4 ms·
Ah ok, so the dot operation is associative I guess? --- I mean, once you have the keys, how do you actually use them to transform data?
by alecbenzer 6y ago
Ah ok, so the dot operation is associative I guess?
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I mean, once you have the keys, how do you actually use them to transform data?
- john_alan 6y agoWith elliptic curve crypto you don’t encrypt directly with the private key (just a number) or the public key (just an x,y point). Instead we usually multiply our private key by someone else’s public key to get a point. We take that points x value, hash it and use the output as a symmetric key. The other person can take our public key and multiply it by their private key to get the same point. We end up with something like this: OurPrivate * TheirPub == secret point. (TheirPub is actually equal to TheirPrivateG, thus the secret point is really OurPrivateTheirPrivate*G)
- alecbenzer 6y agoOh, I see, we're just doing Diffie-Hellman but with elliptic curves? Ok, that makes much more sense... it was confusing for the article to compare it with RSA instead of vanilla Diffie-Hellman.
- john_alan 6y agoYup exactly that! “Encryption” with elliptic curves is just ECDH and then using a symmetric cipher like AES. Signature is a little more complicated. It’s not just “encrypting a hash”