Identity and contacts

An identity in DMP is two keypairs:

  • An X25519 keypair for ECDH-based encryption.
  • An Ed25519 signing keypair used to sign slot manifests, identity records, and one-time prekeys.

Both are deterministically derived from the passphrase via Argon2id plus a per-identity 32-byte random salt stored in the CLI config.

Publishing your identity 

dnsmesh identity publish

This writes a signed IdentityRecord (108 signed bytes plus a 64-byte Ed25519 signature) to DNS. The exact name depends on whether you configured a zone you control:

Shared mesh domain (TOFU)

Without --identity-domain at dnsmesh init, the record goes to id-{sha256(username)[:16]}.<mesh_domain>. Anyone can publish at any username — the hash is only a name-to-label mapping, not a trust root. Squatting is possible and mitigated only at fetch time by the --accept-fingerprint dance.

Initialize with a DNS zone you control:

dnsmesh init alice --identity-domain alice.example.com \
               --domain mesh.local --endpoint ...
dnsmesh identity publish

The record now goes to dmp.alice.example.com. Squatting requires compromising DNS for alice.example.com. Addresses take the form alice@alice.example.com — the same trust model email has had for decades.

The mesh domain (--domain) is where chunks, slots, and prekey RRsets live, and it is shared across the network. The identity domain (--identity-domain) is per-user and anchors name ownership. You can use both together.

Resolving another user 

# Legacy hash-based (TOFU) resolve
dnsmesh identity fetch alice --add

# Zone-anchored resolve
dnsmesh identity fetch alice@alice.example.com --add

Fetch verifies the Ed25519 signature on the record. --add saves the resolved pubkeys as a pinned contact.

When multiple valid records coexist at the resolver target, --add is refused and fingerprints are printed on stderr:

ambiguous: 2 valid identity records at id-2bd806c97f0e00af.mesh.local
  fingerprint=a1b2c3d4e5f60718  x25519=3f...  ed25519=ab...  ts=1776721000
  fingerprint=9988776655443322  x25519=12...  ed25519=cd...  ts=1776721200
verify out-of-band and rerun with --accept-fingerprint=<16-hex>

This is a squat-resistance guardrail under the shared mesh domain. Zone-anchored records have exactly one valid publisher by definition, so the guardrail rarely fires there.

Pinned vs unpinned contacts

dnsmesh contacts list labels each contact:

alice   3f…            (pinned)
random  aa…            (UNPINNED)

Pinned means both the X25519 encryption pubkey and the Ed25519 signing pubkey are stored. On receive, only manifests signed by a pinned signer are delivered.

Unpinned means the signing key isn’t stored. If every contact is unpinned, receive falls back to trust-on-first-use and accepts any signature-valid manifest. Useful for bootstrap, dangerous once you’re actively messaging.

Always re-add contacts with --signing-key (or bootstrap via dnsmesh identity fetch <user> --add) before treating delivered messages as authenticated. The unpinned path is documented in SECURITY.md as an explicit TOFU exception.

Rotation

Rotation shipped in M5.4. Two record types live at rotate.dmp.<user>.<domain>:

  • RotationRecord — co-signed by the old and new key, asserts that the holder of the old key authorizes the new one as its successor. Routine rotations publish only this.
  • RevocationRecord — self-signed by the revoked key, declares it dead. Used for compromise scenarios where an attacker may also hold the key; rotation-aware fetchers refuse the revoked key forever.

Run a routine rotation:

dnsmesh identity rotate --experimental

Run a compromise rotation (publishes both records):

dnsmesh identity rotate --experimental --reason compromise

Contacts who pinned you with rotation_chain_enabled=True chain-walk the rotation RRset on every fetch and pick up the new key automatically. Pre-M5.4 contacts and contacts pinned without rotation-chain support need an out-of-band re-pin (dnsmesh identity fetch <user> --add).

The wire format is a draft (v=dmp1;t=rotation;) and may bump to v=dmp2;t=rotation; after the external audit (M4.2-M4.4). The --experimental flag is intentional: it gates publication so a v0.3.0+ flag-flip is needed before rotated keys ride into a stable release. See docs/protocol/rotation.md for the wire format, co-signing rationale, and walk algorithm.