Introduction to Cryptography - C839, Exam Questions and answers, rated A+

Introduction to Cryptography - C839, Exam Questions and answers, rated A+ Cryptography - -science of altering communication so that it cannot be understood without having the key Mono-Alphabet Substitution - -algorithms simply substitute one character of cipher text for each character of plain text. Caesar Cipher - -choose a number by which to shift each letter of a text. ATBASH Cipher - -Hebrew code substitutes first letter of alphabet for last, second letter for the second-to-the-last ROT13 Cipher - -characters rotated 13 characters Scytale - -Greek, written across leather, and wrapped around physical cylinder Substitution Weaknesses - -easy to break, preserve underlying letter and word frequency Multi-Alphabet Substitution - -use multiple alphabets, Cipher Disk - -Leon Alberti in 1466, polyalphabetic; Vigenère Cipher - -1553 by Giovan Battista; until early 1900s, multi-alphabet, 26X26 Playfair Cipher - -uses a 5 by 5 table containing a keyword or phrase encrypts two letters rather than one. ADFGVX - -36-letter alphabet; six-by-six square of letters, Enigma Machine - -Used In World War II the Germans; electromechanical rotor-based cipher system; SIGABA - -WWII American similar to the Enigma machine, but with improvements and more security. TypeX - -WWII British similar to the Enigma machine, but with improvements and more security.