Sec // End-to-end
The relay is blind
Your browser and your box run an authenticated key exchange through the relay.
The relay forwards frames it cannot read: it never receives your access password, so it
cannot derive the session keys.
- Key exchange
- X25519, ephemeral — a fresh keypair on both sides, every session.
- Authentication
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Your access password is stretched with HKDF-SHA256 into a pre-shared key that
is mixed into the key schedule (an NNpsk0-style pattern).
- Transport
- AES-256-GCM — a separate key and counter for each direction.
- Relay sees
- Ciphertext and routing metadata. Nothing else.
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Forward secrecy
Session keys are ephemeral. Recorded traffic stays unreadable even if the access
password leaks later.
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Mutual authentication
Without the password neither side can produce a valid confirmation tag, so a
man-in-the-middle — the relay included — is rejected before any data flows.
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Replay protection
Every frame carries a strictly increasing counter. Repeated or reordered frames are
dropped.
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Session cap
A tunnel closes automatically after 4 hours.
The access password grants full control of the machine you connect to. Never enter one
that someone else gave you — no legitimate operator will ask you for it.