Without quantum security, our blockchain future is uncertain

News that two teams of Chinese scientists have achieved quantum advantage — a technical term for when a computer can perform functions beyond that of a classical computer — may be the signal that we have truly entered a new era. While Google’s 54-qubit quantum processor, Sycamore, became the first widely known example of early-stage quantum computing, the latest news out of the University of Science and Technology of China in Hefei is the best proof yet that we have crossed the information rubicon.

But despite many reasons to be excited by these developments, there are reasons to be concerned, too. While we might all eagerly await the day when we can predict traffic jams, consign animal testing to the history books, or pinpoint someone’s likelihood of getting cancer and then engineer a unique treatment⁠ — all in seconds ⁠— its tremendous power has a dark side.

Perhaps most terrifying for a society so reliant on the internet, quantum-level computing puts all of our digital infrastructures at risk. Our contemporary internet is built on cryptography⁠ — the use of codes and keys to secure private communication and storage of data. But for cryptocurrencies like Bitcoin (BTC) and Ether (ETH), for whom this concept is fundamental, one sufficiently powerful quantum computer could mean the theft of billions of dollars of value or the destruction of an entire blockchain altogether. With digital signatures suddenly easily forgeable, the very concept of wallet “ownership” will seem quaint.

Related: Talking digital future: Quantum computing and cryptography

When I first pioneered digital currency in the late 1980s, quantum computers were merely a theoretical proposition. While we were all aware of its inevitable arrival (those who work in tech are often keenly aware of the future barrelling towards us at breakneck speed), in a world where we hadn’t even seen the first web browser, we didn’t spend much time contemplating what seemed even then like deep-future technology.

Vulnerability to quantum computing

Times have changed, however. Over the next three decades, cryptocurrency would be refined and come to store nearly $3 trillion of value. One analysis by Deloitte found that over 25% of all Bitcoin could be stolen in a single attack, which at the time of writing amounts to nearly $300 billion. That would make it three-thousand times more lucrative than the next best heist. When you consider that 10% of the world’s GDP is expected to be held in cryptocurrency by 2025, this vulnerability quickly goes from concerning to terrifying. Not only is quantum computing around the corner, but we’ve never been more vulnerable to it.

Moreover, history shows us that it isn’t just hackers, cyber-terrorists and criminal organizations we should fear, but governments, too. The Chelsea Manning and Edward Snowden revelations of the last decade showed the world what the most powerful government on the globe could (and would) do when nobody was looking. Authoritarian powers like Russia and China have their sophisticated methods of coercing and controlling their populations. Quantum computing would only supercharge their tyranny.

While we already know of a few examples of early quantum computing, to bet against a state-level actor getting their hands on a highly-developed quantum system before a private organization would be foolish. And when they do get this technology, they won’t just be coming for your Bitcoin. They will be reading your messages, and every email, IM or document you ever sent using the old cryptography; now accessible with their new quantum master-key.

Is there a solution?

The puzzle we face moving forward is how to make ourselves safe from their devastating potential. My team and I at the xx network have spent the last few years pioneering our quantum-secure blockchain as one way to solve that problem. Adding another layer of privacy protection with our flagship metadata-shredding DApp, xx messenger, will be another way to guard against quantum-armed malicious actors. There will be other solutions by different innovators, they just aren’t coming fast enough.

There are reasons to think that the coming quantum-computing revolution won’t torpedo our chances of a new, decentralized world built on the blockchain. For one, the National Institute of Standards and Technology in the United States is already considering 69 potential new methods for “post-quantum cryptography,” and expects to have a draft standard by 2024, which could then be rolled out across the internet.

There are also very few cryptographic techniques that would be completely redundant in a post-quantum world. The key agreement protocol and digital signatures are the most glaringly vulnerable, and innovations such as lattice-based cryptography provide us with ready-made solutions to implement in the next generation of blockchain technology, and there are even stronger techniques known as well.

While a large-scale quantum computer of…