After diving into the science of quantum computing in the second episode, the Entrust Engage podcast moves toward the world of blockchain and the impact of quantum computing on it in the third episode. Providing commentary on this topic was Jon Geater, Chief Product and Technology Officer at RKVST, and Pali Surdhar, Director of Product Security at Entrust. The intersection of blockchain and quantum computing is quite fascinating, and that’s exactly what this episode explores. Here are the four key things I learned from this conversation:

#1: What is blockchain?

Before we go further into how quantum computing impacts blockchain, it’s important to have a foundational understanding of just what this technology is. As this episode explains, blockchain is ledger-based, decentralized, and built on high-integrity cryptography. It features two crucial properties: Control is spread around to a number of participants, and accountability is shared and decentralized. Built on the foundation of cryptography and fair-access principles, blockchain ensures fair access, good control, and knowledge of trustworthiness of the data.

#2: Is blockchain at risk from quantum computing?

In blockchain, the threat from quantum computing has more to do with the integrity of historic ledger records than the decryption of data. If a bad actor was able to back-date data and effectively rewrite history by leveraging quantum computing, it would break the blockchain principle of ensuring the truthfulness of data.

While this could be a potential vulnerability in the future, at present blockchain happens to be partially quantum-resistant already. Even if the technology were to be compromised, it could only happen at one point in time, in one place, on one computer, and in one piece of memory. And then after that, the computer must convince the other participants in the consensus that this is the correct version of history to accept. In a sense, the decentralized nature of blockchain networks has some built-in quantum resistance.

#3: In that case, does blockchain need to be prepared to mitigate risk?

There’s a significant overlap between what’s being required by regulatory bodies and the capabilities of blockchain-based architecture. Since there’s already some resistance in blockchain to quantum attacks, is there any urgency to transition to quantum-safe techniques? This can depend on the use case, but the answer is probably yes.

In blockchain, if the use case involves a confidentiality requirement, key exchanges are occurring, and there exists the same vulnerability as in the wider internet. Another important consideration is the data inside the blocks themselves; users need to make sure the chain references or digests can’t be faked. That’s another situation in which it is useful to have quantum-resistant algorithms deployed.

#4: When should blockchain prepare for the quantum threat?

To paraphrase our experts: Prepare now but know you’re not alone. Blockchain creates accountability for its shared infrastructure. Blockchain users would be wise to update their cryptography and transition their algorithms to quantum-safe options as outlined by NIST. They exist in a community; the best advice is for users to come to a consensus about protecting assets and joint histories for the road ahead.

To hear all about the intersection of blockchain and quantum computing, have a listen to the third episode of Entrust Engage. For more information on post-quantum cryptography and how to prepare, check out our Post-Quantum Preparedness webpage.