What is the key shift in a Caesar cipher if the key is 3?

• 3 positions diagonal in the alphabet

• 1 position forward in the alphabet

• 3 positions forward in the alphabet

• 3 positions backward in the alphabet

Which cipher uses a keyword to determine the letter substitution?

• Caesar cipher

• Vigenère cipher

• Transposition cipher

• Substitution cipher

In a Vigenère cipher, what is the length of the repeating key if the key is 'KEY'?

• 5

• 4

• 3

• 2

What is the main characteristic of a Vernam cipher?

• It encrypts data using a fixed key.

• It uses a one-time pad for encryption.

• It uses a symmetric key for encryption.

• It relies on a public key infrastructure.

Which cipher is considered unbreakable when used correctly?

• Caesar cipher

• RSA encryption

• Vigenère cipher

• one-time pad

In a Playfair cipher, how are duplicate letters handled?

• Duplicate letters in a digraph are handled by replacing the second letter with a filler letter, usually 'X'.

• Duplicate letters are combined into a single letter.

• Duplicate letters are ignored entirely.

• Duplicate letters are replaced with the next letter in the alphabet.

What is the primary method of encryption in a Rail Fence cipher?

• Zigzag pattern across multiple rails

• Substitution of letters

• Straight line encryption

• Transposition of words

How many rows are used in a Rail Fence cipher with a depth of 3?

• 5

• 3

• 2

• 4

What is the formula for the number of possible keys in a one-time pad?

• n!

• 2^n

• n^2

• 2n

In an Autokey cipher, what is the role of the plaintext?

• The plaintext is used to generate the keystream for encryption.

• The plaintext is used to create a static key for encryption.

• The plaintext serves as the final output of the cipher.

• The plaintext is encrypted directly without modification.