Cryptography and Network Security - Unit 1

Which of the following is NOT a security service as per OSI Security Architecture?

• a) Data Confidentiality

• b) Authentication

• c) Integrity

• d) Protocol Control

What does the OSI security architecture primarily define?

• a) Physical Layer Security

• b) Security services and mechanisms

• c) Encryption algorithms only

• d) Data transmission methods

Which type of cipher replaces one character with another?

• a) Transposition cipher

• b) Substitution cipher

• c) Stream cipher

• d) Block cipher

In classical encryption, the Caesar Cipher shifts characters by how many places by default?

• a) 2
  

• b) 3
  

• c) 4
  

• d) 5

What is the primary principle of confusion in encryption?

• a) Ensuring that ciphertext and plaintext have no correlation
  

• b) Rearranging plaintext to create ciphertext
  

• c) Splitting data into blocks
  

• d) Hiding the encryption algorithm

Which technique involves rearranging plaintext characters to form ciphertext?

• a) Substitution

• 
  b) Transposition
  

• c) Permutation

• d) Key Scheduling

The Data Encryption Standard (DES) uses a Sub key size of how many bits?

• a) 56
  

• b) 64
  

• c) 128
  

• d) 192

DES operates on data in blocks of how many bits?

• a) 32
  

• b) 64
  

• c) 128
  

• d) 256

What is the block size of AES (Advanced Encryption Standard)?

• a) 64 bits
  

• b) 128 bits
  

• c) 192 bits
  

• d) 256 bits

Triple DES applies DES encryption how many times to the data?

• a) Once
  

• b) Twice
  

• c) Thrice
  

• d) Four times