This problem explores the use of a one-time pad version of the
Vigenere cipher. In this scheme, the key is a stream of random
numbers between 0 and 26. For example, if the key is 3 19 5…,
then the first letter of the 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 plain text “sendmoremoney” with the key stream 9
0 1 7 23 15 21 14 11 11 2 8 9
B. Using the ciphertext produced in part (a), find a key so that the
cipher text decrypts to the plain text “cashnotneeded”.