Usage of pow()

[calve]

Hello,

I did a quick review inside the code, and found the following
exponentiation = (long(x)**i) % prime
at https://github.com/onenameio/secret-sharing/blob/master/secretsharing/polynomials.py#L52

I wonder if there is any reason not to use Python's built-in pow(x,y,z) which is, according to the documentation

compute more efficiently than pow(x, y) % z

I thought about timing-attack on pow() but cannot find anything on the internet

[shea256]

Hi @calve thank you for submitting this.

I'm still unclear on why this other function is better. Can you explain further?

[calve]

Hi, I would say the pow() function is better because it is in stdlib :)

As far as I know, there is no such thing as a cryptographically secure modular exponentiation, so I do not see any reason not to use the builtin.