Substitution ciphers

Number of keys used in symmetric key encryption are

• 1

• 2

• 3

• 4

Based on the type of operation used for transforming plaintext to ciphertext, cryptography can be classified as

• Substitution Cipher

• Transposition Cipher

• Block Cipher

• Stream Cipher

Encryption is a process of converting ciphertext to plaintext

• True

• False

Decryption process requires ________ to convert ciphertext back to plaintext

Internet is a ________ channel to exchange information

• Secure

• Insecure

• Multipurpose

In Classical Caesar Cipher key is

• 1

• 2

• 3

• 4

Key space of Caesar Cipher is

• 3

• 20

• 13

• 25

Trying all possible keys by an adversary is known as

• Staistical Attack

• Brute-Force Attack

• Correlation attack

• None

One to one mapping is present in __________ Ciphers

• Caesar

• Playfair

• Hill

• Manoalphabetic

Block cipher uses different key to encrypt all the blocks

• True

• False