In this lab, you will be working with a simplified and not very secure version of one of the most popular Symmetric-key systems DES. You can find the details here: http://www.cs.uri.edu/cryptography/dessimplified.htm

Illustrate the working of DES by completing the following fields. Input message 010010000100 and the key is 010010000. Encryption Round 1 (i = 0) 1. L0= ____________________ and R0= ____________________ ; K1 = ____________________. 2. E(R0) = ____________________. 3. E(R0) K1 = ____________________ ____________________= ____________________. 4. S1(__________) = __________, S2(__________) = _________, f(R0,K1) = __________ 5. f(R0,K1) L0 = __________ __________= __________. 6. Now using the formulas Li = Ri-1 and Ri = Li-1 f (Ri-1, Ki), L1 =__________and R1 = __________. Round 2 (i = 1) 1. L1 = __________ and R1 = __________ ; K2 = __________. 2. E(R1) = __________. 3. E(R1) K1 = __________ __________= __________. 4. S1(__________) = __________; S2(__________) = __________; f(R1,K2) = __________ 5. f(R1,K2) L1 = __________ __________= __________. 6. Now using the formulas Li = Ri-1 and Ri = Li-1 f (Ri-1, Ki), L2 =_________ and R2 = __________. So encrypted message, R2 L2 = ___________________ Decryption Round 1(i = 0) 1. L0= __________ and R0= __________ ; K2 = __________. 2. E(R0) = __________. 3. E(R0) K1 = __________ __________= __________. 4. S1(__________) = __________; S2(__________) = __________; f(R0,K2) = __________ 5. f(R0,K2) L0 = __________ __________= __________. 6. Now using the formulas Li = Ri-1 and Ri = Li-1 f (Ri-1, Kn-i), L1 = _________and R1 = _________. Round 2 (i = 1) 1. L1 = __________and R1 = __________; K1 = __________. 2. E(R1) = __________. 3. E(R1) K1 = __________ __________= __________. 4. S1(__________) = __________; S2(__________) = __________; f(R1,K1) = __________ 5. f(R1,K1) L1 = __________ __________= __________. 6. Using the formulas Li = Ri-1 and Ri = Li-1 f (Ri-1, Kn-i), L2 = __________and R2 = __________. So decrypted message, R2 L2 =________________ , which SHOULD BE SAME as the original plaintext message.