We have one big issue left to resolve,
which is how do we pick e and d to make this property true?
For correctness what we need to know is that ed - 1 is equal to φ(n),
and we know since n is the product of the primes p and q
that this is equal to (p-1)(q-1).
The quiz is which one of these should be selected randomly--
either e, d, or it doesn't matter which one?
