(b) autokey system 2. This problem explores the use of a onc-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 sendmoremoney with the key stream 90 1 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 EIMOR T V encoding 000 001 010 011 100 101 10111 A message M MARIO is Vernam encrypted into ciphertext C = AOAMV: C = M K where shows modulo 2 XOR operation. Find the corresponding encryption key. Pvde details of your cryptanalaysis. 4. DES Illustration This problem provides a numerical example of encryption using a one-round ver- sion of DES 0123456789ABCDE Hexadecimal notati Binary notation 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 11001101 1110 1111 a. Derive the first-round subkey. h. Derive la R G. Expand R, to get EIRl.where El l is the expansion function of Table S1 d. Calculate A-EIRI e. Group the 48-bit result of (d) into sets of 6 bits and evaluate the corresponding S-box substitutions. concatenate the results of (e) to Apply the Calculate R.-PiB)4 r. et a 32-bit result, B. to get PIB) L Write down the ciphertext. The given plain text (in hexadecimal form), P= D2AAF891CEOB6587 Key, K - B0194D2FA3487EC6 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