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60 sats \ 3 replies \ @nerd2ninja 20 Jan 2023 \ parent \ on: emon: encrypted messaging over nostr with lightning integration ⚡ nostr
https://medium.com/asecuritysite-when-bob-met-alice/a-bluffers-guide-to-secp256k1-404e423e612
The main applications of secp256k1 are in digital signing (ECDSA) and key exchange (ECDH)
ECDH with secp256k1 can apparently be used to generate a shared key which is then used in the AES cipher. I'm continuing this rabbit hole though because my mind is getting blown to bits:
https://asecuritysite.com/ecdh
You guys gotta learn this with me. This is nuts if true. If the participants really can't find each other's private keys after this exchange.
Will learn this with you when I have more time. I am on mobile atm and switching tabs and stuff gets really annoying haha
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Nooo because in order for this to work,
"Bob will generate a public key (B) and private key (b), as will Alice (A and a). They then exchange their public keys, and the shared key will then be a×b×G, and where G is the generator point on the elliptic curve."
https://www.youtube.com/watch?v=aQ9pZ6wVV_E
Okay so Bob sends bG to Alice and Alice sends aG to bob, but then that means Alice can do result/G = b and Bob can do result/G = a and then on NOSTR start posting notes as each other's identities...right?
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No. I haven't watched your video but Computerphile made a very good video about diffie hellman: https://youtu.be/NmM9HA2MQGI
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