Symetric Cipher

Objective:

Present an overview of the main concepts of symmetric cryptography.
Explain the difference between cryptanalysis and brute-force attack.
Summarize the functionality of DES.
Present an overview of AES.
Explain the concepts of randomness and unpredictability with respect to random numbers.
Understand the differences among true random number generators, pseudorandom number generators, and pseudorandom functions.
Present an overview of stream ciphers and RC4.
Compare and contrast ECB, CBC, CFB, and counter modes of operation.

Assignment
2.1 What are the essential ingredients of a symmetric cipher?
2.2 What are the two basic functions used in encryption algorithms?
2.3 How many keys are required for two people to communicate via a symmetric cipher?
2.4 What is the difference between a block cipher and a stream cipher?
2.5 What are the two general approaches to attacking a cipher?
2.6 Why do some block cipher modes of operation only use encryption while others use both encryption and decryption?
2.7 What is triple encryption?
2.8 Why is the middle portion of 3DES a decryption rather than an encryption?
Complete your answers on a WORD Document.