Quantum Upgrades Could Make Blockchains More Attractive to Financial Institutions

Quantum computing could push financial institutions to consider blockchain infrastructure as they upgrade legacy systems threatened by attacks on today’s public-key cryptography, while Ethereum targets full post-quantum resistance by December 2029.

The technology threatens cryptography used for digital signatures, authentication and encryption across blockchains, banks, governments and internet services. Chris Perkins, Franklin Templeton’s crypto chief, argues that the risk does not mean digital assets will disappear.

“While the threat is real, the conclusion—that quantum will kill crypto—is simply wrong,” Perkins wrote Sept. 25.

Three post-quantum cryptography standards are ready for implementation, and migration should begin before quantum computers can threaten current encryption. Replacing cryptographic algorithms in information systems has historically taken 10 to 20 years, creating a long lead time for organizations that need to protect sensitive data.

The U.S. government aims to mitigate quantum risk as much as feasible by 2035. The threat also includes “harvest now, decrypt later” attacks, in which encrypted data is collected today for potential decryption by future quantum computers.

The date of a computer capable of breaking current cryptography remains uncertain. Estimates range from potentially by 2030 to more than 30 years, leaving institutions to prepare without a fixed deadline.

Ethereum’s roadmap

Public blockchains can replace cryptographic components through protocol upgrades, but those changes require coordination among developers, validators, users and infrastructure providers. Ethereum’s documented roadmap targets full post-quantum resistance across the network’s execution, consensus and data layers by December 2029.

That date is a roadmap milestone, not evidence that Ethereum is already quantum-safe or that the upgrade is complete. The practical question is whether a network can coordinate the required changes before quantum systems pose a credible threat.

The risk has also drawn attention from European financial supervisors, who have warned that quantum computing could eventually weaken the cryptography securing blockchain systems. Earlier coverage of European regulators’ quantum warning examined the potential threat to communications, transactions, databases and blockchains.

A long modernization cycle

Traditional financial infrastructure is undergoing its own multiyear changes. The Fedwire Funds Service completed its migration to the ISO 20022 messaging format on July 15, 2025, and settles more than $4.7 trillion in wire transfers on an average day.

The Bank of England’s new real-time gross settlement core ledger and settlement engine went live April 28, 2025, after a multiyear renewal program. The system settles more than £800 billion on an average working day. A 2016 announcement had set a provisional completion target of 2020 for the next-generation service.

Those projects modernized payment messaging and settlement infrastructure but did not directly replace the underlying cryptographic systems. In October 2025, nine firms also took part in a four-week challenge examining how wholesale central bank money could be transacted and settled on an external programmable ledger.

The comparison suggests that large financial systems can take years to modernize, but it does not establish that crypto networks are already ahead in quantum readiness. The broader case is that quantum computing may reshape how trust is distributed across digital assets rather than eliminate them.

For blockchain networks, the next concrete benchmark is Ethereum’s December 2029 target for full post-quantum resistance across its execution, consensus and data layers.