[AceJohnny2]

This sends me back.

My first-year college project, a few decades ago, was to implement 4096-bit RSA encryption, the idea of my project-mate and friend (and later valedectorian) who implemented the core math.

I recall how slow prime number generation was in our final implementation, taking ~20 minutes to generate on PA-RISC workstations. My friend, a math nerd, took it upon themselves to continue optimizing the code long after the project was over. I remember them reading papers on prime number detection, and bignum math implementations. For example, one huge improvement came when the code would detect if a number in a component multiplication was 0, then skip the multiplication and give a 0 result!

[kevin_thibedeau]

On slow hardware you're much better off generating elliptic curve keys. Otherwise you wait a long time or compromise on future proof security.