EHNINGEN, GERMANY – OCTOBER 01: A model of IBM Quantum shows the three chandeliers that would be a part of the System Two installation, the System One comprises of one such chandelier, seen during the inauguration of Europe’s first IBM Quantum Data Center on October 01, 2024 in Ehningen, Germany. The center will provide cloud-based quantum computing for companies, research institutions and government agencies. (Photo by Thomas Niedermueller/Getty Images)
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Today marks the 17th anniversary of the Bitcoin white paper, a technical document that explains how this decentralized system works and what it offers to the world. Published to a privacy and cryptography mailing list by Bitcoin’s pseudonymous and mysterious creator, Satoshi Nakamoto, it stands as the foundational text of one of the most important technologies built in the 21st century. Despite its incredible growth and legitimacy, spoiled by recent developments in the U.S., we want to explore one of the main challenges Bitcoin could face in the coming years: quantum computing.
No regulatory framework, prohibition, or legal threat could have such an impact. Since Bitcoin is purely applied cryptography, it is crucial to understand how the rise of more powerful quantum computers could affect the system. Looking at the white paper and how the protocol functions, there are two key components that could be compromised: the proof-of-work algorithm based on SHA-256, and the mining process that depends on this hashing function. Both are critical and could be disrupted or even broken. Moreover, as transactions pass through the mempool before confirmation (exposing the public key), a sufficiently advanced quantum computer could potentially double-spend bitcoin from unconfirmed transactions.
However, let’s be clear: quantum computing is still far from posing a real threat to Bitcoin. Despite the sensationalism surrounding it, today’s machines are nowhere near capable of breaking Bitcoin’s cryptography. For instance, doing so would require between 2.5 and 25 million physical qubits, whereas Google’s state-of-the-art Willow chip integrates around 105 physical qubits. This means Willow remains four to six orders of magnitude below the required scale.
If quantum computing is not a real threat today, why does it matter? Because making Bitcoin fully quantum-resistant is not as straightforward as one might think.
Keep in mind that the bitcoins mined by Satoshi have visible public keys, making them the first practical targets. The same applies to other early P2PK outputs, meaning that over one million coins could be at risk as low-hanging-fruit targets. This large number of vulnerable coins could ignite a major debate between those who would prefer to let them be stolen and those who would rather protect them, even in the absence of their rightful owner. That brings us to the first problem: achieving consensus among users.
The Social Layer Problem in Making Bitcoin Quantum-Resistant
One of the key factors in protecting Bitcoin from a potential quantum threat lies in its users, the global Bitcoin community. The last two major protocol upgrades, SegWit and Taproot, required significant time and effort to reach consensus and were stressful processes for everyone involved and shows how difficult the process could be.
Currently, there is a draft proposal to introduce post-quantum cryptography into Bitcoin, authored by the pseudonymous developer Hunter Beast, to address quantum-vulnerable addresses. This is Bitcoin Improvement Proposal 360. The BIP introduces “pay-to-quantum-resistant-hash” address types, incorporating three new signature algorithms with quantum-resistant properties.
However, given that this practical mitigation path would require at least a soft fork — for example, to add post-quantum signature schemes such as Dilithium, Falcon, or SPHINCS+ — it is worth asking whether the global Bitcoin community is ready to begin this process and move forward. Especially considering that it could impact Bitcoin’s core value proposition. Optimistically, according to the author, it could take up to two years of discussion and consensus-building around the feasibility of this BIP.
Today is a day to celebrate the disruptive technology Bitcoin represents. But as Bitcoin continues to grow and become increasingly significant in the geopolitical landscape, it is essential for its community of users, developers, and investors to evaluate more deeply what the emergence of quantum computing could mean for its future.