👻 Ghostline

Encrypted terminal conversations through a small Rust relay.

Ghostline pairs two terminal clients with a temporary invite key, exchanges encrypted profiles, and relays encrypted chat frames without giving the server message plaintext.

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How it is structured

Crate	Role
ghostline-client	Ratatui interface for creating and joining invites, choosing contacts, and chatting.
ghostline-server	Tokio TCP relay that pairs users by room key and forwards encrypted message frames.
ghostline-core	Shared operation codes, identifiers, room keys, frame sizes, and protocol helpers.

Security model

🔐 Messages	Encrypted client-side with ChaChaBox; every message uses a fresh ephemeral key pair and nonce.
🗄️ Local data	Friend information, room keys, chat keys, and history are protected with XChaCha20-Poly1305 using an Argon2-derived key.
🌐 Relay	Routes room and message frames but does not decrypt chat contents.
🧹 Secrets	Private and derived key material uses zeroization where implemented.

Experimental: Ghostline has not been independently audited. The current handshake does not provide an out-of-band identity verification step, so do not treat this prototype as production-secure messaging.

Run locally

Ghostline currently uses 127.0.0.1:1278, so start the relay and clients on the same machine.

1. Start the relay

cargo run -p ghostline-server

2. Create an invite

cargo run -p ghostline-client -- --invite

3. Join from another terminal

cargo run -p ghostline-client -- --join <invite-key>

4. Open a conversation

cargo run -p ghostline-client -- --talk

Running the client without arguments opens the interactive menu:

cargo run -p ghostline-client

Local data

Path	Contents
~/.ghostline/user_id	Persistent random user identifier.
~/.ghostline/friend_ids.toml	Encrypted friend store, room keys, chat keys, and message history.

The client prompts for a storage password. For non-interactive local runs, it can be supplied through GHOSTLINE_STORAGE_PASSWORD; remember that environment variables may be exposed to other processes or tooling on the machine.

Current limitations

• The relay address is the compile-time SERVE_IP constant; there is no runtime config or deployment profile yet.
• Rooms exist only in server memory and disappear when the relay restarts.
• Invite keys are temporary connection secrets and must be shared through a trusted channel.
• The protocol and stored-data format may change while the project is a prototype.

Development

cargo fmt --all --check
cargo test --workspace
cargo clippy --workspace --all-targets

_{Quiet transport. Private words.}