February 16, 2023

Did the Quantum Apocalypse really arrive on January 4th?


This is a brief post in response to the current focus on the topic. Something longer will follow.

Q: Will quantum computers defeat encryption?

A: Yes, certain types on encryption, including many that are in common use today.

Q: Do we see that as an immediate, existential threat?

A: No. Or, at least we didn’t a few weeks ago as the timeline for suitable quantum computers to be here was “years away”. The recent paper published by researchers in China has raised some interesting questions.

The paper was published a few weeks back but the news got into the mainstream press on 4 Jan and my inbox has been buzzing ever since.

If you haven’t heard about it, this article by Alexander Martin in The Record gives a useful (albeit quite technical) summary, including the reasons experts are sceptical.

If you’re interested, what next?

Have a read of the summary below, it’s just a few minutes. If it piques your interest as a topic the next point could be either my business-executive-friendly primer is available here (UK) or here (US) or here (on Medium))

Or if you want something more technical this piece on Quantum Attack v Quantum Defence.

Some context

In 1994 Peter Shor spiced up the nascent world of quantum computing theory by presenting an approach (now simply referred to as Shor’s Algorithm) that would allow quantum computers to crack certain types of mainstream encryption.

This was important insofar as it was one of the first specific ‘use cases’ for quantum computers. It was also highly theoretical as the hardware required to execute was in the far distant future.

What is important to understand is that just about any encryption can be “decoded” mathematically. It’s just that it takes an awful lot of calculations and, even with the use of today’s strongest super computers, that means then even basic encryption can take years, decades or even millennia to decode. The way quantum computers do certain mathematical calculations makes them millions of times more efficient. However, the only quantum computers currently available are very early versions which people have never thought suited to apply Shor’s Algorithm in an effective manner.

It’s a bit like what we see with data transfer: these days we get frustrated if it takes more than a minute or so to download a two-hour video to our phone or tablet. In the 1990s when I first started travelling for work I was excited to get a 14.4KBps modem download speed. That meant synchronising Lotus Notes (there was not Outlook in those days) could require a full hour if there were even just 3 or 4 modest PowerPoint attachments. This was the norm. When Broadband came along, measured in MBps, things were far far better for email but we still didn’t dream of downloading full videos or music albums in moments.

That is where we are supposed to be now with Quantum Computers. Despite the incredible achievements of the past decade it is still early days. We call it the NISQ era (more here) as in Noise Intermediate-Scale Quantum, because the number of qubits and their quality is low.

This is supposed to be the period we move to detailed ideas of how we use quantum computers in the business world once they are available. (See e.g., the work that people like Esperanza Cuenca Gomez are doing at Multiverse Computing). It’s not the year we’re supposed to be seeing them truly “in action”.

Therefore the news that researchers have identified how to break a 2048-bit algorithm using a 372-qubit quantum computer is startling. IBM has machines that already have more qubits than that.

Find Medium's full article here.