Protocol Concepts
Understand the ECCP stack, device identity, homeservers, clients, and Layer 4 integrations.
Protocol Concepts
ECCP is easier to reason about if you keep the four layers distinct.
The Four Layers
| Layer | Purpose | | --- | --- | | Layer 1 | Protocol rules: encryption, federation, sync, event semantics | | Layer 2 | Homeservers and nodes implementing the protocol | | Layer 3 | Clients such as PrivChat and exine | | Layer 4 | Shadow Rooms, Bot API hosts, and Bridges |
Homeserver
A homeserver stores local room state, validates signatures, serves the client API, and participates in federation. It should not redefine the protocol.
Client
A client turns cryptographic and operational complexity into a user experience. PrivChat hides most of that complexity; exine keeps it visible for operators and developers.
Device Identity
ECCP identifies users through accounts and devices separately. That split lets implementations rotate access tokens without pretending a new device is the same trusted endpoint as an old one.
Bridges and Bots
Bridges and bots sit above the protocol. They add value, but they are not the network's source of truth.
Cryptographic Vocabulary
- X25519 for device key agreement
- Double Ratchet for message chain updates
- HKDF-SHA256 for deterministic key derivation
- Signed federation envelopes for server-to-server authenticity