A Shortened Version Of A Recent Article By The Bitcoin Way.
For over a decade, the media has made repeated attempts to cast Bitcoin as a risky or flawed system, frequently raising new “existential threats.” The latest in this long line is the supposed danger posed by quantum computing. While the concerns are not entirely unfounded, they are typically overstated and misunderstood. A more balanced view reveals that while quantum computing does pose some long-term risks, Bitcoin is far from helpless and is, in fact, likely better positioned than most systems to survive and adapt.
What Is Quantum Computing?
To understand the threat, one must first understand quantum computing itself. Traditional computers process data in binary—ones and zeros. Quantum computers, on the other hand, use “qubits,” which can be in a state of 1, 0, or both simultaneously, thanks to quantum properties like superposition and entanglement. This parallel processing allows quantum computers to explore massive numbers of potential outcomes all at once, making them exponentially faster at solving certain types of problems.
These computers are still in early development. They require precise control of qubits through lasers or electromagnetic fields and must be housed in ultra-cold, controlled environments. Despite their promise, even the most advanced quantum systems today operate at only a few hundred qubits. Breaking Bitcoin’s cryptography would require machines operating at a scale of millions of qubits—something we’re still decades away from achieving.
How Quantum Computing Could Theoretically Threaten Bitcoin
The core of the concern is that quantum computers could one day crack the cryptographic algorithms that protect Bitcoin. Bitcoin uses the Elliptic Curve Digital Signature Algorithm (ECDSA) to secure wallet private keys. A sufficiently powerful quantum computer running Shor’s Algorithm could theoretically reverse-engineer a public key to derive its corresponding private key—allowing access to the associated Bitcoin wallet.
However, such capabilities are not yet possible. Experts estimate that it would take millions of qubits to break ECDSA. Current quantum computers like Google’s “Willow” chip operate at just over 100 qubits. In short, quantum computers are not yet a credible threat to Bitcoin wallets, but may become so in the next 10 to 20 years.
Bitcoin Is Not the Primary Target
Even if quantum computers were advanced enough to break ECDSA, it’s unlikely they would be deployed first against Bitcoin. Digital signature algorithms are used broadly across global infrastructure—including banking systems, corporate data centers, government agencies, and military communications.
If a quantum adversary had such a capability, their priorities would likely be nuclear codes, central banks, or critical national security targets—not individual Bitcoin wallets. Furthermore, any actor in possession of a working quantum computer would be incentivised to keep its existence secret to maintain strategic advantage, as the Allies did with Enigma in WWII.
The point is that the threat of quantum computing affects global cybersecurity, not just Bitcoin.
Bitcoin Is Not a Soft Target
Importantly, Bitcoin is highly adaptable. The protocol is open-source and supported by a global community of developers and users who are constantly refining and strengthening the system. Cybersecurity, in general, is an arms race—new threats emerge, and new defenses are developed.
Bitcoin has already demonstrated its ability to evolve. In its early years, Bitcoin used “pay to public key” (P2PK) addresses that directly exposed the public key. These were replaced with more secure “pay to public key hash” (P2PKH) addresses, which hide the public key until funds are spent. More recently, upgrades like SegWit and Taproot have provided additional privacy and efficiency improvements.
If and when quantum computing becomes a genuine threat, Bitcoin is likely to migrate to “post-quantum” algorithms, such as lattice-based cryptography. There are already several draft Bitcoin Improvement Proposals (BIPs) discussing such possibilities.
Bitcoin’s decentralised nature and open development process make it uniquely able to respond to technological challenges like quantum computing. Unlike centralised institutions, Bitcoin does not rely on slow bureaucratic processes to implement upgrades.
Steps Bitcoin Users Can Take Today
Although the quantum threat is not immediate, users can take simple steps now to reduce their exposure:
- Avoid Outdated Address Formats
Early address types like P2PK expose the public key, which would make them vulnerable if quantum computers emerge. Upgrading to modern formats like P2PKH, SegWit, and eventually post-quantum formats is essential. - Avoid Reusing Addresses
Even modern addresses reveal the public key when you spend from them. Reusing addresses after spending from them exposes the public key and reduces both privacy and security. Using a new address for each transaction is best practice. - Use High-Quality Wallets
Not all wallets follow best practice. Some wallets recycle addresses for change outputs, inadvertently reusing public keys. Others do not support modern address types or have not kept pace with protocol upgrades. Choose reputable wallets that follow best practices by default. - Segment Wallet Use by Purpose
- Cold storage: Use Native SegWit or future post-quantum address types that protect your public key until the point of spending.
- Spending wallets: Taproot addresses are useful for short-term use, as they obscure the public key during spending, enhancing transaction privacy.
- Understand UTXO Management
Users should educate themselves about how Bitcoin’s unspent transaction output (UTXO) model works. This becomes critical during high-fee periods, such as during mass migrations to post-quantum address types in the future. - Monitor Technological Developments
Staying informed about advancements in both Bitcoin and quantum computing will ensure that users can take pre-emptive steps before any threat becomes material.
When the Transition Comes
Eventually, Bitcoin will migrate to post-quantum cryptography. This transition may involve technical upgrades to the protocol, including changes to how digital signatures are generated and verified. When that happens, the network is likely to experience a rush of activity as users race to migrate their funds to more secure address types.
Those who have prepared in advance—by understanding address types, avoiding key exposure, and using proper tools—will navigate the transition with minimal disruption. Those who delay may face congestion, high transaction fees, and even permanent loss if their coins are left on vulnerable legacy addresses.
Final Thoughts
Quantum computing does represent a credible but distant threat to Bitcoin. However, it is a threat that affects the entire digital world—not just one cryptocurrency. In fact, because of Bitcoin’s open-source foundation, decentralised governance, and rapid adaptability, it may be better suited to confront the challenge of quantum computing than most other systems.
Users who take responsibility for their own security, follow best practices, and stay informed will be in the best position to protect their assets. Bitcoin, as a living technology, has already evolved through multiple stages and will continue to do so. The risk posed by quantum computing is real, but manageable—and certainly not existential.
The best way to be secure is not just to “HODL” your coins, but to invest in your knowledge and skills. In the world of Bitcoin, fortune favours the prepared.
Summary of a recent Article published by The Bitcoin Way