vjrj
49b872b405
Throwaway research spike (spike/ branch, outside pub workspace, no prod deps touched). Validates the open Block 2 decisions before committing a funded round: 1. Deterministic one-way secp256k1 (Nostr) key derived from the Ğ1 root seed via HKDF — user still backs up ONE thing. Reproducible + signs (BIP340). 2. OfferTransport abstraction over Nostr NIP-99 (kind 30402); Offer stays inventory/location-agnostic, geohash coarsened on the wire (tested). 3. publish->discover-by-geohash proven end-to-end against an in-process hermetic mini-relay (~34ms round-trip). Findings + risks + recommendation in docs/design/spike-block2-findings.md. Block 1 suite untouched. 14 tests green, analyzer clean.
77 lines
2.3 KiB
Dart
77 lines
2.3 KiB
Dart
import 'dart:convert';
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import 'package:bip340/bip340.dart' as bip340;
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import 'package:crypto/crypto.dart';
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/// A minimal Nostr event (NIP-01): enough to build, id, sign and serialise
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/// NIP-99 classified listings. Throwaway — production would use a vetted client.
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class NostrEvent {
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NostrEvent({
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required this.pubkey,
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required this.createdAt,
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required this.kind,
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required this.tags,
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required this.content,
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this.id = '',
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this.sig = '',
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});
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final String pubkey; // x-only hex
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final int createdAt; // unix seconds
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final int kind;
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final List<List<String>> tags;
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final String content;
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String id;
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String sig;
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/// NIP-01 id: sha256 of the compact JSON array
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/// `[0, pubkey, created_at, kind, tags, content]`.
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String computeId() {
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final serialized = jsonEncode([0, pubkey, createdAt, kind, tags, content]);
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final digest = sha256.convert(utf8.encode(serialized));
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return digest.toString(); // lower-case hex
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}
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/// Fills [id] and [sig] (BIP340 Schnorr over the id) with [privateKeyHex].
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void signWith(String privateKeyHex, {String? auxRandHex}) {
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id = computeId();
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// Deterministic aux in the spike (derived from id) so round-trip tests are
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// reproducible; production uses fresh randomness per BIP340.
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final aux = auxRandHex ?? id;
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sig = bip340.sign(privateKeyHex, id, aux);
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}
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/// Verifies the signature against [pubkey]. Cross-checks that a real relay /
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/// peer would accept what we produced.
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bool verify() => id == computeId() && bip340.verify(pubkey, id, sig);
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Map<String, dynamic> toJson() => {
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'id': id,
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'pubkey': pubkey,
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'created_at': createdAt,
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'kind': kind,
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'tags': tags,
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'content': content,
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'sig': sig,
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};
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static NostrEvent fromJson(Map<String, dynamic> j) => NostrEvent(
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id: j['id'] as String,
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pubkey: j['pubkey'] as String,
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createdAt: j['created_at'] as int,
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kind: j['kind'] as int,
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tags: (j['tags'] as List)
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.map((t) => (t as List).map((e) => e as String).toList())
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.toList(),
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content: j['content'] as String,
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sig: j['sig'] as String,
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);
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/// First value of the first tag named [name], or null.
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String? tag(String name) {
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for (final t in tags) {
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if (t.isNotEmpty && t[0] == name && t.length > 1) return t[1];
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}
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return null;
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}
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}
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