Write the following computer programs to simulate a mini data encryption system (MDES). Since it is just a simulation, the bit and the binary strings in the following can be expressed as integers 0 and 1. 2. Write a program to implement a function f as follows. The inputs of the function are a bitstring B (plaintext) of length & and a round key K which is a bitstring of length 12. First, B is expanded into 12 bits according to the following: 1 2 3 4 3 4 5 6 5 6 7 8 For example, 10110101 is expanded to 101111010101.) Then the expanded string is XORed with the round key K. The resulting 12-bit is split into two parts B1 and B such that each part has 6 bits. Finally, Bi passes through S-box S1 and B2 passes through S, (using a method similar to that in DES). The output off is a 8-bit string obtained from the output of two S-boxes. The S-boxes are as follows. 15 1 8 14 6 11 4 9 7 2 13 12 O 5 10 3 13 4 7 15 2 8 14 12 0 1 10 6 9 11 S. 5 0 14 7 11 10 4 13 1 5 8 12 6 93 2 15 13 8 10 1 3 15 4 2 11 6 7 12 0 5 14 9 and S2 7 13 14 3 0 6 9 10 13 8 11 5 6 15 0 3 10 6 90 12 11 7 13 3 15 0 6 10 1 13 8 1 2 8 5 11 4 7 2 12 1 15 1 3 14 5 11 12 12 4 15 10 14 9 2 8 4 7 2 14 Write the following computer programs to simulate a mini data encryption system (MDES). Since it is just a simulation, the bit and the binary strings in the following can be expressed as integers 0 and 1. 2. Write a program to implement a function f as follows. The inputs of the function are a bitstring B (plaintext) of length & and a round key K which is a bitstring of length 12. First, B is expanded into 12 bits according to the following: 1 2 3 4 3 4 5 6 5 6 7 8 For example, 10110101 is expanded to 101111010101.) Then the expanded string is XORed with the round key K. The resulting 12-bit is split into two parts B1 and B such that each part has 6 bits. Finally, Bi passes through S-box S1 and B2 passes through S, (using a method similar to that in DES). The output off is a 8-bit string obtained from the output of two S-boxes. The S-boxes are as follows. 15 1 8 14 6 11 4 9 7 2 13 12 O 5 10 3 13 4 7 15 2 8 14 12 0 1 10 6 9 11 S. 5 0 14 7 11 10 4 13 1 5 8 12 6 93 2 15 13 8 10 1 3 15 4 2 11 6 7 12 0 5 14 9 and S2 7 13 14 3 0 6 9 10 13 8 11 5 6 15 0 3 10 6 90 12 11 7 13 3 15 0 6 10 1 13 8 1 2 8 5 11 4 7 2 12 1 15 1 3 14 5 11 12 12 4 15 10 14 9 2 8 4 7 2 14