feat:added mesh 1.0

[vinaysingh8866]

Mesh Networking Protocol 1.0

Summary

Adds the Mesh Networking Protocol v1.0 — a DIDComm v2 protocol that enables agents to form ad-hoc peer-to-peer mesh networks over BLE and LoRa transports without internet connectivity.

• Nodes discover peers via Ed25519-signed announcements and build a distributed topology graph
• Multi-hop relay with TTL-based controlled flooding and degree-adaptive jitter to prevent broadcast storms
• Topology-aware shortest-path (BFS) routing for directed unicast messages
• Packet deduplication via LRU cache prevents replay and flood amplification
• Fragmentation support for MTU-constrained transports (BLE ~512B, LoRa ~200B)
• Graceful leave notifications for immediate topology updates

Protocol Details

PIURI: https://didcomm.org/mesh/1.0

Messages:

• announce — Periodic signed broadcast advertising presence and neighbor list
• relay — Wraps a packed DIDComm message for multi-hop mesh delivery (supports broadcast and directed modes)
• leave — Graceful departure notification with signature verification

Key Design Decisions:

• 8-byte Routing IDs derived from SHA256(ed25519_public_key)[0..8] keep packet headers compact while maintaining cryptographic binding
• No DIDs are broadcast over the mesh — identity exchange is handled separately via OOB protocol
• All relayed payloads are opaque (already DIDComm-encrypted), so intermediate nodes cannot read message content
• Degree-adaptive jitter scales relay delay with peer count (10-220ms) to reduce storms in dense networks
• Bidirectionally confirmed edges only — both peers must claim each other as neighbors for a route to be valid

Security

• Ed25519-signed announcements with routing ID binding prevent topology spoofing
• Stale announcement rejection and deduplication prevent replay attacks
• Payload encryption is handled by DIDComm — the mesh layer never sees plaintext
• Only compact routing IDs appear in headers, never DIDs

Changes

• site/content/protocols/mesh/1.0/readme.md

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[TheTechmage]

Discussed in Today's UG meeting, merging. Any followups can be addressed in PRs