Question 8 (35 points). This question asks you to go through one round of DES encryption standard. Suppose the plaintext and the key are the same (in HEX format): 0x0123456789ABCDEF (1) Derive K1, the first round subkey Solution: Key: 0x0123456789ABCDEF key (binary) 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 DO: 1010 1010 1100 1100 1111 000000 C1: 1110 0001 1001 1001 0101 0100 0001 D1: 0101 0101 1001 1001 1110 0000 0001 K1: 0000 1011 0000 0010 0110 0111 1001 1011 0100 1001 1010 0101 (2) Derive LO, RO. (3) Expand RO to get E[RO], where EL.] is the expansion function as shown in page 18 of the slide about DES. (4) Calculate A-E[R0] XOR K1. (5) Group the 48-bit result of d into sets of 6 bits and evaluate the corresponding S- box substitutions (6) Concatenate the results of (e) to get a 32-bit result, B. (7) Apply the permutation to get p(B). (8) Calculate R1-P(B) XOR LO Question 8 (35 points). This question asks you to go through one round of DES encryption standard. Suppose the plaintext and the key are the same (in HEX format): 0x0123456789ABCDEF (1) Derive K1, the first round subkey Solution: Key: 0x0123456789ABCDEF key (binary) 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 DO: 1010 1010 1100 1100 1111 000000 C1: 1110 0001 1001 1001 0101 0100 0001 D1: 0101 0101 1001 1001 1110 0000 0001 K1: 0000 1011 0000 0010 0110 0111 1001 1011 0100 1001 1010 0101 (2) Derive LO, RO. (3) Expand RO to get E[RO], where EL.] is the expansion function as shown in page 18 of the slide about DES. (4) Calculate A-E[R0] XOR K1. (5) Group the 48-bit result of d into sets of 6 bits and evaluate the corresponding S- box substitutions (6) Concatenate the results of (e) to get a 32-bit result, B. (7) Apply the permutation to get p(B). (8) Calculate R1-P(B) XOR LO