Assume you have intercepted a ciphertext message and you know the symmetric

encryption algorithm that was used to encrypt the plaintext message. You also know

that a $64-$bit key was used, and intend to try all possible encryption keys in an

attempt to recover the plaintext.

How long would you need, on average, to find the correct key if you can decrypt at a

rate of $1$ tebikey$/$second$?$ Express your answer in terms of the number of days,

hours, minutes, and seconds that would be needed $($e$.$g$.4$ days, $7$ hours, $22$ minutes,

and $12$ seconds$).$ Show each step of your calculations and explain your process.

Apart from the issue of raw computational power, why would it likely take you longer

to find the correct encryption key in practical terms? Explain in detail.