclosed through various techniques like interception plain text message into cipher text protecting it from of message or eavesdropping. Different ways include using adversaries. However, with the advent of powerful computers, ciphers, codes, substitution, etc. so that only the authorized there is a need for increasing the complexity of such people can view and interpret the real message correctly. techniques. This paper contributes in the area of classical Cryptography concerns itself with four main objectives, cryptography by providing a modified and expanded version namely, 1) Confidentiality, 2) Integrity, 3) Non-repudiation for Caesar cipher using knowledge of mathematics and and 4) Authentication. [1] computer science. To increase the strength of this classical Cryptography is divided into two types, Symmetric key and encryption technique, the proposed modified algorithm uses Asymmetric key cryptography. In Symmetric key the concepts of affine ciphers, transposition ciphers and cryptography a single key is shared between sender and randomized substitution techniques to create a cipher text receiver. The sender uses the shared key and encryption which is nearly impossible to decode. -
Quantum Cryptography Without Basis Switching 2004
Quantum Cryptography Without Basis Switching Christian Weedbrook B.Sc., University of Queensland, 2003. A thesis submitted for the degree of Bachelor of Science Honours in Physics The Australian National University October 2004 ii iii Listen, do you want to know a secret? Do you promise not to tell? - John Lennon and Paul McCartney iv Declaration This thesis is an account of research undertaken with the supervision of Dr Ping Koy Lam, Dr Tim Ralph and Dr Warwick Bowen between February 2004 and October 2004. It is a partial fulfilment of the requirements for the degree of a Bachelor of Science with Honours in theoretical physics at the Australian National University, Canberra, Australia. Except where acknowledged in the customary manner, the material presented in this thesis is, to the best of my knowledge, original and has not been submitted in whole or part for a degree in any university. Christian Weedbrook 29th October 2004 v vi Acknowledgements During the three years of residency, it was the relationships that got you through. - J.D., Scrubs I have met a lot of people during my Honours year, and a lot of people to thank and be thankful for. First I would like to thank my supervisors Ping Koy Lam, Tim Ralph, Warwick Bowen and my “unofficial” supervisor Andrew Lance. Ping Koy, thank you for your positive approach and enthusiasm. It was excellent having you as my supervisor, as you have many ideas and the ability to know the best way to proceed. I would like to thank you for my scholarship and also for organizing that I could do my Honours at ANU, and to spend some time up at UQ. -
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. -
Simple Substitution and Caesar Ciphers
Spring 2015 Chris Christensen MAT/CSC 483 Simple Substitution Ciphers The art of writing secret messages – intelligible to those who are in possession of the key and unintelligible to all others – has been studied for centuries. The usefulness of such messages, especially in time of war, is obvious; on the other hand, their solution may be a matter of great importance to those from whom the key is concealed. But the romance connected with the subject, the not uncommon desire to discover a secret, and the implied challenge to the ingenuity of all from who it is hidden have attracted to the subject the attention of many to whom its utility is a matter of indifference. Abraham Sinkov In Mathematical Recreations & Essays By W.W. Rouse Ball and H.S.M. Coxeter, c. 1938 We begin our study of cryptology from the romantic point of view – the point of view of someone who has the “not uncommon desire to discover a secret” and someone who takes up the “implied challenged to the ingenuity” that is tossed down by secret writing. We begin with one of the most common classical ciphers: simple substitution. A simple substitution cipher is a method of concealment that replaces each letter of a plaintext message with another letter. Here is the key to a simple substitution cipher: Plaintext letters: abcdefghijklmnopqrstuvwxyz Ciphertext letters: EKMFLGDQVZNTOWYHXUSPAIBRCJ The key gives the correspondence between a plaintext letter and its replacement ciphertext letter. (It is traditional to use small letters for plaintext and capital letters, or small capital letters, for ciphertext. We will not use small capital letters for ciphertext so that plaintext and ciphertext letters will line up vertically.) Using this key, every plaintext letter a would be replaced by ciphertext E, every plaintext letter e by L, etc. -
Cryptography in Modern World
Cryptography in Modern World Julius O. Olwenyi, Aby Tino Thomas, Ayad Barsoum* St. Mary’s University, San Antonio, TX (USA) Emails: [email protected], [email protected], [email protected] Abstract — Cryptography and Encryption have been where a letter in plaintext is simply shifted 3 places down used for secure communication. In the modern world, the alphabet [4,5]. cryptography is a very important tool for protecting information in computer systems. With the invention ABCDEFGHIJKLMNOPQRSTUVWXYZ of the World Wide Web or Internet, computer systems are highly interconnected and accessible from DEFGHIJKLMNOPQRSTUVWXYZABC any part of the world. As more systems get interconnected, more threat actors try to gain access The ciphertext of the plaintext “CRYPTOGRAPHY” will to critical information stored on the network. It is the be “FUBSWRJUASLB” in a Caesar cipher. responsibility of data owners or organizations to keep More recent derivative of Caesar cipher is Rot13 this data securely and encryption is the main tool used which shifts 13 places down the alphabet instead of 3. to secure information. In this paper, we will focus on Rot13 was not all about data protection but it was used on different techniques and its modern application of online forums where members could share inappropriate cryptography. language or nasty jokes without necessarily being Keywords: Cryptography, Encryption, Decryption, Data offensive as it will take those interested in those “jokes’ security, Hybrid Encryption to shift characters 13 spaces to read the message and if not interested you do not need to go through the hassle of converting the cipher. I. INTRODUCTION In the 16th century, the French cryptographer Back in the days, cryptography was not all about Blaise de Vigenere [4,5], developed the first hiding messages or secret communication, but in ancient polyalphabetic substitution basically based on Caesar Egypt, where it began; it was carved into the walls of cipher, but more difficult to crack the cipher text. -
IMPLEMENTASI ALGORITMA CAESAR, CIPHER DISK, DAN SCYTALE PADA APLIKASI ENKRIPSI DAN DEKRIPSI PESAN SINGKAT, Lumasms
Prosiding Seminar Ilmiah Nasional Komputer dan Sistem Intelijen (KOMMIT 2014) Vol. 8 Oktober 2014 Universitas Gunadarma – Depok – 14 – 15 Oktober 2014 ISSN : 2302-3740 IMPLEMENTASI ALGORITMA CAESAR, CIPHER DISK, DAN SCYTALE PADA APLIKASI ENKRIPSI DAN DEKRIPSI PESAN SINGKAT, LumaSMS Yusuf Triyuswoyo ST. 1 Ferina Ferdianti ST. 2 Donny Ajie Baskoro ST. 3 Lia Ambarwati ST. 4 Septiawan ST. 5 1,2,3,4,5Jurusan Manajemen Sistem Informasi, Universitas Gunadarma [email protected] Abstrak Short Message Service (SMS) merupakan salah satu cara berkomunikasi yang banyak digunakan oleh pengguna telepon seluler. Namun banyaknya pengguna telepon seluler yang menggunakan layanan SMS, tidak diimbangi dengan faktor keamanan yang ada pada layanan tersebut. Banyak pengguna telepon seluler yang belum menyadari bahwa SMS tidak menjamin integritas dan keamanan pesan yang disampaikan. Ada beberapa risiko yang dapat mengancam keamanan pesan pada layanan SMS, diantaranya: SMS spoofing, SMS snooping, dan SMS interception. Untuk mengurangi risiko tersebut, maka dibutuhkan sebuah sistem keamanan pada layanan SMS yang mampu menjaga integritas dan keamanan isi pesan. Dimana tujuannya ialah untuk menutupi celah pada tingkat keamanan SMS. Salah satu penanggulangannya ialah dengan menerapkan algoritma kriptografi, yaitu kombinasi atas algoritma Cipher Disk, Caesar, dan Scytale pada pesan yang akan dikirim. Tujuan dari penulisan ini adalah membangun aplikasi LumaSMS, dengan menggunakan kombinasi ketiga algoritma kriptografi tersebut. Dengan adanya aplikasi ini diharapkan mampu mengurangi masalah keamanan dan integritas SMS. Kata Kunci: caesar, cipher disk, kriptografi, scytale, SMS. PENDAHULUAN dibutuhkan dikarenakan SMS mudah digunakan dan biaya yang dikeluarkan Telepon seluler merupakan salah untuk mengirim SMS relatif murah. satu hasil dari perkembangan teknologi Namun banyaknya pengguna komunikasi. -
Cryptanalysis of Mono-Alphabetic Substitution Ciphers Using Genetic Algorithms and Simulated Annealing Shalini Jain Marathwada Institute of Technology, Dr
Vol. 08 No. 01 2018 p-ISSN 2202-2821 e-ISSN 1839-6518 (Australian ISSN Agency) 82800801201801 Cryptanalysis of Mono-Alphabetic Substitution Ciphers using Genetic Algorithms and Simulated Annealing Shalini Jain Marathwada Institute of Technology, Dr. Babasaheb Ambedkar Marathwada University, India Nalin Chhibber University of Waterloo, Ontario, Canada Sweta Kandi Marathwada Institute of Technology, Dr. Babasaheb Ambedkar Marathwada University, India ABSTRACT – In this paper, we intend to apply the principles of genetic algorithms along with simulated annealing to cryptanalyze a mono-alphabetic substitution cipher. The type of attack used for cryptanalysis is a ciphertext-only attack in which we don’t know any plaintext. In genetic algorithms and simulated annealing, for ciphertext-only attack, we need to have the solution space or any method to match the decrypted text to the language text. However, the challenge is to implement the project while maintaining computational efficiency and a high degree of security. We carry out three attacks, the first of which uses genetic algorithms alone, the second which uses simulated annealing alone and the third which uses a combination of genetic algorithms and simulated annealing. Key words: Cryptanalysis, mono-alphabetic substitution cipher, genetic algorithms, simulated annealing, fitness I. Introduction II. Mono-alphabetic substitution cipher Cryptanalysis involves the dissection of computer systems by A mono-alphabetic substitution cipher is a class of substitution unauthorized persons in order to gain knowledge about the ciphers in which the same letters of the plaintext are replaced unknown aspects of the system. It can be used to gain control by the same letters of the ciphertext. -
I – Basic Notions
Provable Security in the Computational Model I – Basic Notions David Pointcheval MPRI – Paris Ecole normale superieure,´ CNRS & INRIA ENS/CNRS/INRIA Cascade David Pointcheval 1/71 Outline Cryptography Provable Security Basic Security Notions Conclusion ENS/CNRS/INRIA Cascade David Pointcheval 2/71 Cryptography Outline Cryptography Introduction Kerckhoffs’ Principles Formal Notations Provable Security Basic Security Notions Conclusion ENS/CNRS/INRIA Cascade David Pointcheval 3/71 Secrecy of Communications One ever wanted to communicate secretly The treasure Bob is under Alice …/... ENS/CNRS/INRIA Cascade David Pointcheval 4/71 Secrecy of Communications One ever wanted to communicate secretly The treasure Bob is under Alice …/... ENS/CNRS/INRIA Cascade David Pointcheval 4/71 Secrecy of Communications One ever wanted to communicate secretly The treasure Bob is under Alice …/... ENS/CNRS/INRIA Cascade David Pointcheval 4/71 Secrecy of Communications One ever wanted to communicate secretly The treasure Bob is under Alice …/... ENS/CNRS/INRIA Cascade David Pointcheval 4/71 Secrecy of Communications One ever wanted to communicate secretly The treasure Bob is under Alice …/... With the all-digital world, security needs are even stronger ENS/CNRS/INRIA Cascade David Pointcheval 4/71 Old Methods Substitutions and permutations Security relies on the secrecy of the mechanism ENS/CNRS/INRIA Cascade David Pointcheval 5/71 Old Methods Substitutions and permutations Security relies on the secrecy of the mechanism Scytale - Permutation ENS/CNRS/INRIA -
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 -
CS 241 Data Organization Ciphers
CS 241 Data Organization Ciphers March 22, 2018 Cipher • In cryptography, a cipher (or cypher) is an algorithm for performing encryption or decryption. • When using a cipher, the original information is known as plaintext, and the encrypted form as ciphertext. • The encrypting procedure of the cipher usually depends on a piece of auxiliary information, called a key. • A key must be selected before using a cipher to encrypt a message. • Without knowledge of the key, it should be difficult, if not nearly impossible, to decrypt the resulting ciphertext into readable plaintext. Substitution Cipher • In cryptography, a substitution cipher is a method of encryption by which units of plaintext are replaced with ciphertext according to a regular system. • Example: case insensitive substitution cipher using a shifted alphabet with keyword "zebras": • Plaintext alphabet: ABCDEFGHIJKLMNOPQRSTUVWXYZ • Ciphertext alphabet: ZEBRASCDFGHIJKLMNOPQTUVWXY flee at once. we are discovered! Enciphers to SIAA ZQ LKBA. VA ZOA RFPBLUAOAR! Other substitution ciphers Caesar cipher Shift alphabet by fixed amount. (Caesar apparently used 3.) ROT13 Replace letters with those 13 away. Used to hide spoilers on newsgroups. pigpen cipher Replace letters with symbols. Substitution Cipher: Encipher Example OENp(ENTE#X@EN#zNp(ENCL]pEnN7p-pE;8N]LN} dnEdNp#Nz#duN-Nu#dENXEdzE9pNCL]#L8NE;p-b @];(N0G;p]9E8N]L;GdENn#uE;p]9Nld-L/G]@]p _8NXd#|]nENz#dNp(EN9#uu#LNnEzEL;E8NXd#u# pENp(ENQELEd-@NOE@z-dE8N-LnN;E9GdENp(EN^ @E;;]LQ;N#zN<]bEdp_Np#N#Gd;E@|E;N-LnN#Gd NT#;pEd]p_8Nn#N#dn-]LN-LnNE;p-b@];(Np(]; N5#L;p]pGp]#LNz#dNp(ENCL]pEnN7p-pE;N#zN) uEd]9-D Breaking a Substitution Cipher In English, • The most common character is the space: \ ". -
Recommendation for Block Cipher Modes of Operation Methods
NIST Special Publication 800-38A Recommendation for Block 2001 Edition Cipher Modes of Operation Methods and Techniques Morris Dworkin C O M P U T E R S E C U R I T Y ii C O M P U T E R S E C U R I T Y Computer Security Division Information Technology Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899-8930 December 2001 U.S. Department of Commerce Donald L. Evans, Secretary Technology Administration Phillip J. Bond, Under Secretary of Commerce for Technology National Institute of Standards and Technology Arden L. Bement, Jr., Director iii Reports on Information Security Technology The Information Technology Laboratory (ITL) at the National Institute of Standards and Technology (NIST) promotes the U.S. economy and public welfare by providing technical leadership for the Nation’s measurement and standards infrastructure. ITL develops tests, test methods, reference data, proof of concept implementations, and technical analyses to advance the development and productive use of information technology. ITL’s responsibilities include the development of technical, physical, administrative, and management standards and guidelines for the cost-effective security and privacy of sensitive unclassified information in Federal computer systems. This Special Publication 800-series reports on ITL’s research, guidance, and outreach efforts in computer security, and its collaborative activities with industry, government, and academic organizations. Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the entities, materials, or equipment are necessarily the best available for the purpose.