Julia Evanshow diffie hellman key exchange works
(with as little math as possible)
Craig Stewart@b0rk have you seen the paint explainer for Diffie-Helman? That's quite a good way to get the idea across.
@pmb00cs i have! i wanted to write something a little closer to the mathematical reality
@b0rk that's fair enough, and I think you've done an excellent job of it. I just like the paint analogy because it's easy to grasp that unmixing paint is hard.
@pmb00cs one interesting way the mixing paint metaphor doesn't work (imo) is that when you're mixing paint the two colours you're mixing both have the same "type", and it's a symmetric operation (a mixed with b is the same as b mixed with a)
but in diffie hellman the operation is not symmetric at all, like the type of the function is more like f(type1, type2) => type1
I think saying that "s" and "a" are both "numbers" might be a bit of an oversimplification in that sense
@pmb00cs but I definitely have a tendency to be overly critical about the specifics of metaphors in a way that's not necessarily helpful :)
the paint thing is cool!
@b0rk I mean, there's a point where a metaphor doesn't work anymore, because it's not the truth, just a way to explain part of the truth. If you need perfect accuracy you're just explaining reality.
The paint metaphor also breaks down because there are tools for recreating paint colours accurately from pure pigments. Do that for (sxa), (sxb), and s, and you recover a and b. So it's not really suitable as a form of key exchange. But it is easy to understand on a basic level.