
Diffie-Hellman key exchange, explained using colors - Tomte
https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange#Description
======
mdesq
I found this video helped explain the key exchange using colors quite well:
[https://www.youtube.com/watch?v=3QnD2c4Xovk](https://www.youtube.com/watch?v=3QnD2c4Xovk)

~~~
joeyspn
I was going to post this... This video gives the best explanation of DH you
can find

------
mschuster91
If I read this correctly, then a DH key exchange could be vulnerable to an
active MITM attack manipulating the initial common color?

~~~
infogulch
_All_ key exchanges are vulnerable to an active MITM attack, whether using
pigments or some cryptographic key exchange.

The only way around it? Some other method of verifying the key, which isn't
vulnerable to a MITM, like meeting in person, or using Certificate
Authorities.

~~~
rosser
Hence key-signing parties. People are still doing those, aren't they?

~~~
stcredzero
Someone needs to write fiction about bringing rufies to a key signing party.

~~~
privong
xkcd 364 is close: [https://xkcd.com/364/](https://xkcd.com/364/)

------
cliveowen
I wonder if there's a similar way to show how you would encrypt and then
decrypt a message using ElGamal, which is the natural evolution of Diffie-
Hellman.

~~~
fryguy
ElGamal requires an inverse element, which isn't possible with colors to my
knowledge.

------
agwa
Wikipedia has this in English:

[https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exc...](https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange#Description)

~~~
dang
Thanks. I think we'll change the url to this from [1].

Hacker News is an English-language site. Obviously, content in other languages
is often just as good or better. But it is what this site is. Machine
translation is surprisingly not bad these days, but I don't think it's a
general solution here.

1\. [http://blog.zeit.de/mathe/allgemein/daten-
verschluesselung-m...](http://blog.zeit.de/mathe/allgemein/daten-
verschluesselung-mathe/)

~~~
Tomte
Sure.

I hadn't come across this kind of explanation and didn't think of checking
Wikipedia.

I thought it was an original idea by the author.

------
doctorKrieger
guys I hope you are aware that's like high-school math?

------
jessaustin
Gee thanks for showing me that different areas of my crappy monitor display
color differently.

