1  //! Relay server protocol and client.
 2  //!
 3  //! This module implements the relay protocol for asynchronous message delivery.
 4  //! Relay servers act as message stores, allowing messages to be delivered even
 5  //! when the recipient is offline.
 6  //!
 7  //! # Architecture
 8  //!
 9  //! ```text
10  //! ┌─────────────────────────────────────────────────────────────┐
11  //! │                    Relay Protocol                           │
12  //! │  - WebSocket-based communication                            │
13  //! │  - Public key registration for mailboxes                    │
14  //! │  - End-to-end encrypted message storage                     │
15  //! └─────────────────────────────────────────────────────────────┘
16  //!                          │
17  //!          ┌───────────────┼───────────────┐
18  //!          ▼               ▼               ▼
19  //!   ┌─────────────┐ ┌─────────────┐ ┌─────────────┐
20  //!   │  Register   │ │    Send     │ │   Fetch     │
21  //!   │  (mailbox)  │ │  (relay)    │ │ (retrieve)  │
22  //!   └─────────────┘ └─────────────┘ └─────────────┘
23  //! ```
24  //!
25  //! # Security Model
26  //!
27  //! - Messages are end-to-end encrypted before reaching the relay
28  //! - Relay sees only: sender public key, recipient public key, encrypted blob
29  //! - Relay cannot read message contents
30  //! - DHT stores relay locations, not messages
31  
32  pub mod client;
33  pub mod gossip;
34  pub mod protocol;
35  
36  pub use client::{RelayClient, RelayError};
37  pub use gossip::{BloomFilter, GossipHandler, GossipResponseResult};
38  pub use protocol::{GossipForwardedMessage, RelayMessage, StoredMessage};