Codebusters Test Codebusters Cryptography Theory and History 4

Question 1

Who is known as the 'father of the NSA' and made seminal contributions to information theory and cryptography?

Accepted Answer

Claude Shannon

Answer

Alan Turing

Answer

Whitfield Diffie

Answer

Martin Hellman

Question 2

The Diffie-Hellman key exchange, published in 1976, introduced which revolutionary concept to cryptography?

Accepted Answer

Public-key (asymmetric) cryptography

Answer

Symmetric encryption

Answer

The one-time pad

Answer

Digital signatures only

Question 3

During World War II, the Allied codebreakers at Bletchley Park who broke ENIGMA were led by which mathematician?

Accepted Answer

Alan Turing

Answer

Bertrand Russell

Answer

John von Neumann

Answer

Norbert Wiener

Question 4

The Caesar cipher is an example of which specific cipher type?

Accepted Answer

ROT cipher / shift cipher

Answer

Keyword substitution

Answer

Affine cipher

Answer

Atbash cipher

Question 5

The Atbash cipher, originating in Hebrew tradition, works by:

Accepted Answer

Mapping each letter to its mirror image in the alphabet (A↔Z, B↔Y, etc.)

Answer

Reversing the order of words in a message

Answer

Substituting every letter with the one 13 positions later

Answer

Encrypting with a keyword derived from the Torah

Question 6

ROT13 is a special case of which cipher, and why is it notable?

Accepted Answer

Caesar cipher; notable because encoding and decoding use the same operation

Answer

Vigenère cipher; notable because it uses 13 keywords

Answer

Playfair cipher; notable because it handles all 26 letters equally

Answer

Beaufort cipher; notable because it is self-inverse for odd-length messages

Question 7

Which 9th-century Arab scholar wrote 'A Manuscript on Deciphering Cryptographic Messages,' the first known treatise on frequency analysis?

Accepted Answer

Al-Kindi

Answer

Al-Khwarizmi

Answer

Ibn Sina

Answer

Al-Biruni