HOMEWORK # 3: CS 386 Due Date: February 29, 2018 b autokey system 2. This problem explores the use of a one-time pad version of the Vigenre cipher. In this scheme, the key is a stream of random numbers between 0 and 26. For example, if the key is 3 195 then the first letter of plaintext is encrypted with a shift of 3 letters, the second with a shift of 19 letters, the third with a shift of 5 letters, and so on. a Encrypt the plaintext sendmoremoncy with the key stream 9 01 7 23 15 21 14 11 11 2 8 9 h. Using the ciphertext produced in part (a), find a key so that the cipher text decrypts to the plaintext cashnotneeded. letter A EIMO R T V encoding 000 001 010 011 100 101 110 111 A message M = "MARIO is Vernam encrypted into ciphertext C = AC)AMV: C' M K where e shows modulo 2 XOR operation. Find the corresponding encryption key. Provide details of your cryptanalaysis 4. DES Illustration This problem provides a numerical example of encryption using a one-round ver- sion of DES Hexadecimal notatio: 0123456789ABCDE Binary notation 0000 0001 0010 0011 0100 0101 01100111 000 1001 1010 1011 1100 1101 1110 1111 a. Derive K, the first-round subkcy. b. Derivela. . Expand R, to get FRJ where El-l is the expansion function of Tahle S1 d. Calculate A-ERIk, e. Group the 48-bit result of (d) into sets of 6 bits and evaluate the corresponding S-box substitutioms L Concatenate the results of (c) to get a 32-bit result, B Apply the Calculate R-PMB)L lo get MB) L Write down the ciphertext The given plain text (in hexadecimal form), P = D2AAF891CEOB6587 Key, K = B01 94D2FA3487EC6 First convert both P and K in binary form using 64 bits (each hex digit by 4 digit binary number as shown). Then answer each of the question given above