INTRO TO CRYPTOGRAPHY WGU C839 MODULE 2 QUESTIONS AND ANSWERS WITH SOLUTIONS 2025

The same key is used to encrypt messages as well as decrypt messages. These algorithms are always faster but have an issue with exchanging keys. - ANSWER Symmetric Cryptography Modern cryptography began when Claude Shannon publish "Communication Theory of Secrecy Systems" in 1949. He focused on this concept by quantifying information, leading to a number of methods for encrypting and decrypting information. - ANSWER Information Theory Change to one character in plain text affect multiple characters in the cipher text. - ANSWER Diffusion Attempts to make the relationship between statistical frequencies of the cipher text and the actual key as complex as possible. Uses complex substitution algorithms. - ANSWER Confusion A small change yields large effects in the output. Fiestel's variation on Claude Shannon's concept of diffusion. Ideally, a change in one bit of plaintext would change all the bits in the ciphertext. - ANSWER Avalanche A cryptosystem should be secure even if everything about the system, except the key, is publicly known. - ANSWER Kerckhoffs's Principle C = E(k,p) expresses what mathematically? - ANSWER Symmetric Algorithm for Encryption P = D(k,c) expresses what mathematically? - ANSWER Symmetric Algorithm for Decryption Changing some part of the plain text for some matching part of the cipher text is? - ANSWER Substitution Swapping of blocks of cipher text. given a sentence "I like icecream" you co