(Nature) Within a decade, quantum computers will be able to break a blockchain’s cryptographic codes. This article highlights how quantum technology makes blockchains vulnerable — and how it could render them more secure.
Vulnerabilities: A wrongdoer equipped with a quantum computer could use Shor’s algorithm to forge any digital signature, impersonate that user and appropriate their digital assets. If nothing is done to update the protocols, cryptocurrencies will crash once quantum computers become available.
Improving Security: Fortunately, quantum technologies also offer opportunities to enhance the security and performance of blockchains. Quantum communications are inherently authenticated — no user can impersonate another. Such technologies use states of individual particles of light (photons) to encode bits and communicate them. Fundamental physics stipulates that quantum states cannot be copied or measured without being altered. Any eavesdropper will be immediately uncovered.
Next Steps:The blockchain business needs to update its existing software to use one-way cryptographic functions that are equally hard to reverse using conventional or quantum computers9.