I stumbled on a shocking piece making the rounds on social media. It’s a fascinating example of how hype or doom can be manufactured so quickly over such a fundamental misunderstanding (or deception). The article was a piece in Fortune titled "Bitcoin would need over 300 days of downtime to adequately defend itself from the ‘imminent’ threat of quantum computing, research finds".
Here is the offending paragraph:
A study from the University of Kent’s School of Computing calculated that if Bitcoin were to try to effectively protect itself from the threat quantum computing poses, it would take a protocol update that would take the cryptocurrency offline for 76 days. More realistically, the study calculated, Bitcoin would instead designate 25% of its server to a protocol update and allow its users to continue to mine and trade at a slower rate. But in that scenario, the downtime would take about 305 days. That’s 10 full months.
Please point to me where the Bitcoin server is, Fortune.
I was immediately perplexed about this article because anyone who spent time following the blocksize war in Bitcoin would know that upgrades happen without downtime. I was even more surprised to read the linked paper from the Kent’s School of Computing, which also seemed to have this knowledge gap.
Proverbially, this is easier said than done. Any upgrade to a current-day cryptosystem to make it quantum-secure comes with an all-but inevitable downtime.
It’s funny how this line in the paper doesn’t have a citation. I genuinely have no idea why the authors of the paper put this in writing. The only scenario I can imagine this being plausible is if a powerful entity had kept an advanced protype quantum computer secret and their first observable act was to take on Bitcoin. Is it possible, sure…
But not only is this not particularly likely, but there would most definitely be other signs on the way. In that scenario, Bitcoin is already toast, as the trust in the system will be gone entirely and it would be pointless to even attempt such an upgrade. There are many other scenarios where the Bitcoin network has time to upgrade. None of these scenarios involve downtime. The truth of the matter is that this paper fundamentally misunderstands how decentralized networks operate, which makes me have serious questions about the state of academia.
I’ve been meaning to follow-up on the Bitcoin conversation I had the pleasure of participating in on Geopolitics & Empire. Not only has it sparked many intense debates within my friends and associates, but there’s also been a much wider discussion on Bitcoin’s role in shaping the future of the US dollar and even digital currency systems. I believe there are some fundamental pieces of information that should be wider understood as this conversation progresses. It is clear, that there is a significant hunger for a deeper understanding on this topic.
The basics
Quantum computing hype
Google’s new Quantum Chip ‘Willow’ has reached a new milestone of cracking a key challenge in a tiny fraction of the time it would take an ordinary machine. This is due the fact that quantum computers process information in a much different way than classical computers do. The idea is that these differences can potentially find answers to hard-to-compute problems. Of course, these differences have profound security implications.
Encryption apocalypse
Encryption uses math to protect information. To the degree quantum computers are vastly more powerful at the kinds of math used to protect information, they can be much more capable at reversing that math. In theory, this could be used to break many forms of encryption used today in online banking, websites, and even Bitcoin. As such powerful forces across the world are not only racing for Quantum Supremacy, and having the most quantum computing power, but also for having the strongest post-quantum cryptography, to protect their secrets.
This has profound impacts for cryptocurrencies, which all function due to cryptographic math. If quantum computers to become practical to use for breaking all kinds of cryptographic functions, than only “post-quantum” cryptocurrency projects will be able to withstand the onslaught. Of course this is not unique to cryptocurrency. Governments across the world have been collecting people’s communications on a “harvest now, decrypt later” basis that will absolutely give those interested in historical mass surveillance an unprecedented insight into people’s lives.
To make matters worse, all digital communications and security would be impacted in this scenario. A nation or corporation using such computing power for their own interests would effectively have the ability to read any intercepted communications. Online finance, and other institutions already have to solve these problems, just differently than cryptocurrencies.
A Bitcoin post-quantum upgrade
The punchline is that Bitcoin could absolutely upgrade to post-quantum cryptography with zero downtime. The paper, and the article(s) written about it are fundamentally misunderstanding how upgrades work in a decentralized network. Unlike centralized services, where the service provider can use a load-balancer to seamlessly migrate users to an upgraded system, decentralized networks have to handle things differently. The benefit of a decentralized protocol is that no single entity can shut down, disrupt, or modify the network, the idea of “downtime” for upgrades makes little sense.
Bitcoin, and every other blockchain based system has an advantage. Every block is an approximate for time and can be programmatically used to trigger certain events. Here’s a step-by-step walk-through of how a post-quantum upgrade of the Bitcoin network would work:
- The developers would agree on one of likely many solutions to migrate Bitcoin’s addresses, and security to new post-quantum cryptography.
- The ecosystem developers would then modify their Bitcoin software to “switch over” to the new cryptography after a certain time, defined by a specific block in Bitcoin’s blockchain.
- Operators would then on their own time, without any downtime to the wider network, upgrade their software.
- Eventually, once time passes to reach the selected block in the blockchain, everything running on the Bitcoin network switches over to the new cryptography and continues running as normal.
But it can’t be that easy right?
Here’s the rub, that’s a possible, but simplified & idealistic scenario. At minimum, you’d want to not hinge all the massive changes on a single hard fork. It presumes that all participants are enthusiastically pleased with the desired solution. In the past, controversial changes to the Bitcoin network have torn the community apart. But why would anyone reject this upgrade? Surely everyone in Bitcoin wants to have quantum-safe Bitcoin?
Imagine a hypothetical scenario where there is not one single post-quantum cryptography solution, but a variety. Instead of everyone making the choice between making the upgrade or not, maybe there are multiple competing proposals. Consider that the technical details, may be relatively minor, but we’ve already seen how social media can be weaponized to turn minor misunderstanding into horror and rage. With many competing scenarios, even assuming them all to be genuine finding consensus on the solution long-term is a non-trivial task.
These different directions would likely be not only incompatible with each other, but by design they would all have to be incompatible with the way Bitcoin has run since its inception. This means that the post-quantum upgrade to Bitcoin must be a hard fork, any software not applying the upgrade will effectively be running a completely different system.
Given how the Bitcoin community has handled scaling & privacy, I am pessimistic that they could actually perform a migration to post-quantum cryptography. This is not the same as saying that it’s impossible. Given the amount of wealth in the Bitcoin ecosystem, I imagine there’s quite a bit of incentive to get it right. But this highlights Bitcoin’s fundamental weakness, it will always be vulnerable to manipulation of people influential in the community.
The mere idea of post-quantum Bitcoin splitting into a couple or several different parallel hard-forks would be absolutely disastrous for the long-term health of the project. On the other hand it’s possible that entities interested in resolving problems in Bitcoin could take advantage of the hard fork opportunity to correct other problems as well. In that scenario you would likely see different post-quantum Bitcoin networks diverge into entirely different projects, which could be a great thing in the long run. Bitcoin successfully migrating to post-quantum encryption would be a historic accomplishment that would be very difficult to overstate. If the Bitcoin community successfully completes a post-quantum upgrade hard-fork I will certainly be recanting some of my harsher words regarding how I see the community …but I won’t be holding my breath.
But what is the real Bitcoin killer?
The ongoing discussion around Bitcoin and its future is lacking some very important wider context. It is my personal belief that the major powers in the world are preparing (but not yet initiating) a global-scale World War 3. Bitcoin ‘maximalists’ would argue that this can potentially be avoided if countries can replace brutal and bloody wars with softwar. The simplest argument for this idea is that if entities can become more wealthy peacefully enriching themselves off Bitcoin, why would they commit acts of aggression to get less?
I believe that only analyzing human warfare at the economic level is reductive. One could ask, “If Bitcoin hasn’t stopped any wars yet, when will it start stopping wars?” If not at 100K USD, will it need to reach 1M USD? How about 1 Billion USD? I’m sure many would consider outright astronomical numbers a bargain to end wars forever, but wars may yet come. When wars get hot, many things quickly get pushed off the table. A scenario where World War 3 escalates despite Bitcoin is one where its utility is drastically limited.
Bitcoin (and every other cryptocurrency) inherits circumstances downstream of our technological landscape. No matter how well designed and robust the Bitcoin network can be, there are fundamental realities that it relies on and must contend with. In an open warfare scenario, not only is energy likely to be rationed away from independent operations, but computing power is already aggregated into clusters. This means that while the network itself may be able to operate in the most dire of circumstances, access can certainly be restricted and manipulated by strong forces in wartime. To the degree Bitcoin can be a threat to opposing powers, it can also be a target.
Regardless of what the future holds, it is crucial that we consider the fundamentals of our technological landscape. Cyberspace itself must have fertile ground for supporting peaceful innovation, lest we surrender it all to the Military Industrial Complex. Bitcoin and many other great and useful technologies, serve effectively no purpose if digital freedom as we know it is extinguished by warmongers. It matters not where you fall on Bitcoin being benevolent or malevolent, it is time to ask what is the future of cyberspace and where does that put us?
