From rusty at rustcorp.com.au  Thu Nov 14 01:59:01 2019
From: rusty at rustcorp.com.au (Rusty Russell)
Date: Thu, 14 Nov 2019 12:29:01 +1030
Subject: [Lightning-dev] [VERY ROUGH DRAFT] BOLT 12: Offers
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Message-ID: <87o8xfnrq2.fsf@rustcorp.com.au>

Yaacov Akiba Slama <ya at slamail.org> writes:
> So we can integrate between them without intermixing the semantics of
> the protocols but we need only to define the interaction points between
> them.
>
> In the previous worflow, the seller can for instance add in the LN
> invoice H(Quotation (UBL)||Order(UBL)||Prepayment Invoice(UBL)), and use
> H(Receipt(UBL)) as preimage. With such a workflow, the UBL documents are
> cryptographically tied to the LN payment.
>
> So the property of UBL of not being machine *handlable* is not altered
> but the LN cryptographic properties are still used to tie the workflow.
>
> Am I missing something?

Sure, people can do this today: simply set your `d` field to "UBL:
<hash>".

But it provide what we want from offers:
1. Does not provide a "static invoice" flow.
2. Does not provide a donation flow.
3. Does not provide a method for wallets to do recurrence.
4. Does not provide end-to-end over LN (i.e. no HTTP(s) requests).

Cheers,
Rusty.