About this Study Set
This study set covers Cryptography through
18 practice questions.
An introduction to the history, methods, and terminology of codes and ciphers. Every question includes the correct answer so you can learn as you go — pick any format above to get started.
Questions & Answers
Browse all 18 questions from the
Fundamentals of Cryptography study set below.
Each question shows the correct answer — select a study format above to practice interactively.
1
Which type of cipher replaces each letter in the plaintext with a fixed letter a certain number of positions down the alphabet?
-
A
Caesar cipher
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B
Vigenère cipher
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C
Transposition cipher
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D
Rail fence cipher
2
What is the term for the original, readable message before it is encrypted?
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A
Ciphertext
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B
Plaintext
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C
Key
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D
Algorithm
3
The Enigma machine, used for encryption during World War II, was primarily operated by which nation?
-
A
United Kingdom
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B
United States
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C
Germany
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D
Japan
4
Which classic cipher uses a keyword to determine a series of different Caesar ciphers based on the letters of the keyword?
-
A
Atbash cipher
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B
Vigenère cipher
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C
Playfair cipher
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D
Scytale cipher
5
In cryptography, what is a 'key'?
-
A
A physical metal object
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B
A piece of information that controls the encryption process
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C
A type of computer virus
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D
The final encrypted message
6
Which ancient Greek device consisted of a cylinder wrapped with a strip of parchment to encrypt messages?
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A
Abacus
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B
Astrolabe
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C
Scytale
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D
Antikythera mechanism
7
What is the process of converting encrypted data back into its original, readable form?
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A
Encoding
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B
Decoding
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C
Decryption
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D
Transposition
8
The 'Atbash' cipher is a simple substitution cipher that works by reversing which of the following?
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A
The entire alphabet
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B
The word order
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C
The sentence structure
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D
The frequency of vowels
9
Which field of study involves the practice and study of techniques for secure communication in the presence of third-party adversaries?
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A
Cryptography
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B
Calligraphy
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C
Cartography
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D
Cryptology
10
In the context of the World War II era, who led the team at Bletchley Park that successfully cracked the Enigma code?
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A
Charles Babbage
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B
Alan Turing
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C
Ada Lovelace
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D
John von Neumann
11
What is a cipher called if it changes the position of the letters in the message rather than substituting them for other letters?
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A
Substitution cipher
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B
Transposition cipher
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C
Polyalphabetic cipher
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D
Monoalphabetic cipher
12
Which technique involves analyzing the frequency of letters in a ciphertext to break simple substitution ciphers?
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A
Frequency analysis
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B
Brute force
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C
Key exchange
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D
Steganography
13
What term describes the practice of hiding a secret message within a non-secret file, such as an image or audio track?
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A
Encryption
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B
Cryptography
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C
Steganography
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D
Hashing
14
Which of the following is an example of a symmetric-key algorithm?
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A
RSA
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B
AES
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C
Diffie-Hellman
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D
ECC
15
What is the primary vulnerability of a simple Caesar cipher?
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A
It requires a computer
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B
It has a very small number of possible keys
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C
It cannot be written down
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D
It only works on vowels
16
During World War I, the Zimmermann Telegram was an intercepted message that influenced which country to join the war?
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A
Australia
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B
Canada
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C
United States
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D
France
17
A 'Polyalphabetic' cipher is one that uses:
-
A
Only one substitution alphabet
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B
Multiple substitution alphabets
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C
No alphabet at all
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D
Only prime numbers
18
What is 'brute force' in the context of cracking a code?
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A
Using physical force to open a safe
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B
Trying every possible key until the correct one is found
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C
Using a supercomputer to analyze language patterns
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D
Stealing the key from the sender
