Transposition Ciphers
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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. -
A Cipher Based on the Random Sequence of Digits in Irrational Numbers
https://doi.org/10.48009/1_iis_2016_14-25 Issues in Information Systems Volume 17, Issue I, pp. 14-25, 2016 A CIPHER BASED ON THE RANDOM SEQUENCE OF DIGITS IN IRRATIONAL NUMBERS J. L. González-Santander, [email protected], Universidad Católica de Valencia “san Vicente mártir” G. Martín González. [email protected], Universidad Católica de Valencia “san Vicente mártir” ABSTRACT An encryption method combining a transposition cipher with one-time pad cipher is proposed. The transposition cipher prevents the malleability of the messages and the randomness of one-time pad cipher is based on the normality of "almost" all irrational numbers. Further, authentication and perfect forward secrecy are implemented. This method is quite suitable for communication within groups of people who know one each other in advance, such as mobile chat groups. Keywords: One-time Pad Cipher, Transposition Ciphers, Chat Mobile Groups Privacy, Forward Secrecy INTRODUCTION In cryptography, a cipher is a procedure for encoding and decoding a message in such a way that only authorized parties can write and read information about the message. Generally speaking, there are two main different cipher methods, transposition, and substitution ciphers, both methods being known from Antiquity. For instance, Caesar cipher consists in substitute each letter of the plaintext some fixed number of positions further down the alphabet. The name of this cipher came from Julius Caesar because he used this method taking a shift of three to communicate to his generals (Suetonius, c. 69-122 AD). In ancient Sparta, the transposition cipher entailed the use of a simple device, the scytale (skytálē) to encrypt and decrypt messages (Plutarch, c. -
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IJCSI International Journal of Computer Science Issues, Vol. 10, Issue 4, No 2, July 2013 ISSN (Print): 1694-0814 | ISSN (Online): 1694-0784 www.IJCSI.org 89 An Eccentric Scheme for Oblivious Communication Khan Farhan Rafat and Muhammad Sher Department of Computer Science, International Islamic University Islamabad, 44000, Pakistan alphabets and then threading the yarn through these holes Abstract in an order which when detached spelt out letters of hidden Trust is the foremost requirement in any form of communication. message in its correct sequence [3]: Building trust through physical contact, gesture etc. is easy but hard to establish in electronic data communication as one can’t “padielaporsymesarponomeuaspeludynmalpreaxo” be sure of the presence of the intended recipient at the other end. “Ave Maria” is yet another smart method for encoding This necessitated the need to devise and suggest covert schemes secret message where list of distinct words for each unique for oblivious communication that only the intended recipient may alphabet are grouped in a series of Tables. For every unveil. Steganography is one such technique where information alphabet constituting the message, word corresponding to to be sent is seamlessly superimposed on the carrier such that it that letter from the set of Tables gets substituted and easily crosses the information confronting barriers without appeared as innocent rhyme whenever the Tables are used detection. This paper endeavors at evolving a data hiding scheme in sequence. envisaged by Shannon and in adherence to Kerchoff’s principle that hides secret information inside statistically random English Cardano introduced the “Grille System” [4] where every alphabets appearing as cryptogram. -
The Daily Egyptian, March 09, 1982
Southern Illinois University Carbondale OpenSIUC March 1982 Daily Egyptian 1982 3-9-1982 The aiD ly Egyptian, March 09, 1982 Daily Egyptian Staff Follow this and additional works at: https://opensiuc.lib.siu.edu/de_March1982 Volume 67, Issue 114 Recommended Citation , . "The aiD ly Egyptian, March 09, 1982." (Mar 1982). This Article is brought to you for free and open access by the Daily Egyptian 1982 at OpenSIUC. It has been accepted for inclusion in March 1982 by an authorized administrator of OpenSIUC. For more information, please contact [email protected]. Wrestling, water polo cut from sports By Steve MeeHl! student affairs. Both sports Swinburne said SIU-C will try SpIns E4II ... hltve finished their seasons and dual meets this season after a 9- records. He said makiDJ the to continue to offer the 7 record a year ago. The Swinburne said the cutback "diversity" in athletics it has cutback effective immediately The Inten:oUegiate Athletics takes effect immediately. WTP..atllll, program started at frees wrestlers to seek AcIvisM'y Committee Monday bad in the past. Sh] in 1950. HartzOl said droppiDl the two Hartzog said the dropping of scholarships at other schools. unanimously apPro~ed drop Hartzog said wrestling Coach sports would save aboUt 135.000. the two intercollegiate sports "This gives the opportunity to piDl water polo and wrestling which wiD be used to improve Linn LofII will not be left "high our two reaUy good Wrestlers to from the athletics program. was a "hard decision to make" and dry" by elimination of the men's athletin programs. -
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A Hybrid Cryptosystem Based on Vigenère Cipher and Columnar Transposition Cipher
International Journal of Advanced Technology & Engineering Research (IJATER) www.ijater.com A HYBRID CRYPTOSYSTEM BASED ON VIGENÈRE CIPHER AND COLUMNAR TRANSPOSITION CIPHER Quist-Aphetsi Kester, MIEEE, Lecturer Faculty of Informatics, Ghana Technology University College, PMB 100 Accra North, Ghana Phone Contact +233 209822141 Email: [email protected] / [email protected] graphy that use the same cryptographic keys for both en- Abstract cryption of plaintext and decryption of cipher text. The keys may be identical or there may be a simple transformation to Privacy is one of the key issues addressed by information go between the two keys. The keys, in practice, represent a Security. Through cryptographic encryption methods, one shared secret between two or more parties that can be used can prevent a third party from understanding transmitted raw to maintain a private information link [5]. This requirement data over unsecured channel during signal transmission. The that both parties have access to the secret key is one of the cryptographic methods for enhancing the security of digital main drawbacks of symmetric key encryption, in compari- contents have gained high significance in the current era. son to public-key encryption. Typical examples symmetric Breach of security and misuse of confidential information algorithms are Advanced Encryption Standard (AES), Blow- that has been intercepted by unauthorized parties are key fish, Tripple Data Encryption Standard (3DES) and Serpent problems that information security tries to solve. [6]. This paper sets out to contribute to the general body of Asymmetric or Public key encryption on the other hand is an knowledge in the area of classical cryptography by develop- encryption method where a message encrypted with a reci- ing a new hybrid way of encryption of plaintext. -
Grade 6 Math Circles Cryptography Solutions Atbash Cipher Caesar Cipher
Faculty of Mathematics Centre for Education in Waterloo, Ontario N2L 3G1 Mathematics and Computing Grade 6 Math Circles November 5/6 2019 Cryptography Solutions Hello World Khoor Zruog Hello Zruog Khoor Khoor Zruog World 1. Person A encrypts plaintext 2. Person B receives ciphertext 3. Person B decrypts ciphertext back into ciphertext into plaintext Atbash Cipher Examples 1. Encrypt \Math Circles" using the Atbash cipher. Nzgs Xrixovh 2. Decrypt \ORLM PRMT" using the Atbash cipher. LION KING Caesar Cipher Examples: Encrypt or decrypt the following messages using the shift number given in parentheses: a) Welcome to Math Circles! (5) Bjqhtrj yt Rfym Hnwhqjx! plaintext A B C D E F G H I J K L M N O P Q R S T U V W X Y Z ciphertext F G H I J K L M N O P Q R S T U V W X Y Z A B C D E 1 b) Ljw hxd anjm cqrb? (9) Can you read this? plaintext A B C D E F G H I J K L M N O P Q R S T U V W X Y Z ciphertext J K L M N O P Q R S T U V W X Y Z A B C D E F G H I c) What if I did a Caesar Shift of 26 units on \Welcome to Math Circles!"? A Caesar shift of 26 would be shifting by the length of the alphabet. For example I would be shifting A 26 letters to the right. -
Alaska Department of Fish and Game Staff Comments on Commercial Regulatory Proposals for the Statewide King and Tanner Crab Meeting
RC 2 ALASKA DEPARTMENT OF FISH AND GAME STAFF COMMENTS ON COMMERCIAL, PERSONAL USE, SPORT, AND SUBSISTENCE REGULATORY PROPOSALS FOR STATEWIDE (EXCEPT SOUTHEAST AND YAKUTAT) KING AND TANNER CRAB AND SUPPLEMENTAL ISSUES ALASKA BOARD OF FISHERIES MEETING ANCHORAGE, ALASKA MARCH 8–11, 2020 Revised 02/24/20 with the addition of Proposal 284 Regional Information Report No. 5J20-03 The following staff comments were prepared by the Alaska Department of Fish and Game (department) for use at the Alaska Board of Fisheries (board) meeting, March 8–11, 2020 in Anchorage, Alaska. The comments are forwarded to assist the public and board. The comments contained herein should be considered preliminary and subject to change, as new information becomes available. Final department positions will be formulated after review of written and oral public testimony presented to the board. Acronyms and Abbreviations The following acronyms and abbreviations, and others approved for the Système International d'Unités (SI), are used without definition in the following reports by the Divisions of Commercial Fisheries, Sport Fish, and Subsistence: All others, including deviations from definitions listed below, are noted in the text at first mention, as well as in the titles or footnotes of tables, and in figure or figure captions. Weights and measures (metric) General Acronyms centimeter cm Alaska Administrative Acceptable Biological Catch ABC deciliter dL Code AAC Alaska Board of Fisheries board gram g all commonly accepted Alaska Department of Fish department hectare ha abbreviations e.g., Mr., Mrs., and Game /ADF&G kilogram kg AM, PM, etc. kilometer km all commonly accepted Amount Necessary for liter L professional titles e.g., Dr., Ph.D., Subsistence ANS meter m R.N., etc. -
The Solving of a Fleissner Grille During an Exercise by the Royal Netherlands Army in 1913
The Solving of a Fleissner Grille during an Exercise by the Royal Netherlands Army in 1913 Karl de Leeuw University of Amsterdam / Informatics Institute Science Park 904, 1098 XH Amsterdam [email protected] Abstract Initially the grille was intended for hiding that a secret message was being sent at all, rather than In 1885 the General Staff of the Royal as a means of encryption. This all changed dur- Netherlands Army had adopted a variant ing the course of the 18th century, when the grille of the turning grille devised by Edouard was increasingly used for jumbling the characters Fleissner von Wostrowitz as a means for in a message by rotating them, according to the encrypting messages, exchanged by tele- holes in the mask. The first description of such graph between the General Headquarters use we find by the German mathematician Carl and commanders in the field. Some staff Friedrich von Hindenburg (1796) who was aware members harbored serious doubts about that such use could only be made at the expense the security of this device, however, and of a loss in entropy and, therefore, cryptographic during a military exercise in 1913 it was strength. The perforation pattern in one quadrant solved with surprising ease by an army of the mask would automatically limit the possi- captain. The matter was investigated by bilities for perforation in all others, because two a committee of staff officers, concluding punch holes could not be allowed to cover the that the army lacked the expertise to judge same position after a rotation. -
Breaking Transposition Cipher with Genetic Algorithm
Breaking Transposition Cipher with Genetic Algorithm C.Obi Reddy, National University of Singapore(NUS), ECE Department, [email protected] Abstract: In recent years a number of example total number of letters is 20 optimisation algorithms have emerged which is regular case with the key order of which have proven to be effective in 5. If the plain text is irregular then solving a variety of NP-complete padding of X is done at the tail of the text problems. In this paper an example the to make it regular. kind in cryptanalysis, breaking of Encryption of plain text is done as follows transposition cipher using a heuristic genetic algorithm is presented. Regular: Plain 1 2 3 4 5 Introduction: Text In the Brute Force attack the attacker Key 1 4 2 5 3 tries every possible (k! Keys) key on a T H I S I piece of cipher text until an intelligible S A S I M translation into plaintext is obtained. P L E M E Many types of classical ciphers exist, S S A G E although most fall into one of two broad categories: substitution ciphers and Cipher Text: TSPS ISEA IMEE HALS SIMG transposition ciphers. In the former one, every plaintext character is substituted by Irregular: a cipher character, using a substitution Plain 1 2 3 4 5 alphabet, and in the latter one, plaintext Text characters are permuted using a Key 1 4 2 5 3 predetermined permutation. T H I S I S A S I M Transposition cipher works by breaking P L E M E the plain text in to fixed number of blocks S S A G E and then shuffling the characters in each block according to the agreed key K. -
Lecture 2: Classical Cryptography
Lecture 2: Classical Cryptography Data and Information Management: ELEN 3015 School of Electrical and Information Engineering, University of the Witwatersrand Introduction Monoalphabetic Cipher - Frequency analysis Classical Ciphers Other Substitution Ciphers Transposition ciphers Stream vs Block Enciphering 1. Homework hqfubswlrq lv d phdqv ri dwwdlqlqj vhfxuh frpsxwdwlrq ryhu lqvhfxuh fkdqqhov eb xvlqj hqfubswlrq zh glvjxlvh wkh phvvdjh vr wkdw hyhq li wkh wudqvplvvlrq lv glyhuwhg wkh phvvdjh zloo qrw eh uhyhdohg 1. Monoalphabetic Cipher - Frequency analysis Do a frequency analysis Letter distribution of English language is fixed (for a large body of text) Tables of letter distribution For instance, most commonly used letter is \e" 1. Monoalphabetic Cipher - Frequency analysis 1. Monoalphabetic Cipher - Answer ENCRYPTION IS A MEANS OF ATTAINING SECURE COMMUNICATION OVER INSECURE CHANNELS BY USING ENCRYPTION WE DISGUISE THE MESSAGE SO THAT EVEN IF THE TRANSMISSION IS DIVERTED THE MESSAGE WILL NOT BE REVEALED 2. Classical Ciphers How do we increase security of the monoalphabetic cipher? 3. Polyalphabetic ciphers Use more than one alphabetic substitution to flatten the frequency distribution Combine substitutions that are high with those that are low Eg use: • P1(a) = (a*3)mod26 • P2(a) = ((5*a)+13)mod26 3. Polyalphabetic ciphers Cipher I: ABCDEFG ::: STUVWXYZ a d g j m p s ::: c f i l o r u x Cipher II: ABCDEFG ::: STUVWXYZ n s x c h m r ::: z e j o t y d i 3. Polyalphabetic ciphers - Frequency distribution 3. Vigenere tables a b c d e f ::: t u v w x y z π A a b c d e f ::: t u v w x y z 0 B b c d e f g ::: u v w x y z a 1 C c d e f g h ::: v w x y z a b 2 .