Soon, you'll have the option of locking your bitcoin wallet with your heartbeat.

A Canadian startup says it's just a few months from shipping the Nymi, a wristband that can learn the unique sound of your heartbeat and use it to open and close your bitcoin wallet.

A bitcoin wallet is the software you use to send and receive bitcoins – home to the private cryptography key that provides access to your bitcoin, and it's rather important that you keep this key safe. Bitcoin, the increasingly popular digital currency, works a lot like online cash. When someone steals your bitcoin, the money is gone for good. You can hide your key behind a password on one of the popular online wallet services, but you might want to take additional steps, like hiding it on a piece of paper in your desk drawer here in the real world or using your heartbeat to lock it down on your PC.

Bionym, the company that makes the Nymi wristband, markets it as a simple-to-use log-on device. Basically, it provides a biometric alternative to a password, using Bluetooth wireless signals to send your heartbeat signature to all sorts of computing systems where you need security, including your PC, your iPad, even your car.

Because your electrocardiogram, or ECG, readings are both hard to spoof and unique, Bionym thinks these little plastic wristbands will open up a whole new era of fun, password-free living – as you can see in this fantasy demo video:

Bionym is now taking orders for the Nymi, which sells for $79 and will come with its own bitcoin wallet, the company says. The wallet's private key lives on the wristband, encrypted, so if you lose the device, you could lose access to your bitcoins. But the wallet will also provide a way of backing up your key on an offline device.

Though Bionym has elected to build its own bitcoin wallet, the company could integrate the Nymi with existing wallets, such as those built by Coinbase or Blockchain.info.

Nymi measures heart-wave characteristics that are constant, Bionym says, so the device will work whether you're nervous or sleepy or you've just finished exercising. "The Nymi is a very natural device to use as a bitcoin wallet," says Vahlis, Bionym’s chief cryptographer. "If you do want to make an outgoing transaction, the user will have to perform a physical confirmation by tapping on the wristband."

Of course, you have to keep the thing on your wrist for it to work. But that's better than losing all your bitcoin.