Is quantum computing a threat to bitcoin? Yes, but not today. No quantum computer can break bitcoin yet. A future machine running Shor's algorithm could work out private keys from public keys already visible on the blockchain, putting roughly 6 to 7 million BTC at risk. Expert timelines range from under a decade to 40 years, and developers are already drafting quantum-resistant upgrades.
By The Pomp Podcast · Published October 24, 2026 · Last updated October 24, 2026
TL;DR
No quantum computer can steal bitcoin today. Google's March 2026 research estimates the job would take fewer than 500,000 physical qubits, far beyond any machine that exists.
The risk is to signatures, not to mining or the 21 million cap. Coins whose public keys are already on-chain are the ones exposed: about 6 to 7 million BTC by current estimates.
Timelines are disputed. Cryptographer Adam Back says "probably not for 20-40 years, if then." Google has set a 2029 target for its own post-quantum migration, and EU regulators warned in September 2026 that the threat could arrive early.
Fixes are in progress but not live. BIP-360 and BIP-361 are draft proposals. Neither has been activated.
Jordi Visser's view on The Pomp Podcast: "I'm not worried." He calls quantum a hardware problem and says AI-powered hacking is the bigger risk today.
What you can do now: stop reusing addresses, move coins off addresses that have already sent funds, and ignore any "urgent quantum upgrade" message.
From The Pomp Podcast, hosted by Anthony Pompliano, with guest Jordi Visser, veteran macro investor and author of the VisserLabs Substack. Episode released October 24, 2026.
Is quantum computing a threat to bitcoin right now?
Not right now. Quantum computing is a real long-term risk to bitcoin, but no machine that exists today comes close to breaking it. Hardware wallet maker Trezor puts it plainly: "No quantum computer today is capable of stealing your bitcoin."
That question went mainstream this month after investor Chamath Palihapitiya said bitcoin "eventually gets hacked" and "goes to zero," according to Benzinga. On the October 24 episode of The Pomp Podcast, I asked Jordi Visser, a macro investor with more than 30 years of experience and the author of the VisserLabs Substack, whether investors should be worried. His answer was blunt: "I'm not worried."
Visser's argument is that two different risks are getting lumped together. The threat people are seeing right now is a software and cybersecurity problem: AI agents probing reused passwords, weak systems and banks. He pointed to recent Axios reporting on how AI has exposed hidden security weaknesses across the internet. That attack surface is the same one every company and every bank faces. It is not unique to bitcoin.
Quantum is a different category. In Visser's words, "quantum is a hardware issue." A machine powerful enough to break modern cryptography has to be built first.
How does bitcoin's cryptography work?
Bitcoin relies on two kinds of cryptography, and quantum computers threaten them very differently.
Digital signatures (ECDSA and Schnorr). These prove you own your coins. Both use elliptic curve cryptography on a curve called secp256k1. Your private key signs a transaction, and your public key lets the network check that signature. Today, working backward from a public key to its private key is effectively impossible.
Hash functions (SHA-256). These secure mining, link blocks together and, in most address types, hide your public key until you spend.
A quantum computer attacks each one with a different algorithm:
Shor's algorithm | Grover's algorithm | |
|---|---|---|
What it attacks | Elliptic curve signatures (ECDSA, Schnorr) | Hash functions (SHA-256) |
Speed-up | Exponential: turns an impossible problem into a solvable one | Quadratic: roughly halves the effective security |
Effect on bitcoin | Could derive private keys from exposed public keys and steal coins | Weakens but doesn't break hashing; quantum mining is impractical at scale |
How serious | The main quantum risk to bitcoin | Considered manageable |
The Chaincode Labs report on bitcoin and quantum computing explains why Grover isn't a mining threat: its speed-up can't be parallelized the way ASIC mining can. So the real question is about ownership of coins, not whether the network keeps running. As the Presidio Bitcoin quantum readiness report notes, a quantum computer would not stop blocks from being produced or change the 21 million supply cap.
Key terms
CRQC (cryptographically relevant quantum computer): a quantum computer large and reliable enough to break today's public-key cryptography.
Q-Day: shorthand for the day a CRQC first exists.
Physical vs logical qubits: physical qubits are the noisy hardware units. A logical qubit is an error-corrected qubit built from many physical ones. Breaking bitcoin requires logical qubits.
Exposed public key: a public key that is already visible on the blockchain, which a future CRQC could target.
Which bitcoin is vulnerable to quantum computers?
Only coins whose public keys are already visible on-chain are exposed while they sit still. Most modern addresses hide the public key behind a hash until the coins are spent. Coins are exposed in three main ways:
Early pay-to-public-key (P2PK) outputs. Many Satoshi-era coins were sent straight to a public key. Roughly 1.7 million BTC sits in these outputs, according to an ARK Invest and Unchained white paper published in March 2026. Much of it is believed to be lost, including coins attributed to Satoshi Nakamoto.
Reused addresses. Spending from an address reveals its public key. Any coins left at that address, or sent to it later, are exposed.
Taproot (P2TR) outputs. Taproot puts a tweaked public key directly in the address, so these outputs are exposed from creation.
Estimates of bitcoin whose public keys are already visible on-chain. Methods differ; sources are linked in the table below. Chart: pomppodcast.com.
Source | Exposed BTC | Share of supply | Date |
|---|---|---|---|
6.04 million | 30.2% | May 2026 | |
~6.5 million | ~1/3 | April 2026 report | |
~6.9 million (1.7M P2PK + 5.2M reused/Taproot) | ~35% | March 2026 | |
CryptoQuant, via CoinDesk | ~6.9 million | n/a | September 2026 |
7.12 million | 35.4% | Snapshot October 18, 2026 |
The estimates differ because analysts count differently, but they agree on scale. The bigger point is that most exposure comes from behavior, not design. Glassnode found 4.12 million BTC exposed through address reuse and custody practices, versus 1.92 million BTC exposed by script type. Exchange-related balances alone accounted for 1.63 million BTC, or 8.1% of all issued bitcoin. That exposure can shrink without any change to bitcoin's code.
How many qubits does it take to break bitcoin?
Far fewer than people thought a year ago, but still far more than exist. In March 2026, Google Quantum AI published resource estimates for breaking the 256-bit elliptic curve problem behind bitcoin's signatures:
fewer than 1,200 logical qubits and 90 million Toffoli gates, or fewer than 1,450 logical qubits and 70 million Toffoli gates;
runnable in minutes on a superconducting machine with fewer than 500,000 physical qubits;
about a 20-fold reduction in physical qubits versus earlier estimates.
The full paper also warns that fast quantum machines could enable "on-spend" attacks. That means grabbing a public key from a transaction waiting in the mempool and racing to spend the coins first. CoinDesk reported the paper's estimate of about nine minutes per key, giving an attacker a 41% chance of beating bitcoin's roughly 10-minute block time.
For context on today's hardware, IBM's roadmap targets IBM Quantum Starling, a fault-tolerant machine with 200 logical qubits, for delivery in 2029. That would be a milestone, but it is still well short of the more than 1,000 logical qubits in Google's estimate.
When will quantum computers break bitcoin?
No one knows, and serious people disagree by decades. Here's the range:
Who | What they've said |
|---|---|
Adam Back, cryptographer and Blockstream CEO | "Probably not for 20-40 years, if then," on X in November 2025. In April 2026 he said bitcoin should still prepare now and give holders about a decade to migrate. |
Google Quantum AI | Set a 2029 timeline for its own migration to post-quantum cryptography, saying cryptographically relevant quantum computers "are getting closer to reality." |
NIST | A draft transition plan (IR 8547) proposes deprecating today's 112-bit elliptic curve signatures after 2030 and disallowing them all after 2035 for U.S. federal systems. |
EU financial supervisors | Warned in September 2026 that quantum threats "could materialize earlier than any viable commercial application," per CoinDesk. |
Jordi Visser, on The Pomp Podcast | Relayed Back's 20-to-40-year view and noted others say 5 to 7 years. Either way, he expects the community to have time to respond. |
Visser told me he studied the quantum question in 2020, before making bitcoin a big part of his own net worth, and that he leans on Back for the technical view. Ask "when will quantum computers break bitcoin?" and the honest answer is this: the timeline is uncertain, the upgrade takes years, so the work has to start before the threat is proven.
Is bitcoin becoming quantum resistant?
The work has started, but nothing is live on bitcoin's main network yet.
NIST post-quantum standards. In August 2024, NIST finalized its first three post-quantum standards: ML-KEM (FIPS 203), ML-DSA (FIPS 204) and SLH-DSA (FIPS 205). The last two are signature schemes bitcoin could adopt.
BIP-360, Pay-to-Merkle-Root (P2MR). This draft soft-fork proposal was merged into the official BIPs repository in February 2026. It creates a Taproot-like output with the quantum-vulnerable key path removed, so no public key sits on-chain. The spec is clear that it does not add post-quantum signatures by itself. It is a draft, not an activated upgrade.
BIP-361, Post Quantum Migration and Legacy Signature Sunset. This draft proposal, co-authored by Jameson Lopp, lays out a phased plan. Sends to vulnerable address types would stop first. Spends using legacy signatures would be restricted later, with a proposed recovery path. It is the most controversial idea in the debate because coins that never migrate, including lost coins, could be frozen.
Migration capacity is less of a bottleneck than you might expect. The Presidio Bitcoin report estimates that with about 25% of block space dedicated to migration, around 90% of bitcoin's value could move in about four days. The hard part is agreement, not throughput.
Can the bitcoin community coordinate an upgrade in time?
This is the strongest version of the bear case. Palihapitiya argued that migrating to quantum-resistant cryptography is "basically impossible" given how divided the community is, according to Benzinga. The Presidio report reaches a related conclusion: coordination and speed, not technical feasibility, are the main risks.
Visser agrees the community has to come together. But he made a point every investor who has lived through a crisis will recognize: you know what speeds up crisis management? A crisis. Pressure forces decisions.
He also pointed to a new set of stakeholders. As banks and financial institutions move onto crypto rails, Visser argues, they gain a vested interest in keeping bitcoin secure. That brings more resources to the problem. You can already see it: on October 13, 2026, Coinbase, which says it holds about 12% of all BTC, published its considerations for bitcoin's post-quantum transition and said the work should begin now.
My view: security is always a cat-and-mouse game between good guys and bad guys, and the good guys tend to have far more money. Bitcoin is not going to zero. But quantum is a legitimate risk that should be taken seriously, not dismissed.
How can you protect your bitcoin from quantum computers?
You don't need to panic, and you don't need special software today. These five steps reduce your exposure now:
Stop reusing addresses. Use a fresh receive address for every payment, which most modern wallets do automatically. Google's researchers specifically recommend against exposing or reusing vulnerable wallet addresses.
Move coins off addresses that have already sent funds. If an address has spent before, its public key is public. Sending the remaining balance to a new, unused address puts the coins back behind a key that hasn't been revealed.
Ask your custodian about its plan. Glassnode's data shows exposure varies widely between exchanges and custodians. If someone else holds your keys, ask how they're preparing.
Ignore "urgent quantum upgrade" messages. Trezor says there are no Trezor Suite or firmware updates related to quantum computing, and that any email about urgent quantum-resistant upgrades should be treated as a scam. Never type your seed phrase into anything.
Watch for the real upgrade. If bitcoin activates a quantum-resistant output type such as BIP-360, protecting your coins should mean a wallet update and a move to a new address. Follow BIP-360, BIP-361 and your wallet maker's announcements.
And don't forget the risk Visser says is here today: AI-driven hacking. Unique passwords and strong account security on every exchange and email account matter more right now than quantum.
For the full back-and-forth on Chamath's comments, read Jordi Visser responds to Chamath's "bitcoin going to zero" claim.
Key takeaways
Quantum computing is a long-term threat to bitcoin's signatures, not to mining or the supply cap, and no machine can break bitcoin today.
About 6 to 7 million BTC has public keys already exposed, mostly because of address reuse.
Google estimates a key-breaking machine needs fewer than 500,000 physical qubits; IBM targets 200 logical qubits in 2029.
Timelines range from Adam Back's 20 to 40 years to warnings that the threat could arrive sooner.
BIP-360 and BIP-361 are drafts, and NIST's post-quantum signature standards already exist.
Jordi Visser is "not worried" and calls quantum "a hardware issue," while I believe the risk deserves serious attention.
Best quotes from the episode
"So quantum is a hardware issue. I want everyone to hear that. Because we're going through this with AI right now."
"It's hardware. It's the physical world. That's where quantum's pain point is."
"But you know what speeds up crisis management? A crisis."
FAQ
Can quantum computers break bitcoin today?
No. Breaking bitcoin's signatures would take a fault-tolerant quantum computer with more than 1,000 logical qubits, according to Google's 2026 estimate. No such machine exists, and today's machines are far smaller and noisier.
How many qubits are needed to break bitcoin?
Google Quantum AI estimated in March 2026 that it would take fewer than 1,200 logical qubits, or fewer than 500,000 physical qubits on a superconducting machine, running for minutes. That is about 20 times fewer physical qubits than earlier estimates.
How much bitcoin is vulnerable to quantum computers?
Roughly 6 to 7 million BTC, or about 30 to 35% of supply, has a public key already visible on-chain. Glassnode puts it at 6.04 million BTC and ChainQuery at 7.12 million. About 1.7 million BTC sits in early P2PK outputs.
When will quantum computers break bitcoin?
No one knows. Adam Back has said "probably not for 20-40 years, if then," while EU regulators warned in 2026 that the threat could arrive sooner than expected. Google has set 2029 for its own post-quantum migration.
What is BIP-360, and does it make bitcoin quantum safe?
BIP-360 is a draft proposal for a new output type, Pay-to-Merkle-Root, that keeps public keys off the chain. It reduces long-term exposure but does not add post-quantum signatures, and it has not been activated.
Can quantum computers break SHA-256 or bitcoin mining?
Not in a meaningful way. Grover's algorithm only gives a quadratic speed-up against SHA-256, and it can't be parallelized like ASIC mining. The main quantum risk is to signatures and coin ownership.
What happens to Satoshi's bitcoin if quantum computers arrive?
Satoshi-era coins in P2PK outputs have exposed public keys and can't be migrated if the keys are lost. BIP-361 proposes eventually freezing unmigrated legacy coins, which is the most contested question in the debate.
How do I protect my bitcoin from quantum computers?
Avoid address reuse, move funds off addresses that have already spent, ask your custodian about its plan, ignore "quantum upgrade" scam emails and watch for an activated quantum-resistant address type.
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Watch or listen to the full episode
Visser walks through why he isn't worried about quantum computing yet, and why he sees AI-powered hacking as the nearer-term risk.
"Will Bitcoin Survive Quantum Computing?" with Jordi Visser, October 24, 2026. The quantum discussion starts around 1:01.
More from this episode
Sources
Google Quantum AI, resource estimates and blog post (March 31, 2026) and paper on arXiv
NIST, first three finalized post-quantum standards (August 2024) and IR 8547 draft transition plan
Glassnode, Measuring Bitcoin's Quantum-Exposed Supply (May 20, 2026)
Presidio Bitcoin, Bitcoin's Quantum Readiness (April 2026)
ChainQuery, Bitcoin Quantum Exposure (snapshot October 18, 2026)
Chaincode Labs, Bitcoin and Quantum Computing
ARK Invest and Unchained, Bitcoin and Quantum Computing (March 2026)
Coinbase, Working Together on Bitcoin's Post-Quantum Readiness (October 13, 2026)
IBM, Quantum Starling announcement (June 10, 2025)
CoinDesk on the EU supervisors' warning, Google's paper and Adam Back
Anthony Pompliano is an entrepreneur, investor, and author who serves as Chairman and CEO of Silvia, Inc (SVIA) and invests through Pomp Investments. He is the host of The Pomp Podcast, where he interviews founders, investors and economists about bitcoin, markets, AI and the economy. This article is based on his October 24, 2026 conversation with Jordi Visser, with outside facts checked against the sources listed above. Follow Pomp on X (https://x.com/APompliano).
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This article reflects the opinions of the guest and host as shared on The Pomp Podcast, plus outside sources linked above. It is not investment advice. Do your own research before making any investment decision.
