The sleek silicone bracelet you see above isn’t yet another fitness tracker. It’s a new “wearable authentication device” called Nymi, and its creators think it can replace your passwords and keys — or at least make them a whole lot more secure.

Clasp the Nymi around your wrist, press your fingertip to the sensor on the top, and it springs to life. Built-in LEDs and a vibration motor let you know it’s active, and you can also program them to deliver notifications from your smartphone (Nymi supports Bluetooth 4.0).

Nymi authenticates you by reading your heartbeat the way an electrocardiograph does: by monitoring its electrical activity. That gives Nymi a significant advantage over other wearables like the NFC ring our own Russell Holly tried out.

Even if someone was to swipe your Nymi, it wouldn’t be any use to him or her. Without sensing that your heart is thumping out its specific pattern, your Nymi won’t authenticate. It’s got proximity sensors, too, so you don’t need to worry about someone flicking through the contents of your phone while you’re in the bathroom. Nymi knows to unlock your device when it’s close to your wrist.

Initially, Nymi will support Windows, OS X, Android, and iOS, allowing you to unlock your device and log in to apps and websites without pressing a key. Bionym, the company behind Nymi, has much bigger plans for the inexpensive authenticator, though.

It wants to convince other hardware manufacturers — from companies like Samsung that build smart appliances to Tesla Motors — to integrate Nymi support into their products. The bracelet offers basic gesture-recognition support, so it could easily do things like change the radio station in your car with a wave, or lower the temperature on your Nest thermostat with a turn.

Right now, you can pre-order one of the first Nymi units for just $79. After that, they’ll sell for $99. That’s still not a bad deal when you consider just how much this inconspicuous little bracelet can boost your device security.