The European Union Agency for Law Enforcement Cooperation (Europol) published two reports on October 7 examining how quantum computing could affect cryptocurrencies and sensitive encrypted data, identifying the cryptographic keys that authorize transfers as the technology's most immediate point of attack on digital assets.

Wallet Keys Identified as the Main Point of Exposure

The agency's European Cybercrime Centre (EC3) report on quantum computing and cryptocurrencies singles out wallet keys as crypto's primary quantum vulnerability. According to the analysis, a sufficiently capable quantum computer could derive a private key from an exposed public key, potentially handing an attacker the authority needed to sign and broadcast a transaction.

The concern is best understood through the way wallets currently operate. A public address allows other parties to send assets to a wallet and verify its transactions, while the private key—or recovery phrase—gives the holder control over it. Today's computers cannot realistically work backward from public transaction information to obtain the private key required to sign a transfer. Europol's warning is that quantum computing could eventually change that calculation. The asymmetry is mathematical: Shor's algorithm, the quantum method mathematician Peter Shor first described in 1994, can in principle solve the problems underlying the elliptic curve signatures used by most major cryptocurrencies, given hardware of sufficient scale.

Europol also draws an important line between wallet signatures and the rest of a blockchain. Hash functions that protect important parts of blockchain integrity are comparatively more resistant to quantum attacks, the agency says. Its warning therefore centers on the systems that prove ownership and authorize transfers—precisely where a compromised key can immediately give someone control over assets. Europol is focused on who can approve a transfer, not on a sudden collapse of every blockchain record.

Upgrading Security Will Take Longer Than a Software Update

Quantum hardware capable of carrying out this type of attack has not yet reached the necessary scale, and Europol says the timeline remains uncertain. The agency nevertheless argues that there is little value in waiting for a precise date.

“Adapting systems and coordinating security upgrades will take time,” the agency wrote in its October 7 announcement.

The scale of the migration explains that urgency. Replacing a signature method affects far more than the underlying blockchain code, and a secure transition depends on developers, validators, wallet makers, exchanges, custodians and users moving in a compatible order:

• Developers need to select quantum-resistant signature methods and test them against existing software and security assumptions.
• Networks need validators, miners or node operators to run compatible code and agree on any required rule changes.
• Wallet providers and custodians need to support new keys, signing formats and migration tools.
• Users need clear instructions if funds eventually have to move to a new address or a different signing system.

Developers are not choosing in a vacuum: the US National Institute of Standards and Technology finalized its first post-quantum cryptography standards in August 2024, including the ML-DSA and SLH-DSA digital signature schemes, giving blockchain teams concrete algorithms to evaluate against the demands of live networks.

Europol calls this capacity “crypto-agility”—a safe route from an older security method to a stronger one that does not interrupt access to funds or leave holders behind. The process must be designed well before a threat becomes urgent, particularly on decentralized networks where no single company can force every participant to upgrade.

Today's Key Theft Already Shows Why Control Matters

Quantum computing would create a new route to wallet control, but the industry already confronts the same end result every day. Criminals use phishing, malware, impersonation, compromised platforms and physical coercion to obtain recovery phrases, private keys or access to accounts that can approve transfers.

Recent Chainalysis research estimated that $3.4 billion was stolen across crypto during 2025. The firm also identified roughly 158,000 individual wallet-compromise incidents affecting about 80,000 victims, involving an estimated $713 million in stolen value.

That research describes present-day theft rather than quantum attacks, but it gives Europol's warning practical context: private-key control already determines whether an attacker can move crypto assets. A future quantum-capable attack would seek the same authority through a weakness in public-key cryptography instead of a stolen seed phrase or a fraudulent support message.

Europol's warning therefore calls for long-term preparation while users and service providers continue to defend against the threats causing losses today. Quantum-resistant signatures would not eliminate phishing, exchange breaches, poor password practices or unsafe storage of recovery phrases.

The Second Report Looks Beyond Coins to Long-Lived Data

Wallet keys are only one part of the warning. Europol's second report, “Harvest Now, Decrypt Later,” turns to information that attackers can collect today and attempt to decrypt later, once more capable quantum computing becomes available.

The greatest concern involves information that must remain confidential for many years: government communications, intellectual property, medical records and identity data. An attacker does not need a quantum computer while collecting the material—only storage capacity, an expectation that the information will remain valuable and the ability to wait for better computing tools.

For crypto companies, this risk sits alongside the assets they hold. Exchanges, custodians and wallet providers can store identity documents, account details, support messages, internal communications and transaction-related records outside the blockchain. Europol says there is no clear evidence that this approach is being systematically used at scale, but it still recommends reviewing the encryption and key-management systems that protect long-lived data.

That creates two separate preparation jobs. Networks and wallet providers need an eventual route to stronger transaction signatures, while companies holding customer records must examine whether their data can remain confidential over the full period in which it has value.

Visible Preparation Without Panic

For users, the useful response begins with ordinary wallet security rather than a rushed move driven by a future threat. A legitimate network or wallet migration would arrive through official releases, documented software updates and clear instructions from the service a person already uses.

Unsolicited messages claiming that a wallet needs an immediate “quantum-safe” upgrade deserve caution, particularly when they request a recovery phrase, private key or connection to an unfamiliar application. Scammers routinely use technical language and urgency to create opportunities for theft, and quantum computing gives them another subject to exploit.

According to the agency, credible preparation looks like this:

• Networks: public research, testing a clear route for adopting stronger cryptography.
• Wallet providers and custodians: strong key protection today, plus a documented way to support future migrations.
• Users: established wallet software, offline recovery-phrase storage and careful verification of every upgrade request.

The clearest sign of progress will be practical work that users can inspect: published technical proposals, compatible wallet releases, independent reviews and migration guidance that does not demand blind trust. A promise that a product is “quantum-proof” offers far less value without those details.

Engineering Deadline Without a Date

No one can say when quantum computers will be able to threaten wallet cryptography at scale, and Europol's argument does not depend on predicting that date. It rests on the time required to agree on stronger standards, test them on live networks and move users safely to new signing systems.

Crypto's quantum challenge therefore begins with preparation rather than a sudden attack. Wallet keys sit at the center because they determine who can move assets, and building a credible way to protect that authority before quantum hardware becomes capable will matter far more than guessing the year when the threat first becomes real.

This article is for informational purposes only and does not constitute cybersecurity, financial or investment advice. Quantum-computing capabilities, security standards and wallet software may change as research develops.