Diffi-Hellman is actual magic. You can exchange keys over an unencrypted channel and end up with guarenteed unique keys, on which you can start a secure channel

Like how??

oooh I was looking for something like this

yooink

Something to do with buckets of paint, apparently.

Not necessarily unique. But yes, DH indeed is cool!

with ca or somebody is in the middle

DH is just taking advantage of asymmetric encryption keys. The real magic is those keys in the first place...

I can literally give you a key that allows you to encrypt a message that only I can read because I know a completely different key that I never told anyone.

EDIT: I do like the ratcheting alternatives a lot though, very clever stuff as well

Funnily enough, you can even make it a shared key with multiple participants. You just have to run it in a circle. A chat with 30 people? No issue, just run it from person to person. It is amazing. Shared secret. Anyone listening? No issue.

I think that's often overlooked, but Diffie Hellman can make a key with n>=2 participants. My favorite feature!

@TrayKnots scuse me while I go google. 2 participants makes intuitive sense, need to go read about this. Interesting!

OK but like... Why not just set up 5 2 way exchanges instead? I guess to verify that everyone got the same message.

@atheist

I think they do 5 2-ways. It is easier and imagine a group chat. Easier to hand out the old key or maybe make a new key if old messages should not be shared than waiting until everyone had been online at least once with the last person online.

I just think it is neat that it is possible. And there will be probably some cool use cases. Like common key for systems that are not in real-time communication? Like a letter system? Don't forget you can always send it home early.

Like 1-2-1

And then just act like that hasn't happened and make it 1-2-3-1. And so on. Might be a cool way to solve a problem with lightspeed delay?

Until yet another idiot decides to stand up and think for a while instead of learning crap at school, writes some simple equation and push forward entre civilization by thousands of years.

It’s just temporary solution that works because of science stagnation.

no. it's just math.

we actually learned how it works in university, and even did the calculations by hand as an exercise.

the gist of it is: primes are awesome. primes are the math equivalent of "magnets"

@tosensei

Correct, it's just math. But math is magic, though.

@TrayKnots no. the other way around.

magic is just advanced technology, and technology is just applied math.

@tosensei

I am with you that magic is advanced technology. But an equal sign. Not a direction.

Also math. Fucking hell, math is magic. What you can reason from betweenness of graphs or statistical analysis of problems.

How many bears are there... Hmm.. Let's catch a bear, mark him with color, release him and then start catching bears until we catch our marked bear again. And we have a pretty good idea of how many bears there are.

I raise my child knowing that if she goes to uni and chooses natural science of any kind, she essentially goes to Hogwarts. Magic is real. Wanna be a witch? Study math and sciences!

the whole semantic point of "magic" is the implication of "you do not know how it works".

once you know how it works (by understanding maths, in this case) it ceases to be "magic"

@tosensei No, it’s still pretty magical.

@Root compromise: mathemagical?