## Fast Exponentiation, revisited

12/11/2019

Quite a while ago, I presented a fast exponentiation algorithm that uses the binary decomposition of the exponent $n$ to perform $O(\log_2 n)$ products to compute $x^n$.

While discussing this algorithm in class, a student asked a very interesting question: what’s special about base 2? Couldn’t we use another base? Well, yes, yes we can.

## rdrand

04/11/2019

Last week (at the time of writing, anyway), Ars Technica reported a serious bug in AMD’s implementation of rdrand, an instruction that helps you generate random numbers. Apparently, on (some) Ryzen 3000, 0xfff…ff is “random”.

I recently got an AMD Ryzen 9 3900x, and I wondered if I have the bug as well.