transactions – Calculation of various Pubkeys in Lightning based on BOLT03

Lightning makes use of totally different Pubkeys to realize extra privateness and safety, I’m not certain how they’re calculated. In BOLT03 it says:

The corresponding non-public keys could be equally derived, if the basepoint secrets and techniques are identified (i.e. the non-public keys comparable to localpubkey, local_htlcpubkey, and local_delayedpubkey solely):

privkey = basepoint_secret + SHA256(per_commitment_point || basepoint)

I used to be questioning whether or not its the identical per_commitment_point we use for our native dedication revocation path, which secret later will get revealed to revoke the native dedication tx.

That means that the “to_local” path appears to be like as the next:

OP_IF
    # Penalty transaction
    <revocationpubkey>
OP_ELSE
    `to_self_delay`
    OP_CHECKSEQUENCEVERIFY
    OP_DROP
    <local_delayedpubkey>
OP_ENDIF
OP_CHECKSIG

the place the local_delayedpubkey is calculated like this:

local_delayedpubkey = basepoint_local_delayedpubkey + SHA256(per_commitment_point || basepoint_local_delayedpubkey) * G

and the revocationpubkey is calculated as follows:

revocationpubkey_local = revocation_basepoint_remote * SHA256(revocation_basepoint_remote || per_commitment_point) + per_commitment_point * SHA256(per_commitment_point || revocation_basepoint_remote)

With each paths utilizing the identical per_commitment_point which was created domestically or to write down it otherwise:

per_commitment_point_local

which means that when I’ve to get better from a pressure shut, I all the time must not my newest per_commitment_point_local to comb my “to_local” funds after I broadcast my pressure shut transaction