Derive K1, the first-round subkey. b. Derive L0, R0. c. Expand R0 to get E[R0], where E[ # ] is the expansion function of Table S.1. d. Calculate A = E[R0] ⊕ K1. e. Group the 48-bit result of (d) into sets of 6 bits and evaluate the corresponding S-box substitutions. f. Concatenate the results of (e) to get a 32-bit result, B. g. Apply the permutation to get P(B). h. Calculate R1 = P(B) ⊕ L0.
Question no 2
15
Perform encryption using a one-round version of DES. Start with the same bit pattern for the key K
and the plaintext, namely:
Hexadecimal notation: 0 1 2 3 4 5 6 7 8 9 A B C D E F
Binary notation: 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101
1110 1111
a. Derive K1, the first-round subkey.
b. Derive L0, R0.
c. Expand R0 to get E[R0], where E[ # ] is the expansion function of Table S.1.
d. Calculate A = E[R0] ⊕ K1.
e. Group the 48-bit result of (d) into sets of 6 bits and evaluate the corresponding S-box
substitutions.
f. Concatenate the results of (e) to get a 32-bit result, B.
g. Apply the permutation to get P(B).
h. Calculate R1 = P(B) ⊕ L0.
i. Write down the ciphertext
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