add 126 (2020-12-02)

[adamjonas]

No description provided.

[harding]

I think this is a bit confusing. The improper preimage revelation problem was already addressed by not revealing local preimages for passthrough payments, which is what the devs thought LND was doing in the first place. This change would've also prevented the problem by a forbidding the node to release the preimage to anyone who didn't have the payment secret, which is contained in a field that's not available for passthrough payments.

Additionally, I'd prefer (but it's your choice) that we use the name from BOLT4 of "payment secret" rather than LND's pet name of "payment addr(ess)". I personally find the name "payment address" confusing and I think it has the same problem "Bitcoin address" has, which is that "address" implies it should be reused (like a mailing address), which is even less true of LN payment secrets than it is of Bitcoin output scripts/witness programs.

[adamjonas]

Simplified it and used the preferred BOLT4 naming. Hopefully, it is now more clear.