Migrating from LND while preserving seed

[kiwiidb]

Would it be possible to migrate from an LND node and keep the same public key? I'm not talking about channels or even recovering on-chain funds - just the same node id. Is it possible to go from LND's 24 words to a node_seed.dat usable by Eclair?

[t-bast]

That's a good question, I know that lnd has been using their own derivation for keys, so I'm not sure this is possible. Eclair's node_seed.dat is just random bytes used to create a standard BIP32 xpriv, but if lnd doesn't use BIP32 derivation, that won't yield the same nodeId...

[kiwiidb]

What about this: https://github.com/guggero/chantools#seed-and-passphrase-input

[t-bast]

I have no idea, I don't know anything about lnd's internal key derivation.
But you can probably test this and see if you're able to come up with the same nodeId?
Eclair's node_seed.dat and channel_seed.dat are just binary files that contain the seed bytes.

[kiwiidb]

Will test & report back.

[kiwiidb]

I've been testing out a few things.

• Use chantools to dump LND's cipherSeed.Entropy. Notice that the seed is only 16 bytes instead of 32, but I am not sure if that actually matters here.
• Figure out the default derivation paths used by LND / Eclair. For LND (regtest) I think that the derivation path is something like m/1017'/1'/6'/0 (purpose/ account)
• So I've been trying to very crudely change what I think is Eclair's derivation path for the node key to match LND's. Then I copy over the 16-byte node_seed.dat that I dumped from the cipherSeed mentioned above and start Eclair.
  Alas, no luck, the pubkey is still not the same :/

[t-bast]

Notice that the seed is only 16 bytes instead of 32, but I am not sure if that actually matters here.

This shouldn't matter, we simply feed this seed into a standard BIP 32 HD wallet, so as long as lnd does the same, it should work with only 16 bytes.

I've been trying to very crudely change what I think is Eclair's derivation path for the node key

The one you should change is here: https://github.com/ACINQ/eclair/blob/master/eclair-core/src/main/scala/fr/acinq/eclair/crypto/keymanager/LocalNodeKeyManager.scala

The one you changed is for channel keys (keys used for channel transactions).

Eclair explicitly separates the node_seed (keys used for encryption tcp connections and responsible for your node_id) from channel_seed (keys used for on-chain transactions). These two types of keys don't have the same liveness requirements, that's why we separated them.

Hopefully that will make it work?