Are d8, 10, 12, etc. dice, fair dice?

Given a perfectly formed d8, or d10 or any d dice in Dungeons & Dragons (D&D), are they all fair dice? Is it equally possible to roll any number on any given dice?

I am writing a text based, online D&D engine that would allow a DM to create their own world and invite their friends to play that world online. I am writing a cryptographically secure random number generator to roll the dice, but knowing nothing about D&D, I don’t know if all the dice are fair.