Cryptography questions

By Interwoven Maths

Cryptography question collection

Review Cryptography questions for Computer Science, with correct answers shown and coverage across encryption and decryption; ciphers and keys; secure communication.

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Question 1

What is cryptography?
  1. Protecting information by encoding it
  2. Building computer hardware
  3. Creating spreadsheet formulas
  4. Connecting network cables

Question 2

What is plaintext?
  1. The original readable message
  2. A public key
  3. A compressed file
  4. A binary image

Question 3

What is ciphertext?
  1. The encrypted message
  2. The original unencrypted message
  3. A network address
  4. A chart label

Question 4

What does encryption convert?
  1. Plaintext to ciphertext
  2. Ciphertext to plaintext
  3. Text to image
  4. Binary to decimal

Question 5

What does decryption convert?
  1. Ciphertext to plaintext
  2. Plaintext to ciphertext
  3. Image to audio
  4. Data to formulas

Question 6

What is a key in cryptography?
  1. A value used to encrypt or decrypt
  2. A USB connector
  3. A spreadsheet column
  4. A browser tab

Question 7

How does a Caesar cipher work?
  1. By shifting letters by a fixed amount
  2. By sorting letters alphabetically
  3. By deleting every vowel
  4. By converting words to numbers only

Question 8

With a Caesar shift of 1, what does A become?
  1. B
  2. Z
  3. C
  4. 1

Question 9

What does a substitution cipher do?
  1. Replaces letters with other letters or symbols
  2. Removes all spaces only
  3. Uses no key at all
  4. Always uses binary shifts

Question 10

What does frequency analysis use?
  1. Patterns in letter frequency
  2. CPU temperature data
  3. Battery level data
  4. Screen resolution values

Question 11

The Enigma machine was used in which war?
  1. World War II
  2. The 1990s web era
  3. The first smartphone launch
  4. Victorian schools

Question 12

Where was Enigma cracked?
  1. Bletchley Park
  2. Silicon Valley
  3. NASA Houston
  4. MIT Lab

Question 13

What is Alan Turing best known for?
  1. Helping to break Enigma
  2. Inventing HTML
  3. Creating SQL
  4. Designing SSDs

Question 14

What does a Vigenere cipher use?
  1. A keyword to vary letter shifts
  2. One fixed shift only
  3. No shifts at all
  4. Only numeric keys

Question 15

What does symmetric encryption use?
  1. The same key for encrypting and decrypting
  2. No keys at all
  3. Two public keys
  4. Two private keys only

Question 16

What does asymmetric encryption use?
  1. A public/private key pair
  2. A single shared key
  3. A username only
  4. A MAC address

Question 17

What is RSA an example of?
  1. Asymmetric encryption
  2. A Caesar cipher
  3. A spreadsheet function
  4. A binary sorting algorithm

Question 18

How does HTTPS protect web traffic?
  1. By encrypting it
  2. By compressing images
  3. By adding extra RAM
  4. By using local caching only

Question 19

What is phishing?
  1. Fake messages used to steal information
  2. A type of hard drive
  3. A data compression method
  4. A programming language

Question 20

What does ransomware do?
  1. Locks files and demands payment
  2. Speeds up quizzes
  3. Improves Wi-Fi signal
  4. Adds spreadsheet charts

Question 21

What is a brute-force attack?
  1. Trying many possible keys until one works
  2. Replacing each letter with a symbol once
  3. Sending plaintext with no key
  4. Sharing a private key publicly

Question 22

What does a hash function produce?
  1. A fixed-length hash value
  2. A reversible encrypted message
  3. A public/private key pair
  4. A compressed image file

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Review Cryptography questions for Computer Science, with correct answers shown and coverage across encryption and decryption; ciphers and keys; secure communication.

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