Advanced Encryption Standard in Cryptography- Session 4

  
    Exercise 1
    Let’s consider the following operation performed during the mix columns step in Advanced Encryption Standard 
    
    
    Compute the result of the following operation using finite field arithmetic GF(28) from the matrices given above. Use X8+X44+X3+X+1 as the irreducible polynomial for the computation. Show all the steps in the solution.
    
           03*63 +02*9C +   01* 7b + 01 * ca =?
    
    
    Exercise 2
    Let’s consider the following operation performed during the mix columns step in Advanced Encryption Standard 
    
    
    Compute the result of the following operation using finite field arithmetic GF(28) from the matrices given above. Use X8+X44+X3+X+1 as the irreducible polynomial for the computation. Show all the steps in the solution.
    
    01*47 +03*63 +   02* 7c + 01 * af =?
    
    
    Exercise 3
    Let’s consider the following operation performed during the mix columns step in Advanced Encryption Standard 
    
    
    Compute the result of the following operation using finite field arithmetic GF(28) from the matrices given above. Use X8+X44+X3+X+1 as the irreducible polynomial for the computation. Show all the steps in the solution.
    
    03*a2 +02*c5 + 01* f0 + 01 * 76 =?
    
    Exercise 4
    Elaborate the steps involved in the computation of the following 
    i.	Generation of 10 sub keys using the 128 bit input key in Advanced Encryption Standard.
    ii.	Computing the output of a Round during Encryption in Advanced Encryption Standard