I used bip39 for the first part, but that was just to confirm I had my bearings and was using the library correctly.
The thing I actually need is to be able to go from an xpub to a public key for a specific path.
Discussion
Wouldn’t that be what the slip44 is for?
The slip has the registered coin types and I'm using Bitcoin from that list. BIP32 has the key derivation algorithm and I need that to match before it really makes sense to add on additional rounds of KDFs.
But it’s that how you deviate the path back to the master seed? Or am I just completely wrong.
The key derivation is defined here: https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki#user-content-Public_parent_key_rarr_public_child_key
BIP44 is about how many times that derivation is applied. So, BIP32 can stand on its own, but BIP44 can not. It requires the KDF from BIP32.
Also, you never deviate back to the master key, you can only go forward. It's an important detail, because if that ever were to change, all these privacy improvements would be lost, and also coins at risk in some very rare circumstamces.
Yeah I’ve been reading this for the last few days…trying to understand it.
I really appreciate you explanation here it makes a lot of sense.
Thank you.
I will try reading lots more….