Access security in the smart home: roles, double confirmation, PIN hashing and audit

When one screen controls doors, garage, alarm and climate, the question is no longer "does it look nice" but "who is allowed to touch it". Access security in HoumeOS is built in, not bolted on.

Three roles, clear boundaries

The decision of who can do what is made on the server, not in the browser — the interface only shows what the rights allow.

• Administrator — everything: devices, modes, rules, profiles.
• Household — lighting, climate, irrigation, energy, security, doors and scenarios; but not the configuration of the home.
• Guest — only lighting and scenarios. Locks, garage, gate and alarm are inaccessible.

Everyone has exactly as many rights as they need — this is the principle of least privilege.

Double confirmation for critical actions

Unlocking a door, opening the garage, disarming the alarm — all of these ask for a second confirmation. An accidental touch of the screen cannot open the house. The system returns a "critical action without confirmation" state and nothing executes until you confirm it. More on security and hazard scenarios in Smart alarm and hazard scenarios.

How we store PINs

PIN codes are never stored in plain form. They are kept as a salted hash with the slow, well-established scrypt function, and the comparison is resistant to timing measurement (constant-time). Additional safeguards:

• after 5 wrong attempts a pause kicks in (too many wrong PINs);
• the screen locks automatically on inactivity;
• the session expires after a set interval without activity.

Security is in the details — and in the fact that no screen exposes the administrative interfaces directly to the internet; the channel remains the local network.

Who did what

Logins, logouts, denied rights, denied confirmations and accepted commands are recorded in the journal with name and role. When something happens in the home, you have a clear answer of who did it and when. This is an audit, not a guess.

What this means for you

• Children and guests use the screen calmly — they cannot unlock the front door.
• No accidental actions on the critical devices.
• Your passwords are nowhere in plain form — even if the database leaks, the PINs stay protected.
• There is a trail — every more serious event can be traced.

The security of the home begins with control over the control. That is why rights, confirmations and audit are part of the platform from the ground up — not an add-on module.