$($RSA encryption$)$ Let n $=517=85$ be the modulus of a $($very modest$)$ RSA public key encryption

and d $=3$ the decryption key. Since $85$ is between $25$ and $2525,$ we can only encode one letter $($with a

two$-$digit representation$)$ at a time. Please show all work.

a$)(10$ pts$)$ Use the decryption function

$==385$

to decipher the five$-$letter encrypted message $6844005259.$

b$)(10$ pts$)$ What is the encryption key? Use that to write the encryption function.