3.11 This problem provides a numerical example of encryption using a one-round version of DES. We 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. | |
| View Solution | |
| << Back | Next >> |