Initialization Vector (IV) Attack

What is the primary purpose of an Initialization Vector (IV) in cryptographic algorithms?

• To increase the speed of encryption

• To introduce randomness and ensure that identical plaintext blocks encrypt to different ciphertexts

• To compress data before encryption

• To manage keys in the encryption process

Which cryptographic algorithms commonly use Initialization Vectors (IVs)?

• Hash functions

• Symmetric key algorithms only

• Stream ciphers and block ciphers

• Asymmetric key algorithms

What is a predictable IV attack?

• An attack where the IV is reused with different keys

• An attack where the IV is predictable or controllable by the attacker

• An attack where the IV is kept secret

• An attack where the IV is compressed

What is a replay attack in the context of IV usage?

Reusing the same IV with the same key to repeat encrypted messages

• Reusing the same IV with the same key to repeat encrypted messages

• Changing the IV frequently

• Keeping the IV secret from the attacker

• Using a different IV for each encryption operation

How can a chosen plaintext attack exploit weaknesses in IV management?

• By compressing the IV

• By using the same IV for all encryption operations

• By choosing plaintexts and observing corresponding ciphertexts to deduce the IV and key stream

• By keeping the IV secret from the attacker

What is an IV collision attack?

• Using a different IV for each encryption operation

• Using the same IV more than once with the same key, leading to identical ciphertext for identical plaintext blocks

• Using an unpredictable IV for each encryption operation

• Keeping the IV secret from the attacker

Which of the following practices helps prevent IV attacks?

• Using a predictable IV

• Reusing the same IV with the same key

• Generating a unique and unpredictable IV for each encryption operation

• Ignoring the use of IVs in cryptographic protocols

What is authenticated encryption, and how does it relate to IV attacks?

• An encryption method that increases speed but not security

• An encryption method that provides both encryption and authentication, mitigating many IV-related attacks

• A method to compress data before encryption

• A method to reuse the same IV for all encryption operations

Why is proper protocol design important in managing IVs securely?

• To ensure IVs are predictable

• To allow reuse of IVs

• To prevent IVs from being predictable, reused, or exposed unnecessarily

• To compress the IVs before encryption