Computer and Data Security Class 4 ﺳﻜﻴﻨﺔ ﺣﺴﻦ هﺎﺷﻢ . د: أﺳﺘﺎذة اﻟﻤﺎدة
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
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. -
A Covert Encryption Method for Applications in Electronic Data Interchange
Technological University Dublin ARROW@TU Dublin Articles School of Electrical and Electronic Engineering 2009-01-01 A Covert Encryption Method for Applications in Electronic Data Interchange Jonathan Blackledge Technological University Dublin, [email protected] Dmitry Dubovitskiy Oxford Recognition Limited, [email protected] Follow this and additional works at: https://arrow.tudublin.ie/engscheleart2 Part of the Digital Communications and Networking Commons, Numerical Analysis and Computation Commons, and the Software Engineering Commons Recommended Citation Blackledge, J., Dubovitskiy, D.: A Covert Encryption Method for Applications in Electronic Data Interchange. ISAST Journal on Electronics and Signal Processing, vol: 4, issue: 1, pages: 107 -128, 2009. doi:10.21427/D7RS67 This Article is brought to you for free and open access by the School of Electrical and Electronic Engineering at ARROW@TU Dublin. It has been accepted for inclusion in Articles by an authorized administrator of ARROW@TU Dublin. For more information, please contact [email protected], [email protected]. This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License A Covert Encryption Method for Applications in Electronic Data Interchange Jonathan M Blackledge, Fellow, IET, Fellow, BCS and Dmitry A Dubovitskiy, Member IET Abstract— A principal weakness of all encryption systems is to make sure that the ciphertext is relatively strong (but not that the output data can be ‘seen’ to be encrypted. In other too strong!) and that the information extracted is of good words, encrypted data provides a ‘flag’ on the potential value quality in terms of providing the attacker with ‘intelligence’ of the information that has been encrypted. -
Improved Cryptosystem Using SDES Algorithm with Substitution Ciphers G.Suman * , Ch
Volume 3, Issue 7, July 2013 ISSN: 2277 128X International Journal of Advanced Research in Computer Science and Software Engineering Research Paper Available online at: www.ijarcsse.com Improved Cryptosystem Using SDES Algorithm with Substitution Ciphers G.Suman * , Ch. Krishna M. Tech (SE) & SNIST. India Abstract— Security is playing a very important and crucial role in the field of network communication system and Internet. Simplified Data encryption standard (SDES) is a private key cryptography system that provides the security in communication system but now a days the advancement in the computational power the SDES seems to be weak against the brute force attacks. To improve the security of SDES algorithm the substitution techniques are added before the SDES algorithm to perform its process. By using an Improved Cryptosystem the security has been improved which is very crucial in the communication and field of Internet. If the substitution techniques are used before the original SDES algorithm then the intruder required first to break the original SDES algorithm and then substitution techniques. So the security is more as compared to a SDES algorithm. Keywords— Cipher text, Decryption, SDES, Encryption, Plain text, OPBFT,OPBTS ,Substitution. I. Introduction The process of encoding the plaintext into cipher text is called Encryption and the process of decoding ciphers text to plaintext is called Decryption. This can be done by two techniques symmetric-key cryptography and asymmetric key cryptography. Symmetric key cryptography involves the usage of the same key for encryption and decryption. But the Asymmetric key cryptography involves the usage of one key for encryption and another different key for decryption. -
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: \ ". -
Tap Code 1 2 3 4 5 1 a B C D E 2 F G H I J 3 L M N O P 4 Q R S T U 5
Solution to Kryptos 2: Challenge 1 The audio files indicate that the prisoners are communicating with each other by “tapping”. There are two distinct tapping sounds which indicate the two prisoners are exchanging some sort of information back and forth. Furthermore, unlike Morse Code, each audio file is made up of pairs of taps which leads one to believe that each pair of taps corresponds to a word or letter. The longest tapping sequence is five, so if one assumes that each tap-pair corresponds to a pair of integers between 1 and 5, then this code could encipher 25 items – most likely letters. At this point, one could try a frequency analysis to help identify which pairs of integers correspond to which letters. Alternatively, a little research might yield the “tap code” (see e.g. Wikipedia) which has been used by prisoners of war in various conflicts throughout history, most recently Vietnam. It is based on the Polybius square, some of which have slightly different arrangements of the 26 letters placed into 25 cells. Challenge 1 was based on the following key found on Wikipedia: Tap code 1 2 3 4 5 1 A B C D E 2 F G H I J 3 L M N O P 4 Q R S T U 5 V W X Y Z The tap code table This has all letters except “K”, so “C” is used instead. The letter “X” is used to separate sentences. The first audio file begins with the following tap-pairs: (2,4), (4,3), (1,3), (3,4), (5,1), (1,5), (4,2),… which yields the following plaintext: i, s, c, o, v, e, r, … By adding in the likely punctuation, the complete conversation can be decoded: PLAINTEXT Prisoner 1: Is cover intact? Prisoner 2: Yes. -
Cryptography Using Steganography: New Algorithms and Applications
Technological University Dublin ARROW@TU Dublin Articles School of Electrical and Electronic Engineering 2011 Cryptography Using Steganography: New Algorithms and Applications Jonathan Blackledge Technological University Dublin, [email protected] Follow this and additional works at: https://arrow.tudublin.ie/engscheleart2 Part of the Dynamic Systems Commons, and the Theory and Algorithms Commons Recommended Citation Blackledge, J. (2011) Cryptography and Steganography: New Algorithms and Applications. Lecture Notes, Centre for Advanced Studies, Warsaw University of Technology, Warsaw, 2011. doi:10.21427/D7ZS63 This Article is brought to you for free and open access by the School of Electrical and Electronic Engineering at ARROW@TU Dublin. It has been accepted for inclusion in Articles by an authorized administrator of ARROW@TU Dublin. For more information, please contact [email protected], [email protected], [email protected]. This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License Cryptography and Steganography: New Algorithms and Applications Prof. Dr. Jonathan Blackledge Science Foundation Ireland Stokes Professor School of Electrical Engineering Systems Dublin Institute of Technology Distinguished Professor Centre for Advanced Studies Warsaw University of Technology http://eleceng.dit.ie/blackledge http://jmblackledge.web.officelive.com [email protected] [email protected] Editor: Stanislaw Janeczko Technical editors: Malgorzata Zielinska, Anna Zubrowska General layout and cover design: Emilia Bojanczyk c Centre for Advanced Studies, Warsaw University of Technology, Warsaw 2011 For additional information on this series, visit the CAS Publications Website at http://www.csz.pw.edu.pl/index.php/en/publications ISBN: 978-83-61993-01-83 Pinted in Poland Preface Developing methods for ensuring the secure exchange of information is one of the oldest occupations in history. -
Rhyming Dictionary
Merriam-Webster's Rhyming Dictionary Merriam-Webster, Incorporated Springfield, Massachusetts A GENUINE MERRIAM-WEBSTER The name Webster alone is no guarantee of excellence. It is used by a number of publishers and may serve mainly to mislead an unwary buyer. Merriam-Webster™ is the name you should look for when you consider the purchase of dictionaries or other fine reference books. It carries the reputation of a company that has been publishing since 1831 and is your assurance of quality and authority. Copyright © 2002 by Merriam-Webster, Incorporated Library of Congress Cataloging-in-Publication Data Merriam-Webster's rhyming dictionary, p. cm. ISBN 0-87779-632-7 1. English language-Rhyme-Dictionaries. I. Title: Rhyming dictionary. II. Merriam-Webster, Inc. PE1519 .M47 2002 423'.l-dc21 2001052192 All rights reserved. No part of this book covered by the copyrights hereon may be reproduced or copied in any form or by any means—graphic, electronic, or mechanical, including photocopying, taping, or information storage and retrieval systems—without written permission of the publisher. Printed and bound in the United States of America 234RRD/H05040302 Explanatory Notes MERRIAM-WEBSTER's RHYMING DICTIONARY is a listing of words grouped according to the way they rhyme. The words are drawn from Merriam- Webster's Collegiate Dictionary. Though many uncommon words can be found here, many highly technical or obscure words have been omitted, as have words whose only meanings are vulgar or offensive. Rhyming sound Words in this book are gathered into entries on the basis of their rhyming sound. The rhyming sound is the last part of the word, from the vowel sound in the last stressed syllable to the end of the word. -
SOLVING CIPHER SECRETS Edited by M
SOLVING CIPHER SECRETS Edited by M. E. Ghaver INTERESTED FANS SEND IN SOME LIVELY CHAT-AND SEVERAL NEW PUZZLERS ARE OFFERED FOR HUNGRY HEADS ID you ever have trouble in occasionally, notwithstanding our combined solving some particular efforts to the contrary. cipher? And did you ever This, by way of introduction, fans, to a feel like running the party sort of " get-together " celebration that we ragged that contrived the have planned in this article. affair? It's just this way. So much has been Well, that's how Frank Spalding, of received from cipher enthusiasts in the way Wrangell, Alaska, must have felt about the of interesting questions, general comments, cipher of Foster F. V. Staples, in the June ciphers, and methods of solving them, that 6 " Solving Cipher Secrets." the only adequate way to cope with the sit• " If I could have caught him last night— uation, and thus to discharge this duty to June 7," writes Mr. Spalding, " he would our readers, is for us all to get together in have had to do some tall explaining." an entire article devoted to that purpose. Nevertheless, Mr. Spalding succeeded in So let's pull up our chairs and talk things solving this cipher, as well as all the others over. It may be that your particular ques• in that issue, although he confesses that tion will not crop up. Btit in that event when he had finished the lot he was " not a you will find another case that covers the good Christian any more!" same ground more completely. -
Cryptography
Cryptography Well, a gentle intro to cryptography. Actually, a fairly “hand-wavy” intro to crypto (we’ll discuss why) Fall 2018 CS 334: Computer Security 1 Special Thanks: to our friends at the Australian Defense Force Academy for providing the basis for these slides Fall 2018 CS 334: Computer Security 2 Definition • Cryptology is the study of secret writing • Concerned with developing algorithms which may be used: – To conceal the content of some message from all except the sender and recipient (privacy or secrecy), and/or – Verify the correctness of a message to the recipient (authentication or integrity) • The basis of many technological solutions to computer and communication security problems Fall 2018 CS 334: Computer Security 3 Terminology • Cryptography: The art or science encompassing the principles and methods of transforming an intelligible message into one that is unintelligible, and then retransforming that message back to its original form • Plaintext: The original intelligible message • Ciphertext: The transformed message • Cipher: An algorithm for transforming an intelligible message into one that is unintelligible Fall 2018 CS 334: Computer Security 4 Terminology (cont). • Key: Some critical information used by the cipher, known only to the sender & receiver – Or perhaps only known to one or the other • Encrypt: The process of converting plaintext to ciphertext using a cipher and a key • Decrypt: The process of converting ciphertext back into plaintext using a cipher and a key • Cryptanalysis: The study of principles -
Transposition Cipher in Cryptography, a Transposition Cipher Is a Method of Encryption by Which the Positions Held by Units of P
Transposition cipher In cryptography, a transposition cipher is a method of encryption by which the positions held by units of plaintext (which are commonly characters or groups of characters) are shifted according to a regular system, so that the ciphertext constitutes a permutation of the plaintext. That is, the order of the units is changed. Mathematically a bijective function is used on the characters' positions to encrypt and an inverse function to decrypt. Following are some implementations. Contents • 1 Rail Fence cipher • 2 Route cipher • 3 Columnar transposition • 4 Double transposition • 5 Myszkowski transposition • 6 Disrupted transposition • 7 Grilles • 8 Detection and cryptanalysis • 9 Combinations • 10 Fractionation Rail Fence cipher The Rail Fence cipher is a form of transposition cipher that gets its name from the way in which it is encoded. In the rail fence cipher, the plaintext is written downwards on successive "rails" of an imaginary fence, then moving up when we get to the bottom. The message is then read off in rows. For example, using three "rails" and a message of 'WE ARE DISCOVERED. FLEE AT ONCE', the cipherer writes out: W . E . C . R . L . T . E . E . R . D . S . O . E . E . F . E . A . O . C . A . I . V . D . E . N . Then reads off: WECRL TEERD SOEEF EAOCA IVDEN (The cipherer has broken this ciphertext up into blocks of five to help avoid errors.) Route cipher In a route cipher, the plaintext is first written out in a grid of given dimensions, then read off in a pattern given in the key. -
A Complete Bibliography of Publications in Cryptologia
A Complete Bibliography of Publications in Cryptologia Nelson H. F. Beebe University of Utah Department of Mathematics, 110 LCB 155 S 1400 E RM 233 Salt Lake City, UT 84112-0090 USA Tel: +1 801 581 5254 FAX: +1 801 581 4148 E-mail: [email protected], [email protected], [email protected] (Internet) WWW URL: http://www.math.utah.edu/~beebe/ 04 September 2021 Version 3.64 Title word cross-reference 10016-8810 [?, ?]. 1221 [?]. 125 [?]. 15.00/$23.60.0 [?]. 15th [?, ?]. 16th [?]. 17-18 [?]. 18 [?]. 180-4 [?]. 1812 [?]. 18th (t; m)[?]. (t; n)[?, ?]. $10.00 [?]. $12.00 [?, ?, ?, ?, ?]. 18th-Century [?]. 1930s [?]. [?]. 128 [?]. $139.99 [?]. $15.00 [?]. $16.95 1939 [?]. 1940 [?, ?]. 1940s [?]. 1941 [?]. [?]. $16.96 [?]. $18.95 [?]. $24.00 [?]. 1942 [?]. 1943 [?]. 1945 [?, ?, ?, ?, ?]. $24.00/$34 [?]. $24.95 [?, ?]. $26.95 [?]. 1946 [?, ?]. 1950s [?]. 1970s [?]. 1980s [?]. $29.95 [?]. $30.95 [?]. $39 [?]. $43.39 [?]. 1989 [?]. 19th [?, ?]. $45.00 [?]. $5.95 [?]. $54.00 [?]. $54.95 [?]. $54.99 [?]. $6.50 [?]. $6.95 [?]. $69.00 2 [?, ?]. 200/220 [?]. 2000 [?]. 2004 [?, ?]. [?]. $69.95 [?]. $75.00 [?]. $89.95 [?]. th 2008 [?]. 2009 [?]. 2011 [?]. 2013 [?, ?]. [?]. A [?]. A3 [?, ?]. χ [?]. H [?]. k [?, ?]. M 2014 [?]. 2017 [?]. 2019 [?]. 20755-6886 [?, ?]. M 3 [?]. n [?, ?, ?]. [?]. 209 [?, ?, ?, ?, ?, ?]. 20th [?]. 21 [?]. 22 [?]. 220 [?]. 24-Hour [?, ?, ?]. 25 [?, ?]. -Bit [?]. -out-of- [?, ?]. -tests [?]. 25.00/$39.30 [?]. 25.00/839.30 [?]. 25A1 [?]. 25B [?]. 26 [?, ?]. 28147 [?]. 28147-89 000 [?]. 01Q [?, ?]. [?]. 285 [?]. 294 [?]. 2in [?, ?]. 2nd [?, ?, ?, ?]. 1 [?, ?, ?, ?]. 1-4398-1763-4 [?]. 1/2in [?, ?]. 10 [?]. 100 [?]. 10011-4211 [?]. 3 [?, ?, ?, ?]. 3/4in [?, ?]. 30 [?]. 310 1 2 [?, ?, ?, ?, ?, ?, ?]. 312 [?]. 325 [?]. 3336 [?, ?, ?, ?, ?, ?]. affine [?]. [?]. 35 [?]. 36 [?]. 3rd [?]. Afluisterstation [?, ?]. After [?]. Aftermath [?]. Again [?, ?]. Against 4 [?]. 40 [?]. 44 [?]. 45 [?]. 45th [?]. 47 [?]. [?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?]. Age 4in [?, ?]. [?, ?]. Agencies [?]. Agency [?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?]. -
Jan. 2012 Issue
AmateurAmateur AA RR SS SocietySociety NewsNews Newsletter of The Amateur Radio Society of India (Member of IARU) English / Hindi Quarterly Volume I Issue 7 KARBIL/2009/38494 Jan. 2012 Price : Rs.10/- President’s message From the Editor’s desk Dear members all of us active hams are looking at Most of us were privileged to be a part learning more about. Here's wishing you all a HAPPY of Hamfest 2011 which was held in ARSI applied for and obtained special NEW YEAR 2012. More and more Kochi. It was an extremely well suffix for use by all Indian hams in amateurs are showing interest in organised and coordinated event with a commemoration of India's first HUGE gathering of hams and SWL's Formula 1 race meet at Greater Noida. working Satellites, so I have all having a chance to have an eyeball Many hams took an active part in the included a list of operational with their old friends and make new effort in running this most prestigious satellites along with the details. ones. The location and facilities were event. really great. Band conditions seems to be The propagation on the HF bands is improving – I expect a lot of activity The display and sales areas were just picking up nicely and we can hear and this year resulting in more news and like a major exhibition and there was work stations worldwide after a gap of space to move around and see what one some months. reports for me to include in the could pick up for homebrew efforts and newsletter, Hi Please send articles, augment one's shack.