Introduction

Question 1

What are the 5 main types of cryptanalysis attacks?

Answer 1

Ciphertext Only, Known Plaintext, Chosen Plaintext, Chosen Ciphertext, Chosen Text

Question 2

Which type of attack is it when the attacker can make use of knowledge that certain text will appear, such as a standardised banner?

Answer 2

Known Plaintext

Question 3

What is a probable word attack?

Answer 3

When the attacker knows the sender is talking about specific information.

Question 4

What is a chosen plaintext attack?

Answer 4

When the attacker is able to get the source system to insert a chosen message.

Question 5

Describe the Feistel Cipher Structure.

Answer 5

Divide plaintext into two halves. Process these in rounds, where one of the halves is used to modify the other.

Question 6

How can we improve the strength of the Feistel Structure?

Answer 6

Larger blocks, larger key size, more rounds, complex subkey generation, complex round function