$1)$ Encode the letters A to Z as the numbers $11$ to $36,$ respectively. Set p $=541,$ q $=607$ and a $=227.$

$($a$)$ Use RSA with public key $($a$,$ pq$)$ to encrypt the message consisting of the first two letters of your surname, as recorded in the UOW database.

The two letters yield a single, $4-$digit block for encryption, not two $2-$digit blocks. For example, if the first two letters of your family name is PA$,$ then

the $4-$digit block that you need to encrypt is $2611.)$

$($b$)$ Compute the private decryption key.

$($c$)$ Decrypt the encrypted message.