0xchat: Namecoin .bit NIP-05 resolution for DM impersonation defense

Opened a PR against 0xchat-app/0xchat-app-main adding optional Namecoin .bit verification to the existing NIP-05 path.

PR: https://github.com/0xchat-app/0xchat-app-main/pull/65

What it does

• NIP-05 addresses ending in .bit (e.g. [email protected]) are verified against the Namecoin name record over a public ElectrumX server instead of an HTTPS .well-known/nostr.json endpoint.
• Contact / profile / user-center views render a distinct Namecoin badge for chain-verified handles, so DM users can tell DNS-backed identities from chain-backed ones at a glance.

Why this one matters

0xchat is a Nostr-first DM client. The threat model that gets actually exploited on Nostr DMs is impersonation: an attacker creates a fresh npub with the same display name and picture as someone you trust and DMs the people you talk to.

DNS NIP-05 helps with that — until the DNS record gets rotated, transferred, or hijacked silently. A .bit handle resolves to a record on the Namecoin blockchain; the mapping is authoritative, transferable only via signed on-chain transactions, and rotation-proof from the user's perspective.

A distinct badge makes that distinction visible to the user without forcing them to read pubkeys.

Scope

What	Where
Resolver (ElectrumX WSS, scripthash, NAME_UPDATE/NAME_FIRSTUPDATE parse, JSON-value extractor, ifa-0001 import walk)	packages/0xchat-core/lib/src/account/namecoin/ (new, 6 files)
.bit-suffix branch in NIP-05 verify	one early-return branch in Account.getDNSPubkey
Distinct "Namecoin" badge widget	ox_common/widgets/nip05_verified_badge.dart
Three NIP-05 indicator call sites swapped to the new widget	ox_chat contact options, ox_discovery contact info, ox_usercenter page UI
Unit tests	test/namecoin/ (3 files, 28 tests)

Footprint: +1638 / −24 across 17 files. Falls back gracefully on resolver failure.

Wire format

Same wire format already implemented in:

• Kotlin/Android — vitorpamplona/amethyst (merged across PRs #1734, #1771, #1785, #1786, #1806, #1815, #1937, #2199, #1914, #1915, #2595, #2956, #2957).
• Swift/iOS — nostur-com/Nostur (PR #60).
• Dart/Flutter — ethicnology/dart-nostr (PR #44, merged 2026-05-16).
• Flutter app — haorendashu/nostrmo (PR #33, in review).
• JS/TS — nbd-wtf/nostr-tools (#533), CodyTseng/jumble (#774), hzrd149/nostrudel (#352).

Specifically:

• ElectrumX v1.4.1 blockchain.scripthash.get_history over the canonical name-index script.
• Both NAME_UPDATE (OP_3) and NAME_FIRSTUPDATE (OP_2) are decoded.
• Three nostr value shapes (simple, names/relays map, single-identity pubkey).
• ifa-0001 §"import" walked with cycle detection, capped at depth 4.
• Anti-leak: if names["alice"] is malformed, return null rather than silently falling back to the root operator's pubkey.

Try it

mstrofnone.bit and id/mstrofnone resolve to npub1gvv9ahktvavf9qjtrgm62le7gplmmchd5usp5wpfhr85hf79kncqj8xchs on the Namecoin chain. Adding either as a NIP-05 in your 0xchat profile and re-verifying should surface the new badge.

Related artefacts

• N1 NIP draft (.bit NIP-05) — mstrofnone/nips.
• N1 upstream PR — nostr-protocol/nips#2349.
• dart-nostr precedent — ethicnology/dart-nostr#44, merged 2026-05-16.

This is the seventh shipping reference implementation of Namecoin NIP-05, across five language runtimes (Kotlin, Swift, JS, Dart, plus the wire-compatible Go nak port).