Seeing an example can be more helpful. Let’s say that \(p=7\) and  \(q=17\), \(n\) can be computed by \(pq\) and in our case \(pq=119\). To calculate \(\phi n\) we do \(\left(7-1\right)\left(17-1\right)\),  \(\phi n=\left(6\cdot16\right)=96\). Next, \(d\) will be chosen. Keep in mind that \(d\) must be relatively prime  to \(\phi n\). In our case lets say \(d=5\). We now can plug this onto our equation to  find the value of \(e\). In our case \(5e+96f=1\) . We can see that \(e=19\) and \(f=-1\) in order to satisfy our equation. Now in order to encrypt the message we take  our message \(M\) and raise it to the \(e\) power (mod \(n\)), in this case lets say we  want to send the message \(2\), so we can encrpty by saying \(2^{19}\) (mod \(119\)) which