Let n $=307\backslash$times $491.$ Use the Blum$-$Blum$-$Shub generator to generate $63$ pseudorandom bits. Use seed

x$0=1010002=40.$

a$)$ What is the sequence of keystream bits?

b$)$ Decrypt the ciphertext:

$101110001001000001000000111110100110010000000011001000111110000$

encrypted with stream cipher and key stream generated in a$).$ Each plaintext message is a

sequence of characters; each character is represented as an $7-$bit binary number using the ASCII

character encoding. What is the plaintext $($in $7-$bits ASCII character encoding$)?$