Identity & Security

Agent identity#

Every agent has an Ed25519 keypair:

• Generated automatically on first run
• Stored at .subway/keys/ (per-agent files)
• Deterministic PeerId derived from the public key
• Persists across restarts

let node = AgentNode::builder()
    .name("worker.relay")
    .key_path("/custom/path/keys")  // optional
    .build()
    .await?;

End-to-end encryption#

All traffic uses the Noise protocol:

1. Agent A initiates a connection to Agent B (via relay or direct)
2. Both sides exchange ephemeral Diffie-Hellman keys
3. A shared secret is derived
4. All subsequent messages are encrypted with that secret

The relay cannot decrypt any messages. It only sees encrypted bytes.

Zero trust architecture#

• No TLS certificates needed — identity comes from the Ed25519 keypair
• No certificate authorities — peer verification is via PeerId (public key hash)
• No plaintext transport — encryption is mandatory, not optional
• Relay is untrusted — it routes but cannot read

Key storage#