Question $2$: Vigenere Cipher

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 $26.$ Forexample, if the key is $3195$ dots, then the first letter of plaintext is encrypted with a

shift of $3$ letters, the second with a shift of $19$ letters, and so on$.$

$($a$)$ Encrypt the plaintext "cryptography" with the key stream $911152816$

$1211618137.(12$ points$)$

$($b$)$ Using the ciphertext produced in part a$,$ find a key so that the ciphertext

decrypts to plaintext "kenturkeyuniv". Please explain how you did. $(13$

points$)$