Cryptography Quiz

What is the key square in the Playfair Cipher?

• 6x6 matrix

• 5x5 matrix

• 3x3 matrix

• 4x4 matrix

In the Playfair Cipher, what should be done if there are any double letters in the plaintext when dividing into digraphs?

• Add letter 'x'

• Add letter 'y'

• Add letter 'w'

• Add letter 'z'

Which case in the Playfair Cipher decryption involves considering the letters left of each alphabet if both letters are in the same row?

• Case I

• Case II

• Case III

• None of the above

What is the advantage of the Playfair Cipher mentioned in the text?

• Requires a Playfair cipher calculator

• Easy to Decrypt

• Requires less ciphertext for frequency analysis

• Uses different keys for encryption and decryption

What type of cipher is the Affine Cipher?

• Stream cipher

• Transposition cipher

• Polyalphabetic substitution cipher

• Monoalphabetic substitution cipher

What is the mathematical function used in the encryption process of the Affine Cipher?

• E(x) = (ax + b) mod m

• E(x) = (ax - b) mod m

• E(x) = (ax * b) mod m

• E(x) = (a + b) mod m

How is the decryption process of the Affine Cipher usually done?

• By using the same key as encryption

• By directly reversing the encryption function

• By finding the inverse of 'a' through brute-forcing

• By using a different key than encryption

What is the disadvantage of the Playfair Cipher mentioned in the text?

• Not useful for high data volume

• Uses a different key for each letter

• Uses different keys for encryption and decryption

• Requires a Playfair cipher calculator

What is the size of the alphabet usually used in the Affine Cipher?

• 20

• 26

• 30

• 32

In the Playfair Cipher, what should be done if there are any characters or punctuation not present in the key square?

• Add them to the key square

• Remove them

• Replace them with 'z'

• Replace them with 'x'