One of the benefits of cryptocurrencies is that they’re safe. The coins are digital so they can’t be swiped from your pocket or stolen from your home, and to use them, you need two long pieces of code that can never be cracked.

Each of those lines of code functions as a key. The public key is like an email address. It tells people where your wallet is so that they can send funds to you. You want people to have that key. The private key is like a password. You use that key to send funds from your wallet—and you need to look after it.

Anyone who has both your private key and your public key can access your funds and empty them into their own account. And because there are no refunds in the cryptocurrency world, once your money is gone, it’s usually gone forever. In the first half of 2018 alone, more than a billion dollars’ worth of Bitcoin were stolen, much of it by hackers who managed to sneak malware onto people’s computers to copy their private keys.

As long as your computer is attached to the Internet, it’s vulnerable. And as long as you have your private keys on your computer, they’re vulnerable.

There are a number of steps that you can take to keep your keys safe.

One option is to store them on an air locked computer. This is a computer that has no connection to the Internet. The Wi-Fi is off and the data cable is out. The only way to get to the keys will be to steal the machine.

But people like to connect their computers to the Internet and using an old machine as a vault can be dangerous: they have a habit of breaking down. If you can’t boot up a computer with a private key, you can’t access your funds.

There are better hardware options. Companies like Trezor and Ledger produce dongles that look like large USB sticks but which securely hold your private keys. They can’t be hacked and they were designed for cryptocurrency. They’re not cheap. Prices start at around $50 but if you’re keeping a lot of money in digital coins, they’re a good investment.

Alternatively, you can use Cryptosteel, a device about the size of a mobile phone that looks like a printer’s block. You load your private key one character at a time into the device on small, steel rectangles then lock the code in place. While devices like Trezor and Ledger depend on electronics that can be damaged, Cryptosteel is entirely analog. If your house burns down, you’ll be able to dig your Cryptosteel out of the ashes, pull out your Bitcoin and buy a new house.

You certainly won’t be able to do that if you’ve stored your keys in a paper wallet. That’s just a fancy way of saying that you’ve written it down or printed it out on paper. Sure, a paper wallet can’t be hacked but it can be destroyed and lost.

In the end, there’s no such thing as complete security. There is such a thing as complete responsibility though, and when it comes to safeguarding our assets—including our crypto assets—we all need to take responsibility for protecting ourselves.

Joel Comm is New York Times best-selling author, blockchain enthusiast, professional keynote speaker, social media marketing strategist, live video expert, technologist, brand influencer, futurist and eternal 12-year old. His latest project is as co-host of The Bad Crypto Podcast, a top cryptocurrency show making the future of digital payments easy to understand.