Bitcoin Magazine

The Quantum Issue: WTF Is Quantum Computing?

What is quantum computing? How is a quantum computer different from a regular computer? What relevance does this have to Bitcoin?

New Bitcoiners have been inevitably bumping into these questions and having to confront the issues they dredge up regarding Bitcoin’s exposure to what is very much an existential threat to its existence if a viable quantum computer were to be developed. 

The ability to own bitcoin rests on the foundational assumption that without directly leaking a copy of it, no one but the person who possesses a private key can sign to transact with coins secured by that key. Quantum computing calls that assumption into question. 

Quantum computers are not just “computers, but faster.” They function in a very fundamentally different way from a classical computer, and as such they are much more efficient than classical computers at very specific kinds of computations. Now obviously, I’m not going to actually explain how quantum computers work in minute detail within four pages, but I will give you the core intuition of how they are fundamentally different from a classical computer. 

So let’s take a look at how both kinds of computers interact with things like large cryptographic keys. 

Classical Computers

Everything stored in a classical computer (or just computer from here on out) is stored as a series of 1s and 0s. Each bit (1 or 0) is precisely a 1 or 0; there is no ambiguity. When a piece of data is stored, it’s 1s and 0s. When a piece of data is manipulated or modified, it is done bit by bit, step by step, on each 1 or 0. 

That is how a computer works. It linearly, one step after the other, modifies the discrete unambiguous pieces of data that it is storing. It can’t skip ahead, or shortcut (in terms of the steps it’s taking, not more efficient ways to do things mathematically), it has to go through the steps of whatever computation it is doing one by one. 

When you generate a private key using a computer, it acquires a random value (you inputting dice, general user input, randomness from device hardware, etc.) and stores that in memory as 1s and 0s. From there it has to multiply this value by the elliptic curve’s generator point to get a public key. This is accomplished with an algorithm, that boiled down to its most basic level, is literally instructions on what bits to take, how to modify them, what circuits to “push” them down on a physical level to accomplish that, and in the end put the new value that has been modified bit by bit back into memory. 

There are other steps to arrive at an actual valid address, but for the purposes of this article those are not necessary to go into (but they are just like the above step, just step by step instructions on how to modify 1s and 0s in memory). 

So what if someone wanted to use a computer to guess someone else’s private key? 

There are 2²⁵⁶ possible private keys. That’s 115,792,089,237,316,195,423,570,985,008,687,907,853,269,984,665,640,564,039,457,584,007,913,129,639,936 different possible keys. 

A computer would have to try every single one of those possible private keys, one after the other (or however many at a time it can do in parallel), step by step following the exact instructions above for generating keys. The more of them you try to check in parallel, the more computing power you need, with no ability to find any shortcuts around that cost. 

The less computing power you want to use, the more time it will take, the less time you want it to take, the more computing power you need. 

This is an impossible task to accomplish with a computer. On one side you have a computation cost that every computer on Earth is not enough to pay, and on the other side you have a cost in time that is so high every star in the universe would die before you checked them all. 

To actually accomplish your goal, you need another option besides checking one by one linearly or in parallel. That’s where quantum computing comes in.

Quantum Computers

Quantum computers don’t work with discrete states. Everything is precisely a 1 or a 0. The most basic piece of information in a quantum computer is a qubit (the quantum version of a bit). Unlike a bit, a qubit is in a superposition where it is both simultaneously a 1 and a 0. It only settles into one or the other discrete states when it is observed. 

This is one of the key building blocks that allow a quantum computer to compute differently. The other is entanglement. Qubits aren’t just stored in isolation, the physical atoms representing them and collapsing to a discrete state when observed are entangled together. This means when entangled atoms are observed and collapse to a single state, the entangled atoms collapse to the same state, no matter how far apart they are. 

Now here’s where things get weird, and I’m going to have to get a little hand-wavy; you should still walk away with an intuitive understanding of why quantum computers are fundamentally different from a classical computer. An algorithm on a classical computer is a set of instructions to take a specific set of bits, and step by step modify them according to the algorithm’s instructions, until finishing and outputting the finished set of new bits. So the algorithm step by step takes one discrete state and turns it into another. 

Qubits don’t store discrete states until they are observed and collapse to one. They store probabilities. When you have a set of qubits entangled of any given size (like in this hypothetical case 2²⁵⁶), each given possible state that it collapse to has a certain probability of collapsing to that given state. 

Quantum algorithms, rather than being step by step instructions to operate on discrete states, are a set of instructions on how to operate on those entangled qubits in a way that alters the probabilities of different outcomes. Constructive interference is used to increase the probability of a correct outcome, and destructive interference to decrease the probability of incorrect outcomes (note that this is NOT the noise or interference that makes it difficult for physical quantum computers to function accurately, that is a different concept). 

So while a classical computer would have to check each individual private key one by one to find the one matching a specific public key, a quantum computer can simply run a few times using the right algorithm and arrive at the correct answer. It does not do this by “checking all the possibilities at once.” It simply modifies the probabilities of what a superposition will collapse into. 

This is why a quantum computer could break the assumptions underlying elliptic curve cryptography, and a classical computer could not (and it is also why quantum computers are only useful for certain types of computations with a massive possible space of answer candidates to check). 

Don’t Panic

This fundamental difference between classical and quantum computation means, that yes, if a viable quantum computer is actually produced, that functions correctly, then the underlying assumption that secures all Bitcoiners’ individual bitcoin is broken. All of those funds are insecure. 

Yes, this is a serious risk if such a device is actually manufactured, and it works, but we are not entirely unprepared. We understand the problem, we understand the exposure, and a good number of possible solutions to many different facets of the problem are coming together. 

Breathe, and relax. Through the rest of this issue we are going to walk you through the whole problem. 

This piece is featured in the latest Print edition of Bitcoin Magazine, The Quantum Issue. We’re sharing it here as an early look at the ideas explored throughout the full issue.

This post The Quantum Issue: WTF Is Quantum Computing? first appeared on Bitcoin Magazine and is written by Shinobi.

Bitcoin Magazine

No Fork Required: Bitcoin’s First Quantum-Safe Transaction Just Happened

Should fund managers dealing in Bitcoin be worried about the threat of quantum computing? 

The short answer is yes — but there’s time to prepare and solutions are already being found.

One of them? Post-quantum Bitcoin transactions on the mainnet. And the first one happened this week thanks to the Starknet Foundation. 

JUST IN: The first post-quantum resistant Bitcoin transaction was mined today.

"It required no soft forks. It required no hard forks. It required no core protocol upgrades. And it's live today." pic.twitter.com/YyZbHhm8HI

— Bitcoin Magazine (@BitcoinMagazine) August 27, 2026

Speaking at Bitcoin Asia in Hong Kong on Thursday, Damian Chen, VP of growth at the Starknet Foundation, demonstrated how funds vulnerable to future quantum attacks can be secured without requiring a network-wide fork, thanks to the company’s latest solution. 

“This is a monumental moment,” Chen said. “This is the first post-quantum-resistant Bitcoin transaction on bitcoin mainnet today. It required no soft forks; it required no hard forks; it required no core protocol upgrades, and it’s live today.”

The transaction happened using a method created by StarkWare researcher Avihu Levy. It works like this: Bitcoin transactions sit briefly in a public queue before confirmation. During that window, they expose cryptographic material that a sufficiently powerful quantum computer could use to forge a signature and steal the funds before the transaction is confirmed.

But rather than accepting the first valid signature, his method generates millions of signature candidates until it finds one with a specific structural property that doesn’t expose that vulnerable material while waiting in the mempool. 

This “signature grinding” is deliberately computationally expensive — a single transaction takes hours to produce — but that cost is what makes it resistant to quantum shortcuts.

Touting Quantum safe Bitcoin transactions — dubbed “QSB” — to institutions, Chen said that even if attackers have a fund’s private keys, they couldn’t make a fraudulent transfer. 

“QSB introduces a new hash authorization, and so an attacker with a sufficiently capable computer, even if they have your exposed public key, even if they derive your private key from your public key, even if they try to use that to authorize a spend to move your coins out of your wallet, those things are not enough for them to do so,” he said. 

It’s worth noting that ordinary Bitcoin nodes currently don’t recognize this non-standard transaction format, so it couldn’t go into the public mempool and instead had to be handed straight to a miner willing to accept it — with mining company MARA’s Slipstream service being the one that mined the QSB transaction. 

Quantum researchers have warned that a time will come when Bitcoin’s software — which underpins the biggest and strongest computer network in the world — will need to be upgraded to deal with quantum computing. 

While some crypto VC firms have urged action, top Bitcoin developers have argued that many of today’s quantum computers have limited capabilities, and have only demonstrated trivial computations. 

Still, they have noted that their development could arrive unexpectedly — just like advances with artificial intelligence — and have started developing some solutions. 

Chen added: “The question to me has never been when will quantum arrive. We all know quantum will arrive at one stage, but the question to me has always been, how long will it take for you to be ready when quantum does arrive?”

This post No Fork Required: Bitcoin’s First Quantum-Safe Transaction Just Happened first appeared on Bitcoin Magazine and is written by Mathew Di Salvo.

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Google Cloud outlines its roadmap to full post-quantum cryptography readiness, with key milestones targeted for 2027 and 2028.

The post Google Cloud Sets Out Post-Quantum Roadmap With 2029 Readiness Goal appeared first on SecurityWeek.

Ethereum co-founder Vitalik Buterin has shared a comparison between Ethereum’s earlier roadmap and a newer L1 “Strawmap,” highlighting privacy and quantum safety as higher-priority research areas.

The post points to several notable changes, including more emphasis on native privacy requirements, keyed nonces, shielded pools, quantum safety, and a move away from Verkle trees toward Poseidon binary trees.

This should not be treated as a final Ethereum governance decision.

The L1 Strawmap is a planning and research tool, not a hard fork commitment. Ethereum’s roadmap evolves through research, implementation, client work, community debate, and eventual upgrade processes.

Still, when Buterin highlights privacy and quantum safety, the ecosystem pays attention.

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TL;DR

• Vitalik Buterin compared Ethereum’s older roadmap with a newer L1 Strawmap.
• Privacy and quantum safety appear higher in the planning stack.
• The post is research direction, not a binding governance decision.

https://x.com/VitalikButerin/status/1822262973950150965

Why Privacy Is Moving Up

Ethereum’s privacy problem has always been obvious.

Public blockchains are transparent by default. That is useful for auditability, but it creates problems for payments, payroll, trading, donations, enterprise activity, identity, and personal financial data.

Most ordinary users do not want their full financial history visible to anyone who knows their wallet address.

That is why native privacy keeps returning as a roadmap priority.

Keyed nonces, shielded pools, and related tools can help make privacy more practical at the protocol or application layer. The challenge is balancing privacy with compliance, usability, scalability, and security.

Ethereum has avoided quick fixes because privacy is not just a feature. It affects the whole user model.

Quantum Safety Is Becoming Less Theoretical

Quantum risk has long felt distant.

But serious roadmaps need to think in years, not weeks. If quantum-capable attacks become practical later, networks with enormous value secured by cryptographic assumptions will need transition plans before the threat becomes immediate.

That is why moving quantum safety higher in the research stack matters.

It does not mean Ethereum is about to be broken by quantum computers. It means the ecosystem is planning for a future where today’s cryptographic assumptions may need updating.

That kind of preparation is exactly what long-lived base layers should be doing.

The Verkle-To-Poseidon Shift Is Technical But Important

The roadmap comparison also points to a shift away from Verkle trees toward Poseidon binary trees.

For many users, this sounds deeply technical, and it is. But these data-structure choices affect how Ethereum handles state, proofs, scalability, and future compatibility with advanced cryptographic systems.

Ethereum’s roadmap has always involved hard trade-offs.

A design that looks attractive in one phase may become less attractive when research evolves. The move toward different tree structures suggests the research community is refining assumptions around proof systems, performance, and long-term upgrade paths.

That is normal for Ethereum, but it can feel messy from the outside.

Not A Hard Fork Announcement

The key caution is that roadmap discussion is not the same as scheduled activation.

Ethereum does not change because one post says it should. Changes require implementation, testing, client support, community acceptance, and coordination across the ecosystem.

The L1 Strawmap helps guide thinking.

It does not force validators, developers, apps, or users into a specific upgrade tomorrow.

That is why the right framing is research direction, not policy.

Ethereum’s Long-Term Priorities Are Changing

The bigger story is that Ethereum’s priorities are maturing.

The network has already moved through proof-of-stake, scaling layers, fee-market upgrades, and execution improvements. The next decade of Ethereum may focus more on privacy, security against future cryptographic threats, state management, and making the base layer sustainable for billions of users.

That is less flashy than a new DeFi cycle, but it is arguably more important.

Ethereum is trying to become durable infrastructure.

Buterin’s Strawmap comparison gives a window into what that durability may require: stronger privacy, quantum-aware design, and a willingness to revise technical plans when better options emerge.

This article is based on Vitalik Buterin’s public Ethereum L1 Strawmap comparison.

This article was written by the News Desk and edited by Samuel Rae.

This report is based on publicly available market and on-chain data. at X