The Cambridge Centre for Alternative Finance (CCAF), Cambridge Judge Business School, has shared insights from Wenbin Wu, Research Associate at the CCAF. Wu noted that the need to upgrade to a post-quantum environment is “more urgent for blockchains than for almost any other digital system.” They added that this is because of what is often called a ‘Harvest Now, Crack Later’ attack.
He further stated that in traditional finance, much of the data has “a limited shelf life.”
Meanwhile, blockchain transactions are mostly “public and permanent.”
Wu explained that this allows adversaries to “copy public keys from the blockchain today, and simply wait for a quantum computer powerful enough to derive the private keys in the future.”
Wu added that for blockchains, these types of vulnerabilities “are permanent risks, making the switch to quantum-resistant security an immediate and critical priority.”
He pointed out that industry professionals face a choice: act now or risk the integrity of blockchain-based markets and digital currencies.
Wu also touched on regulators’ and policymakers’ bridging roles “for quantum-resilient blockchains, and the importance of collaboration by technologists, economists, and regulators in the quantum age of financial technology.”
Blockchain systems now “underpin trillions of dollars in digital assets and financial transactions.”
According to Wu, quantum computing threatens the “cryptographic foundations of these networks.” He added that the “threat is not here yet, but quantum hardware and algorithms are progressing far faster than most anticipated.”
Quantum machines now have “over a thousand qubits, with much improved gate fidelities and error correction.”
Wu further stated that preparing blockchain ecosystems “for post-quantum cryptography (PQC) requires carefully coordinated upgrades in protocols, software, and governance.”
This work must happen now, “not when quantum computers are already breaking keys.”
The window for a smooth transition is “rapidly narrowing.”
He continued:
“The need to upgrade is more urgent for blockchains than for almost any other digital system, because of what is often called a ‘Harvest Now, Crack Later’ attack. In traditional finance, much of the data has a limited shelf life. In contrast, blockchain transactions are public and permanent. This allows an adversary to copy public keys from the blockchain today and simply wait for a quantum computer powerful enough to derive the private keys in the future. For blockchains, today’s vulnerabilities are permanent risks, making the switch to quantum-resistant security an immediate and critical priority.”
The need to upgrade is more “urgent for blockchains than for almost any other digital system.”