About this Study Set
This study set covers Cryptography through
25 practice questions.
A collection of factual questions covering the history and mechanics of codes, ciphers, and cryptographic systems. Every question includes the correct answer so you can learn as you go — pick any format above to get started.
Questions & Answers
Browse all 25 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 World War II German cipher machine used a series of rotating wheels to scramble messages?
-
A
Enigma
-
B
Purple
-
C
Lorenz
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D
Typex
2
What is the oldest known method of encryption, involving shifting letters in the alphabet by a set number of positions?
-
A
Vigenere cipher
-
B
Caesar cipher
-
C
Playfair cipher
-
D
Rail fence cipher
3
Which polyalphabetic substitution cipher uses a keyword to determine the shift for each letter?
-
A
Atbash cipher
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B
Vigenere cipher
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C
Bacon's cipher
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D
ROT13
4
What was the primary goal of the 'SIGABA' machine used by the United States during World War II?
-
A
Radio signal jamming
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B
Secret communication
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C
Radar calibration
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D
Map encryption
5
The 'Zimmermann Telegram' was a decoded message sent by Germany to which country during World War I?
-
A
France
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B
Russia
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C
Mexico
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D
Japan
6
Which famous cryptanalyst led the team at Bletchley Park that cracked the Enigma code?
-
A
Alan Turing
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B
Claude Shannon
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C
Charles Babbage
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D
Ada Lovelace
7
What type of cipher replaces each letter with its mirror image in the alphabet (A becomes Z, B becomes Y)?
-
A
Affine cipher
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B
Atbash cipher
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C
Beaufort cipher
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D
Null cipher
8
Which historical codebreaking device was the first electromechanical machine used to attack the Enigma?
-
A
Colossus
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B
The Bombe
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C
Differential Analyzer
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D
Difference Engine
9
What is the term for the process of converting plaintext into ciphertext?
-
A
Decryption
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B
Hashing
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C
Encryption
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D
Steganography
10
Which American cryptographer is credited with coining the term 'information theory'?
-
A
Bruce Schneier
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B
Claude Shannon
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C
Whitfield Diffie
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D
Phil Zimmermann
11
The 'Great Cipher' was a highly secure system used by which French monarch?
-
A
Louis XIV
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B
Napoleon Bonaparte
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C
Charles X
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D
Francis I
12
What is the name of the modern cryptographic system that uses a pair of keys (public and private)?
-
A
Symmetric key cryptography
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B
Asymmetric cryptography
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C
Substitution cryptography
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D
Transposition cryptography
13
Which World War I cipher was famous for its use of a 5x5 grid of letters?
-
A
Playfair cipher
-
B
Hill cipher
-
C
Polybius square
-
D
Bifid cipher
14
What term describes the practice of hiding a secret message within a non-secret file, such as an image?
-
A
Steganography
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B
Cryptography
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C
Cryptanalysis
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D
Ciphertext
15
The 'Purple' code was a diplomatic cipher used by which country during the 1930s and 1940s?
-
A
Italy
-
B
Germany
-
C
Japan
-
D
Spain
16
What is the primary function of a 'hash' function in computer security?
-
A
Encryption of data
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B
Compression of files
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C
Verification of data integrity
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D
Masking of IP addresses
17
Which historical cipher is based on the principle of writing a message in a zig-zag pattern?
-
A
Rail fence cipher
-
B
Columnar transposition
-
C
Scytale
-
D
Book cipher
18
The 'Scytale' cipher, used by the ancient Spartans, relied on which object to read the message?
-
A
A stone slab
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B
A rotating cylinder
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C
A wooden baton
-
D
A wax tablet
19
What is the standard length of an MD5 hash value in bits?
-
A
64 bits
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B
128 bits
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C
256 bits
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D
512 bits
20
Which historical group of people used a cipher based on the position of dots and dashes in a grid?
-
A
Knights Templar
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B
Freemasons
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C
Rosicrucians
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D
Carbonari
21
What does the acronym 'RSA' stand for in public-key cryptography?
-
A
Rivest, Shamir, Adleman
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B
Random Security Algorithm
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C
Robust Secure Architecture
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D
Remote System Access
22
In cryptography, what is a 'key'?
-
A
A physical lock
-
B
A piece of information used by a cipher
-
C
A sequence of random numbers
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D
A protocol for communication
23
Which of these is a substitution cipher that uses a 2x2 matrix to transform pairs of letters?
-
A
Hill cipher
-
B
Vigenere cipher
-
C
Playfair cipher
-
D
Baconian cipher
24
What was the name of the British codebreaking computer used to crack the Lorenz cipher?
-
A
Enigma
-
B
Colossus
-
C
Bombe
-
D
Turing machine
25
What is the defining characteristic of a 'monoalphabetic' cipher?
-
A
It uses a single key for all letters
-
B
It uses multiple alphabets for encryption
-
C
Each letter is replaced by a consistent substitute
-
D
It requires a computer to decode
