A new gadget lets you replace passwords and other log-in methods with a wristband that measures your heart activity. It’ll be launched next year, with the makers hoping to strike deals with a variety of gadget manufacturers.

The device, Nymi, doesn’t actually measure your heart rate, which clearly changes depending on your activity. Instead it measures your cardiac rhythm, which is consistent: put in crude terms, if the heart rate is the “size” of your cardiac activity, the cardiac rhythm is the “shape.”

Each person’s cardiac rhythm is different as it is determined by both the size and position of your heart, and a study cited by The Economist suggests it doesn’t change significantly over at least a five year period.

The theory behind using this technology is that even compared with other biometric identification, cardiac rhythm is particularly secure. Not only are there major practical challenges to capturing somebody’s cardiac details without their knowledge, but it’s also tricky to use those details to try to simulate the way the rhythm presents in a real body.

When you put the Nymi wristband on for the first time, you clasp it to your wrist, then touch a sensor with the other hand. This completes a circuit through your body and, after around two minutes’ calibration, records your cardiac rhythm.

You can then link the wristband to devices and specific applications through Bluetooth, meaning they’ll only be authorized to work when within range of the wristband. The Nymi stops authorizing devices as soon as you take it off.

You’ll be able to set different ranges for different devices. For example, you could set a range of a few inches for a phone to make sure it can’t be used if you leave it on a table or in a bag while visiting a restroom.

The Nymi also supports six-axis motion gestures which you can customize. The manufacturers suggest one use would be to set the wristband to act as a remote keyfob for a car, but only when you move your wrist in a specific manner, meaning you can walk past the car without accidentally unlocking it.

The device is available for pre-order now at $79 for the first 25,000 orders (1,585 people had ordered at the time of writing), with the standard price being $99.