receive-opportunistic-lxmf.md mirrors the send flow on the recipient
side: KISS/HDLC deframe -> Transport.inbound -> packet_filter dedup ->
DATA/SINGLE branch -> Destination.receive -> Identity.decrypt with the
ratchet ring + long-term-key fallback -> LXMRouter.delivery_packet (which
fires the PROOF receipt before parsing) -> LXMessage.unpack_from_bytes
with msgpack stamp-strip -> ticket/stamp/dedup checks -> __delivery_callback
to the app. Notes upstream's narrower variant tolerance vs SPEC.md §5.6
and the missing clockless-sender fix-up vs §9.6.
send-link-lxmf.md walks the DIRECT method end-to-end: process_outbound
DIRECT branch decides reuse-vs-establish, RNS.Link.__init__ builds the
unencrypted LINKREQUEST body (initiator_X25519_pub || initiator_Ed25519_pub
|| optional signalling), link_id derived from get_hashable_part, LRPROOF
arrives back and validate_proof verifies signature against the responder's
long-term Ed25519 pub recalled from a prior announce, handshake() does
ECDH+HKDF over the shared secret with salt=link_id, lxmessage.send sends
the full LXMF body (with dest_hash, per §5.2) over the link with Token
encryption that omits the eph_pub prefix per §3.1, mandatory PROOF
receipts per §6.5 resolve the PacketReceipt. Sketches the RESOURCE
representation for oversize bodies and the backchannel-identify trick
that makes the link bidirectional.
flows/README.md status table updated.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
