· Read all the definitions in section 2.1
§ Is it better to let the attacker know the encryption algorithm? Why or why not?
§ Think about the ways the sender and the receiver of a text can exchange their common key. Should the key be encrypted too during key exchange? Why or why not?
§ What are the essential elements of a symmetric encryption scheme?
§ What is cryptanalysis? What is Brute-force attack? Read all types of attacks from TABLE 2.1.
§ What is the difference between unconditionally secure and computationally secure?
§ Is AES better that DES from perspective of computational security? Why or why not?
· Read section 2.2. Read about all types of ciphers described here.
§ Which cipher seems to be the most secure?
§ What is the advantage of one-time pad? What’s the disadvantage?
· Sections 2.3 and 2.4: Read briefly.
· Section 2.5: Steganography
§ How is steganography different from cryptography?
§ Which technique is more secure to hide texts?
§ Read more about digital steganography from http://www.jjtc.com/Steganography/