a.Simplified DES On paper, decrypt the string (10100010) with key (0111111101). Show all intermediate steps by writing down the output of each function operation (IP, E/P, E/P XOR SK, S0, S1, P4, F, F XOR L, fk, SW, IP-1). Hint: As a midway check, after the application of SW, the string should be (00010011). B. Once decoded, take the first 4 bits of decoded plaintext string and apply the following scheme to find the matching alphabet letter. Do the same for the second 4 bits. A = 0000 B = 0001 O = 1110 P = 1111

I have already got the A. question answered

I still need part B answered.

So when you say you don't have enough info I don't understand

here is answer to part A. as was given via Chegg

Solution. S-DES Key Generation 10-bit key : 0111111101 Action Input Output P10 0111111101 1111110011 LS-1 11111 10011 11111 00111 P8 1111100111 01011111 (K1) LS-2 11111 00111 11111 11100 P8 1111111100 11111100 (K2) S-DES Encryption 8-bit plaintext : 10100010 (KC) IP 10100010 00110001 E/P 0001 10000010 Excusive-OR 10000010, K1 11011101 S0 1101 11 S1 1101 00 P4 1100 1001 Excusive-OR 1001, 0011 1010 SW 10100001 00011010 E/P 1010 01010101 Excusive-OR 01010101, K2 10101001 S0 1010 10 S1 1001 10 P4 1010 0011 Excusive-OR 0001,0011 0010 IP -1 00101010 00111000 8-bit ciphertext : 00111000 S-DES Decryption 8-bit ciphertext : 00111000 (DH) IP 00111000 00101010 E/P 1010 01010101 Excusive-OR 01010101, K2 10101001 S0 1010 10 S1 1001 10 P4 1010 0011 Excusive-OR 0010,0011 0001 SW 00011010 10100001 E/P 0001 10000010 Excusive-OR 10000010, K1 11011101 S0 1101 11 S1 1101 00 P4 1100 1001 Excusive-OR 1010,1001 0011 IP -1 00110001 10100010 8-bit plaintext : 10100010