WGU D334 INTRODUCTION TO CRYPTOGRAPHY - REAL EXAM QUESTIONS VERIFIED 100% CORRECT

Terms in this set (250) XOR the following asymmetric key-based encryption -typical methods RSA DSA El Gamal Symmetric key-based encryption -Typical Methods RC2- 40 bit key size 64 bit block RC4- (Stream Cipher)- Used in SSL and WEP RC5- (Variable Key size, 32, 64, or 128 bit block size) AES- (128, 192 or 256 bit key size, 128 bit block size) DES- (56 bit key size. 64 bit Block size) 3DES- (112 bit key size, 64 bit block size) Block Encryption RC2(40 bit key size) RC5(Variable block size) IDEA DES 3DES AES (Rijndael) Blowfish twofish stream encryption RC4 Chacha Rainbow Attack The method of knowing the mapping between the hashed values and the original data Dictionary-type attack a brute force analysis ∉ does not belong to when an object is not in a set ∈ Belongs to when an object is within a set ⊆ subset subset has fewer elements or equal to the set A ∪ B union (objects that belong to set A or set B) | such that A ∩ B Intersection: in both A and B Enigma Machine -Cypher 10 Used a polyalphabetic substitution cipher, which did not repeat within a reasonable time period, along with a secret key. For the cracking of the Enigma cipher, the challenge was thus to determine both the algorithm used and the key. Enigma's main weakness, though, was that none of the plain text letters could be ciphered as itself. Four-square cipher9 Uses four 5 × 5 matrices arranged in a square, are where each matrix contains 25 letters for encoding and decoding operations. One-time pad cypher8 Cypher Code mapping that is only used once. Advantage: it is essentially unbreakable. Disadvantage: it takes lots of work as you would have to generate the pad to be used, each time. Vigenere Cipher 7 Polyalphabetic cipher that involves using a different mapping, based on a keyword, for each character of the cipher. An advantage of this type of cipher is that the same plaintext character is likely to be coded to different mappings, depending on the position of the keyword, making guessing more difficult. Ceasar Cipher6 Mono-alphabetic substitution cipher known as "shift" cipher. Involves plaintext being replaced by a letter some fixed number of positions down the alphabet. i.e., a Caesar Cipher using a shift of +3 would mean a plaintext letter A would result in a ciphertext letter D (a shift of three positions to the right in the alphabet) Morse Code cipher 5 Encoding method, rather than a cipher, that works by translating characters into sequences of dots (.) and dashes (-) Playfair Cipher 4 5 × 5 matrix containing the alphabet less the letter J. Cipher/decipher process consists of a set of rules outlining use of column and row combinations. BIFID Cipher 3 Makes use of a grid and which maps the letters into numeric values. Rail Code Cipher 2 Employs a method to scramble text by writing it in a sequence across a number of rails. Pig Pen Cipher 1 Mono- alphabetic substitution cipher that makes use of mapping plaintext characters to graphical characters rather than to alphabetic ones. i.e. A=(pick a symbol), vs A=(pick a letter). Disadvantage: once the mapping is known, it is difficult to keep the message secret. Encryption in simplest terms is changing plaintext into ciphertext Decryption The process of converting a ciphertext into plaintext. AESCrypt Encrypt individual files and encrypt full disks with options such as Bitlocker and FileVault Mono-alphabetic c code or substitution is where a single mapping from our alphabet to a cipher alphabet is created. Many early cryptosystems used this. Polyalphabetic refers to the mapping of our alphabet to a number of cipher alphabets. This approach added a bit of complexity to early cryptosystems. One-time pad is considered to be unbreakable since it only uses its cipher code once. Pseudo-Random Number Generators (PRNGs) This method repeats the random numbers after a given time (periodic). They are fast and are also deterministic and are useful in producing a repeatable set of random numbers. Frequency Analysis is cipher cracking methodology that involves identifying patterns and variations in the probability of codes. i.e. a three-letter ciphered text combination spotted at the beginning of a string too often could tip us off that those three letters correlate the letters THE in the English alphabet.