Good morning Joao, C-lightning already does this. If it is given an invoice for a payment hash it already knows, it silently succeeds and returns the preimage without sending out any money.
This should extend to any wallets built on top of C-lightning. I am uncertain what the other implementations do. Regards, ZmnSCPxj Sent with ProtonMail Secure Email. ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ On Wednesday, February 13, 2019 7:53 PM, Joao Joyce <joao.jo...@netcabo.pt> wrote: > Hi, > > Recently I've asked about the possibility of user identification across > multiple payments which now I get that it is a bad idea. > > In that previous exchange ZmnSCPxj suggested that for purposes of proving > payments (for instance for a user to redownload an already bought document) > the service could just ask for the preimage of an invoice that was already > paid. > > I was wondering if there's interest in standardising a way for payment > invoices to contain information to signal wallets that they can skip the > payment process if they are able to provide the service with a preimage for a > previous payment for that particular item. > > Use cases could extend beyond simple download of an item. For instance paying > for 30 days of a service and every time you want to access that service you > just scan the LN invoice. > > I'm aware that intermediate nodes know about this preimage but I'd rather not > focus on that for now. > > Thank you, > João Joyce _______________________________________________ Lightning-dev mailing list Lightningemail@example.com https://lists.linuxfoundation.org/mailman/listinfo/lightning-dev