In recent days there has been a mini media firestorm surrounding Google’s announcement about Willow, its new quantum computer, and a perceived threat to bitcoin. Most of the analysis reveals a remarkably surface-level understanding of how quantum computing will change cryptography, as well as how bitcoin remains resilient to these kinds of technological advancements. We’re going to take a deeper look at quantum computing and the threat it poses to bitcoin. It will get a tiny bit technical, but this is necessary to scratch the surface and understand what these latest developments really mean.In short, quantum computing will certainly necessitate a change to bitcoin’s protocol within the next few years, similar to the computer upgrades triggered by Y2K. It will likely be a complicated and time-consuming exercise, but not an existential threat to bitcoin itself. And it won’t only be bitcoin that’s affected, since what we are really dealing with is the ability of quantum computers to crack every kind of cryptography we use today across finance, commerce, banking, and more.
It’s hard not to wonder whether some of this alarmism about the end of bitcoin stems from a kind of “sour grapes” dynamic. Critics who have long eschewed bitcoin – whether because they don’t believe it could ever work, resent its challenge to government control, or simply regret not investing when it was cheaper – are seizing on Google’s quantum computing news to predict bitcoin’s downfall. These reactions often say more about the biases of the skeptics than the vulnerabilities of the bitcoin itself.
Not Just a Bitcoin Problem
Google’s Willow quantum computer can make calculations with 105 qubits, and its output is believed (as of now) to be relatively accurate. Although 105 qubits represents a large step up from previous quantum computers, breaking bitcoin’s encryption would require 200 to 400 million qubits. To reach this capability within 10 years, quantum computation would have to rise over 324% annually, which is far outside expectations.
Nonetheless, quantum computing is a threat to bitcoin that must be taken seriously, and bitcoin’s protocol will need be updated sooner than later. Conversations in the bitcoin developer community about when and how to do this have already begun. Once solutions come into better focus, a Bitcoin Improvement Proposal, or BIP, will be posted online for continued debate and experimentation. If and when it is chosen by the community for incorporation into the protocol, it will take effect once a majority of bitcoin nodes adopt it.
However, the changes coming to bitcoin to meet this challenge pale in comparison to what will be required of thousands of other secure computing protocols and networks. The effort to upgrade the entire world’s cryptographic protocols may well turn out to be an order of magnitude more complex than preparing for Y2K.
Focusing on how quantum computing will affect cryptocurrency misses th