$(1$ point$)$ A cryptography student has accidentally used the same keystream to encrypt two different

messages, $M_1$ and $M_2.$ We know that the ciphertexts are $C_1=0xe0a22570$bde$7a0f2$ and

$C_2=0xe6f64951a12ce91b.$ We also happen to know that $M_1=0x1$cfddae$15dc57899.$

a$)$ What is $M_2$ in hexadecimal? Please give your answer a leading $0x$ and use lowercase letters only.

b$)$ What is the keystream? Please give your answer a leading $0x$ and use lowercase letters only.

Hint: These are all $8$ byte numbers and will fit in an unsigned long type on most systems.