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Add BOLT 12 payer proof support - #845

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vincenzopalazzo wants to merge 6 commits into
lightningdevkit:mainfrom
vincenzopalazzo:macros/bolt12-pop
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Add BOLT 12 payer proof support#845
vincenzopalazzo wants to merge 6 commits into
lightningdevkit:mainfrom
vincenzopalazzo:macros/bolt12-pop

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@vincenzopalazzo

@vincenzopalazzo vincenzopalazzo commented Mar 25, 2026

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Summary

Adds support for building BOLT 12 payer proofs for previously succeeded outbound BOLT 12 payments:

  • Persist the paid BOLT 12 invoice on PaymentKind::Bolt12Offer / PaymentKind::Bolt12Refund, set from Event::PaymentSent once the payment succeeds.
  • Expose Bolt12Payment::create_payer_proof, which builds a payer proof from the persisted invoice and payment preimage. PayerProofOptions controls which optional invoice fields (offer description, issuer, amount, creation time, extra TLV types) are selectively disclosed, plus an optional proof note.
  • Wire the new PayerProof type and error variants (PayerProofCreationFailed, PayerProofUnavailable, InvalidPayerProof) through the UniFFI surface.

Since the proof is built purely from data persisted in the payment store, payer proofs survive restarts without any additional storage: no new KV namespace and no in-memory side store. Payments that completed via a static invoice (async payments) do not support payer proofs and are rejected with PayerProofUnavailable.

This PR is based on (and currently includes the commits of) #948, since it builds on the payment-id tracking prefactors. Only the last two commits are new here. The payer proof primitives landed in the rust-lightning revision pinned by #948, so this PR no longer patches LDK to a fork — Cargo.toml is untouched.

Verification

  • cargo fmt --all -- --check
  • cargo check --lib --tests --benches, cargo check --lib --features uniffi
  • cargo clippy --lib -- -A warnings -D clippy::unwrap_used -A clippy::tabs_in_doc_comments
  • cargo test --lib, cargo test --test upgrade_downgrade_tests
  • cargo test --test integration_tests_rust simple_bolt12_send_receive — extended to build a payer proof from the persisted payment and assert the payment hash, disclosed amount, proof note, and that undisclosed fields stay absent
  • Python UniFFI bindings generation (scripts/uniffi_bindgen_generate_python.sh)

Disclosure

This PR was prepared with AI assistance (Claude Code).

🤖 Generated with Claude Code

@ldk-reviews-bot

ldk-reviews-bot commented Mar 25, 2026

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👋 Thanks for assigning @tnull as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

@vincenzopalazzo
vincenzopalazzo marked this pull request as draft March 25, 2026 17:13
@vincenzopalazzo vincenzopalazzo changed the title Add BOLT12 payer proof support WIP: Add BOLT12 payer proof support Mar 25, 2026
@vincenzopalazzo
vincenzopalazzo force-pushed the macros/bolt12-pop branch 2 times, most recently from 18e0c72 to 312b662 Compare March 26, 2026 15:42
@tnull
tnull self-requested a review March 26, 2026 17:28
@vincenzopalazzo
vincenzopalazzo force-pushed the macros/bolt12-pop branch 4 times, most recently from 781d3ee to 0aaab83 Compare March 26, 2026 18:46
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🔔 1st Reminder

Hey @tnull! This PR has been waiting for your review.
Please take a look when you have a chance. If you're unable to review, please let us know so we can find another reviewer.

@ldk-reviews-bot

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🔔 2nd Reminder

Hey @tnull! This PR has been waiting for your review.
Please take a look when you have a chance. If you're unable to review, please let us know so we can find another reviewer.

Comment thread src/payment/store.rs
(3, quantity, option),
(4, secret, option),
(6, offer_id, required),
(8, bolt12_invoice, option),

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As mentioned elsewhere, we probably don't want to do this, at least not before we can use #811

Comment thread src/lib.rs Outdated
scorer: Arc<Mutex<Scorer>>,
peer_store: Arc<PeerStore<Arc<Logger>>>,
payment_store: Arc<PaymentStore>,
payer_proof_context_store: Arc<PayerProofContextStore>,

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No, I'd rather not add yet another store just for this. Can we store this in the payment metadata store post #811?

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yes OFC, I wanted to have a runnable version in a fork, but currently I am interesting in you giving some feedback on the payer proof API, if you think are good enough!

Thanks after ldk 0.3 I can wait for #811 and vibe code another integration :)

tnull added 4 commits August 6, 2026 15:15
The switch to tracking payments by ID happened with LDK Node v0.3.0,
which is >1.5 years old by now. We can be pretty certain that nobody is
upgrading from an older version to the upcoming v0.8.

Here we hence make the `payment_id` fields in `Event` required which is
a nice API simplification that will also be utilized in the next commit.

Co-Authored-By: HAL 9000
Gate manual claiming for unknown custom-hash BOLT11 payments
behind a config flag.

Nodes that do not opt in fail these payments back without storing or
queueing user events.

Co-Authored-By: HAL 9000
Create inbound BOLT11 records from claimable and claimed events so
inbound payments can be tracked by the IDs emitted by LDK.

Generate outbound BOLT11 IDs from KeysManager entropy instead of
deriving them from the payment hash.

Co-Authored-By: HAL 9000
Cover manually claiming and failing BOLT11 for-hash invoices that
were created before upgrading, so the new ID-based APIs keep
handling legacy payment-hash IDs.

Co-Authored-By: HAL 9000
Add a `bolt12_invoice` field to `PaymentKind::Bolt12Offer` and
`PaymentKind::Bolt12Refund`, and set it from `Event::PaymentSent` when a
BOLT 12 payment succeeds.

Besides being useful on its own, this gives us everything we need to
build a payer proof for a past payment without keeping any additional
state around: the invoice is persisted alongside the payment and thus
survives restarts.

This commit was written with AI assistance.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
@vincenzopalazzo vincenzopalazzo changed the title WIP: Add BOLT12 payer proof support Add BOLT 12 payer proof support Aug 11, 2026
Expose `Bolt12Payment::create_payer_proof`, which builds a BOLT 12 payer
proof for a previously succeeded outbound BOLT 12 payment, with
`PayerProofOptions` controlling which optional invoice fields are
selectively disclosed.

The proof is built purely from data we already persist in the payment
store: the paid BOLT 12 invoice recorded on `PaymentKind::Bolt12Offer` /
`PaymentKind::Bolt12Refund` and the payment preimage. That means payer
proofs survive restarts and we don't need a second, node-lifetime-only
store to keep the invoice context around.

Payments that completed via a static invoice, i.e., async payments, don't
support payer proofs and are rejected with `PayerProofUnavailable`.

Also wires the new `PayerProof` type and the two new error variants
through the UniFFI surface.

This commit was written with AI assistance.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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3 participants