bLIP: BOLT 11 Invoice Blinded Path Tagged Field

[t-bast]

@roasbeef

Since then, based on comments like this, it appears there’s a sort of gentleman’s agreement to not expose an encoding format for BOLT12 invoices. Has your thinking here evolved since May?

I’d rather not expose Bolt 12 invoices and use the full offer flow every time, but if I had to choose between adding blinded paths to Bolt 11 invoices or exposing Bolt 12 invoice, I’d rather expose Bolt 12 invoices. This requires less code and less additional spec work.

To be honest, I don’t think we should waste time with such intermediate steps (that will need to be maintained for a long time, create technical debt and confusion for users). I find it more useful to focus that time on shipping Bolt 12 code, but that’s just my opinion.

@ellemouton

users who are not aware of the new addition will get a useful error message from the parser saying “the invoice uses unknown required feature bit x” which will then give the user an idea of what has gone wrong.

I don’t think this is very useful…I don’t believe this will prompt users to ask wallet developers to implement stuff, and the only result of that is a bad UX where users scan a QR code and they’re told it doesn’t work.

@roasbeef

Ignoring any user-facing wallet uptake (implications re QR code encoding and multi-formats), there exist fully programmatic flows like the L402 protocol (or sub-swap services like Loop) that can use the BOLT 11 extensions to leverage blinded paths and all their benefits. I think blinded paths are super interesting in the context of sub-swap services as they’d allow a receiver to curate the route to them, potentially picking certain routes they know to be lower fee or more reliable.

I haven’t looked at the details in a while, but at a high-level it seems to me that L402 would benefit a lot from using offers rather than hacking blinded paths on top of Bolt 11 invoices? That requires more work to upgrade L402, but I’m a strong believer that doing short-term intermediate “hacks” is always a waste of time in the long term because of the maintenance cost.