Quantum Risk to Crypto: Why Europol Says Exposed Keys Matter

Europol, the European Union’s police agency, published findings on quantum computers and crypto on October 7, 2026. According to reporting by CoinDesk and Decrypt, its main point was that the real risk is not blockchains like Bitcoin breaking. The risk is wallet keys that are already visible in public, which a powerful enough quantum computer could one day exploit.

That difference matters for anyone holding coins. A scary headline about “quantum breaking Bitcoin” pushes people toward either panic or dismissal. Europol’s framing, as reported, points to something more useful: you can check whether your own keys are exposed, for free, in about two minutes, without typing anything secret. The Bullrunners video, hosted by George Lee, walks through the threat, which coins are most exposed, and how two projects have prepared.

What is the quantum risk to crypto wallets?

The quantum risk to crypto wallets is that a powerful quantum computer could, in theory, work out a private key from a public key. Every wallet has two keys. The private key is the secret that lets you spend. The public key can be seen by anyone and proves a payment really came from you.

The math linking the two is easy in one direction and, for today’s computers, practically impossible in the other. A quantum machine that is powerful enough could run that math backwards. Give it a public key and it could derive the private key. That is the whole fear.

What headlines often leave out is that your public key is not always on show. On Bitcoin, many addresses only display a scrambled fingerprint of the key, called a hash, until you spend from them. As the video stresses, nobody has shown in public that a machine capable of this attack exists.

What did Europol actually warn about?

Europol warned that crypto wallets with exposed keys are the primary quantum risk, according to the coverage cited in the video. Decrypt’s headline put it more bluntly, naming crypto wallets as the main concern. Europol also urged a gradual move to post-quantum security, meaning systems designed to stand up to quantum machines.

The coverage also pointed to an idea called harvest now, decrypt later. The video plays an IBM explainer describing it: an attacker copies encrypted data today, holds onto it, and waits until a quantum computer can read it.

With crypto, the video notes, it is even simpler. Nothing has to be stolen, because a blockchain is public by design. Anyone can copy every exposed public key, store the list, and wait. If a capable machine ever arrives, that list becomes a target list. That is why, according to reports, Europol said waiting for a firm date before acting would be a mistake.

Can quantum computers break Bitcoin itself?

Quantum computers are not expected to break the Bitcoin blockchain as a record, according to the sources the video cites. Bitcoin’s security does two separate jobs: signatures, which prove you own your coins, and mining, which keeps the record in order.

The video quotes Coin Bureau, from December 2025, explaining that mining relies on hashing, where quantum computers offer only a limited theoretical boost. Costs and overhead make meaningful speed-ups unlikely, and even a quantum edge for big miners would mostly shift who wins blocks rather than collapse Bitcoin’s security model. The weak point is signatures on coins whose keys are already public.

Bitcoin developers are also working on it. A proposal known as BIP 360 would add a new type of address built with quantum attacks in mind. The video is clear that it is a proposal, not a finished upgrade, and any change like this needs wallets, exchanges, miners and users to move together.

On March 31, 2026, a paper from Google’s quantum team suggested that attacking the math behind Bitcoin signatures might take fewer resources than earlier estimates. Swan Bitcoin responded the same day by calling the paper a “warning flare”: a signal to prepare early, clean up exposed risks and improve wallet standards, not a sign that Bitcoin is finished. Bullrunners has also looked at how Google’s report named Algorand.

Which coins and addresses are exposed?

The most exposed coins are those whose public key is already visible on chain. Citing Coin Bureau, the video lists three groups on Bitcoin:

1. Early coins from Bitcoin’s first years, many stored in an old format that shows the public key openly.
2. Reused addresses: if you sent coins out of an address and left a balance in it, that address’s key is on the chain.
3. Taproot addresses, which start with bc1p and carry a version of the public key from day one.

How much Bitcoin sits in exposed addresses depends on who is counting and what they count. Some estimates run into the millions of coins, while others say only a much smaller amount looks like a realistic early target. The video advises caution with anyone quoting a single scary number as settled.

For altcoin holders, the picture is different. On many account-based chains, people reuse the same address, and the public key appears the first time they send anything. On some chains, including Algorand, the address is the public key. So for many altcoins, exposure is the normal state. The video’s point is not to panic, but to pay attention to how each project plans to move holders to safer accounts. XRP holders can read Bullrunners’ separate look at XRP and quantum signature risk.

How are Algorand and Zcash preparing?

Algorand and Zcash are the two projects the video highlights as planning early, with different approaches and unfinished work in both cases.

Algorand. Founder Silvio Micali, a Turing Award winner, pushed for quantum safety early. In a June 2026 clip from Algorand’s channel, Professor Chris Peikert says one of his first major tasks at Algorand was building state proofs as post-quantum attestations. Those use a signature scheme called Falcon, which NIST, the US standards agency, chose as one of its post-quantum schemes. Algorand has used Falcon for state proofs since 2022. With an August 2026 upgrade, regular users could open Falcon accounts on the main network, with support in Pera wallet. The catch: ordinary Algorand accounts still use the older signatures, so holders have to move into the new accounts. The project’s stated target is to be broadly quantum resilient before the end of 2027.

Zcash. Zcash is built around privacy, and its shielded pool hides who paid whom and how much. For privacy, harvest now, decrypt later is the worst version of the threat, because once old private payments are exposed they cannot be hidden again. CoinDesk’s research team argued in July 2026 that these attacks do not work well against Zcash because the keys needed to decrypt shielded transactions are not stored on the blockchain. The video presents that as CoinDesk’s analysis, not a guarantee. On July 28, 2026, Zcash switched on its Ironwood upgrade, which created a new shielded pool after concerns about a possible counterfeiting bug in the older Orchard pool. It also introduced quantum recoverable notes, a safety net meant to let owners recover funds if the underlying math is broken. CoinDesk reported in May 2026 that Zcash aims to be quantum proof by 2027. But Zcash also has transparent addresses that work much like Bitcoin’s, and no one has tested the recovery route in a real emergency.

Project	Approach described in the video	What is still open
Bitcoin	BIP 360 proposal for a quantum-resistant address type	Only a proposal; needs wallets, exchanges, miners and users to adopt it
Algorand	Falcon signatures for state proofs since 2022; Falcon accounts from August 2026	Ordinary accounts must move; target is end of 2027
Zcash	Ironwood upgrade with quantum recoverable notes, July 2026	Transparent addresses still exposed; recovery untested; target is 2027

The video also cautions against treating early preparation as a reason to switch coins. Algorand has worked with Falcon since 2022, and that did not protect holders from large price falls. Bitcoin has more developers, money and pressure behind it than almost any other chain. Smaller projects such as the Quantum Resistant Ledger, built around quantum safety since its 2018 launch, are tiny by comparison and carry their own risks.

The free 2-minute exposure check

This check never requires your seed phrase or private key. Never type either into any website.

1. Open your Bitcoin wallet and copy one of your receiving addresses, the public address you would give someone to pay you.
2. Paste that address into a public block explorer, such as mempool.space.
3. Look at whether the address has ever sent coins out. If it has, any balance still in it is exposed.
4. Check how the address starts. If it begins with bc1p, it is a Taproot address and its key is exposed by design.
5. If something shows up, do not rush. No machine capable of this attack has been shown in public.
6. Build the habit of receiving into a fresh address every time. Most modern wallets do this automatically.

If you are unsure what a seed phrase is or how to store one, see Bullrunners’ guide on what a seed phrase is and how to store it safely.

What to watch next

Watch for your wallet provider to announce quantum-safe address options, and follow BIP 360’s progress on Bitcoin. If your wallet offers a migration, use only its official app and its own instructions. The video warns that the first people to profit from quantum fear will not be quantum computers but scammers selling fake “quantum-safe upgrades” through links sent by strangers.

For Algorand and Zcash holders, the dates to track are the projects’ own 2027 targets, and whether holders actually move into the new protected accounts and pools. For everyone, the lasting lesson from Europol’s findings, as reported, is simple: the chain keeps its record, and the weak spot is any key already sitting in public.