So, for software engineers, or for people who design crypto-algorithms,

what they care is, they care about the correctness of the algorithm.

They, what they want is, they say, I want to calculate a to the power e mod n.

And it is the job of hardware designers to implement this one efficiently.

Efficiency in the terms of computation time,

how fast you can find out the results.

In terms of energy consumption, how much energy,

or how much power it's going to take to do such operation.

And for hardware designers,

we have been doing our job in terms of how to optimize design all the time.

I mean, this particular time, one question we want to ask is,

can we do multiplication less than e minus 1 times?

Because in both these two approaches you have to multiply a with some number for

e minus 1 times.