RFC-0003: CNK frames & PQ envelope

Mesh frame

Postcard MeshFrame { header: FrameHeader, body } with length-prefixed datagrams for smoltcp/UDP.

msg_typeMeaning
1HEARTBEAT
2TX_LOG_SYNC
3PQ_HANDSHAKE
4TASK

PQ handshake messages

  1. HybridHello — KEM EK, DSA VK, nonce, puzzle challenge
  2. HybridReply — KEM CT, DSA VK, nonce, puzzle response, DSA signature, transcript hash
  3. Both parties derive SHA3-256(ss || transcript) as session key material

TxLog sync

Neighbor replicas exchange encoded TxEntry lists; receivers merge_replica only contiguous extensions of the local tip (no fork choice yet — scaffolding).