WGU C839 OBJECTIVE ASSESSMENT FINAL WGU C839 INTRODUCTION TO CRYPTOGRAPHY NEWEST COMPLETE 400 QUESTI

get pdf at;https://learnexams.com/ .WGU C839 OBJECTIVE ASSESSMENT FINAL/WGU C839 INTRODUCTION TO CRYPTOGRAPHY NEWEST 2024-2025 COMPLETE 400 QUESTIONS AND CORRECT DETAILED ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED A+||BRAND NEW!! A ________________ is one in which you know both the plaintext and the ciphertext. The most obvious goal is to find the decryption key. - ANSWER- known-plaintext attack A known-plaintext attack is more powerful than a ciphertext- only attack. A True B False - ANSWER- A A __________________ is any nontrivial method that detects a difference between the ideal encryption scheme and the actual one. This covers all the attacks we have discussed so far, as well ,2|Page as any yet-to-be-discovered attacks. - ANSWER- distinguishing attack A ____________________is an attack that depends on the fact that duplicate values, also called collisions, appear much faster than you would expect. - ANSWER- Birthday attack An __________________ attack is one that tries all possible values for some target object, like the key. If an attack requires 2^235 steps of work, then this corresponds to an exhaustive search for a 235-bit value. - ANSWER- exhaustive search First introduced by Eli Biham in 1993, a ___________ attack assumes that the attacker has access to several encryption functions. These functions all have an unknown key, but their keys have a relationship that the attacker knows. - ANSWER- related-key A _____________ cipher is one for which no attack exists. - ANSWER- secure block An attack on a block cipher is a non-generic method of distinguishing the block cipher from an ______________ cipher. - ANSWER- ideal block ,3|Page Most modern block ciphers have a ________ block size, but they operate on 32-bit words. - ANSWER- 128-bit An _____________ cipher implements an independently chosen random even permutation for each of the key values. - ANSWER- ideal block The simplest method to encrypt a longer plaintext is known as the _______________________. It has serious weakness, therefore, do not use this method. - ANSWER- electronic codebook mode (ECB) _____________________ was a cylinder tool used by the Greeks, and is often specifically attributed to the Spartans. It was a physical cylinder that was used to encrypt messages. Turning the cylinder produced different ciphertexts. While it is not clear exactly how old this cipher is, it was first mentioned in the 7th century BC by the Greek poet Archilochus. The recipient uses a rod of the same diameter as the one used to create the message. He then wraps the parchment to read the message. To encrypt, one simply writes across the leather. - ANSWER- Scytale Caesar Cipher - Every letter is shifted a fixed number of spaces to the left or the right in the alphabet. The reason it is easy to crack is the issue of letter and word frequency. , 4|Page Atbash Cipher - is a Hebrew code, easier to crack than Caesar, which substitutes the first letter of the alphabet for the last and the second letter for the second to the last, etc. It simply reverses the alphabet Used by Hebrew scribes copying the book of Jeremiah. Example: A becomes Z, B becomes Y, C becomes X, etc. Affine Cipher - is any single-substitution alphabet cipher (also called mono-alphabet substitution) in which each letter in the alphabet is mapped to some numeric value, permuted with some relatively simple mathematical function, and then converted back to a letter. The formula for Affine is: ax + b (mod M). M=26, x=Plaintext numerical equivalent, b=the shift, a=some multiple. For Caesar a=1. Rot13 Cipher - is another sing - ANSWER- Examples of Mono- Alphabet Substitution Homophonic substitution was one of the earlier attempts to make substitution ciphers more robust by_________ the letter frequencies. - ANSWER- masking In World War II, the Germans used this as an electromechanical rotor-based cipher system. The machine was designed so that