The Quantum Era Is Near—Are You Ready?
Alex and Conor of Project 11 on safeguarding blockchains before it’s too late
In this week’s episode, I spoke with Alex Pruden and Conor Deegan from Project Eleven. We returned to a topic we had covered earlier this year, that is quantum computers. But instead of looking at how quantum computing works, or where quantum and cryptography overlap, in this episode we focused on the threat that state-of-the-art quantum computers pose to today’s cryptographic systems — specifically to the signature schemes used in blockchains.
Early on in the conversation, Alex made the point that as blockchain technology becomes a foundational layer of global financial systems, for example with stablecoins being incorporated into banking rails, the risks presented by quantum computers become far more serious. If blockchains were to remain just an exotic asset used by a few, then while quantum computers could damage the users of those networks, the larger economic systems might be spared. But as these technologies get closer to the heart of financial infrastructure, we need to be much more concerned about the impact of quantum and plan for mitigation strategies.
This is what Alex and Conor are working on with Project Eleven, and what we spent most of the episode discussing. As they explained, the most complicated part of this process is not how to upgrade blockchains to be post-quantum secure, but how to get users to start protecting their funds individually — since in self-sovereign systems the blockchain developers won’t be able to “upgrade” each address for the users. The users will need to do this themselves.
Put another way: other cryptographic systems, like browser security or chat encryption, are built on centralised systems that can easily deploy upgrades behind the scenes. But in the case of blockchains, funds are held on accounts accessible by signature schemes that are at risk. These accounts are fully controlled by end-users. So a simple software update won’t cut it.
Key takeaways from Episode 383
Quantum computers are moving from theory toward reality — recent progress has accelerated faster than most researchers in quantum had predicted.
The most immediate threat is Shor’s algorithm, which can reverse public keys into private keys, effectively breaking Elliptic-Curve-Cryptography cryptography and by extension the signature schemes underpinning major blockchains like Bitcoin and Ethereum.
Grover’s algorithm, which affects hashes and symmetric cryptography (and by extension, some PoW-based problems), is also a potential risk for quantum computers, but is farther off.
I learned about the term Q-Day (the moment a quantum machine becomes cryptographically relevant).
Blockchains are especially vulnerable because users hold their own keys,upgrading the network alone doesn’t protect existing funds. Each user may eventually need to migrate their assets to post-quantum wallets, a process that could take years and introduces major UX and security risks.
Project Eleven is focused on solving this migration challenge through a layered approach:
Implementing customized post-quantum signature schemes optimized for blockchain performance within the protocols.
Building a vault system that lets users secure assets with post-quantum cryptography before full network upgrades.
Developing a global namespace, similar to DNS, to map pre-quantum and post-quantum addresses, improving UX while enabling large-scale migration.
Alex and Conor emphasise that action must happen before a cryptographically relevant quantum computer appears. Once Q-Day arrives, migrating safely becomes far harder, since the act of migration may reveal the address in the mempool and draw attacker attention.
Some newer networks (e.g., Sui) are already exploring hybrid solutions using zero-knowledge proofs and hash-based cryptography as potential mitigations. But they will still need end-users to participate in mitigation.
The conversation also highlighted how post-quantum thinking connects to zero-knowledge (ZK) research, with hash-based and lattice-based SNARKs being inherently more resilient to quantum attacks.
For me, this episode was a bit of a wake-up call. While we’ve discussed these problems before, they always felt distant. After this conversation, I’m left feeling it’s closer than we think!
Be sure to check out Episode 383: the full episode page is here, or follow this thread for commentary.
Talk soon,
Anna
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