Zappable offer codes and per-name Lightning offers

CLINK offers (noffer): every wallet gets a static offer keypair (synced
across devices, first-minted wins) answering kind-21001 invoice
requests — from open tabs and from the service worker while closed,
which mints against the mirrored state (the record now carries chain-4
and chain-5 key windows) and raises an open-to-receive notification.
Zap requests ride along and their kind-9735 receipts publish once the
payment is claimed. The code is shown in the payment-address card for
pasting into a Nostr profile; the notifier watches and relays kind
21001 alongside NWC.

Payment names also gain a Lightning offer: the registrar creates a
BOLT 12 offer per name on the node and appends lno= to the DNS record;
a settle-forwarder pushes each received payment on to the name's ark
destination from a small float wallet (custody window: seconds between
Lightning settle and the ark send).

Name resolution now runs full client-side DNSSEC validation
(src/dnssec.js): binary DoH, root-anchor chain walk, RSA + ECDSA via
WebCrypto — the resolver is untrusted transport, verified against live
signed zones including the canonical BIP-353 test name.

Co-Authored-By: Claude Fable 5 <[email protected]>

1 files changed, 17 insertions, 44 deletions

diff --git a/src/bip353.js b/src/bip353.js
index 2bacb65..efa1721 100644
--- a/src/bip353.js
+++ b/src/bip353.js
@@ -1,55 +1,28 @@
-// BIP-353 DNS payment instructions — resolving ₿name@domain to a BIP-21 URI.
+// BIP-353 DNS payment instructions — resolving name@domain to a BIP-21 URI.
 //
 // The record lives at <name>.user._bitcoin-payment.<domain> as a DNSSEC-signed
-// TXT containing one `bitcoin:` URI. Browsers can't do raw DNS, so we resolve
-// over DNS-over-HTTPS. TRUST LEVEL, stated honestly: full client-side DNSSEC
-// validation (what the BIP ultimately wants) is not implemented yet — instead
-// we require agreement between TWO independent validating resolvers
-// (Cloudflare and Google), each reporting the answer DNSSEC-authenticated
-// (AD flag). Collusion or simultaneous compromise of both is the residual
-// risk; a native chain validator is the follow-up.
+// TXT containing one `bitcoin:` URI. Resolution runs full client-side DNSSEC
+// chain validation (src/dnssec.js): the DoH resolver is untrusted transport,
+// and every answer we act on is provably signed from the ICANN root down.
 
-const RESOLVERS = [
-  'https://cloudflare-dns.com/dns-query',
-  'https://dns.google/resolve',
-];
-
-// "a" "b" quoted character-strings → concatenated payload
-function txtPayload(data) {
-  const parts = [...String(data).matchAll(/"((?:[^"\\]|\\.)*)"/g)].map((m) => m[1].replace(/\\(.)/g, '$1'));
-  return parts.length ? parts.join('') : String(data);
-}
-
-async function queryOne(base, label) {
-  const r = await fetch(`${base}?name=${label}&type=TXT`, { headers: { accept: 'application/dns-json' } });
-  if (!r.ok) throw new Error(`resolver ${r.status}`);
-  const j = await r.json();
-  const uris = (j.Answer || [])
-    .filter((a) => a.type === 16)
-    .map((a) => txtPayload(a.data))
-    .filter((t) => /^bitcoin:/i.test(t));
-  // BIP-353: multiple bitcoin: TXT records at one label are invalid
-  if (uris.length > 1) throw new Error('multiple payment records');
-  return { uri: uris[0] || null, ad: !!j.AD };
-}
+import { resolveTxtValidated } from './dnssec.js';
 
 // name like "adam", domain like "halwallet.app" → the bitcoin: URI, or null
-// when no record exists. Throws when resolution can't be trusted.
+// when no record exists. Throws when the answer can't be proven authentic.
 export async function resolveBip353(name, domain) {
   const label = `${name}.user._bitcoin-payment.${domain}`;
-  const results = await Promise.allSettled(RESOLVERS.map((r) => queryOne(r, label)));
-  const ok = results.filter((r) => r.status === 'fulfilled').map((r) => r.value);
-  if (ok.length < 2) {
-    // one resolver down: accept a single authenticated answer, refuse a
-    // single unauthenticated one
-    if (ok.length === 1 && ok[0].uri && ok[0].ad) return ok[0].uri;
-    if (ok.length === 1 && !ok[0].uri) return null;
-    throw new Error('could not resolve the name');
+  let res;
+  try {
+    res = await resolveTxtValidated(label);
+  } catch (e) {
+    if (/^no TXT record/.test(e.message)) return null;
+    throw e;
   }
-  if (ok[0].uri !== ok[1].uri) throw new Error('resolvers disagree — refusing');
-  if (!ok[0].uri) return null;
-  if (!ok[0].ad || !ok[1].ad) throw new Error('name is not DNSSEC-signed');
-  return ok[0].uri;
+  const uris = res.txts.filter((t) => /^bitcoin:/i.test(t));
+  if (!uris.length) return null;
+  // BIP-353: multiple bitcoin: TXT records at one label are invalid
+  if (uris.length > 1) throw new Error('multiple payment records — invalid');
+  return uris[0];
 }
 
 // A pasted payment name: optional ₿, user@domain with a real-looking TLD.