Bitcoin vs. Quantum Computing: More Hype Than Reality 

This is the first article in the Common Bitcoin Myths and Misconceptions Debunked series.

Quantum computing often raises concerns about Bitcoin’s future, with some fearing that these powerful machines could one day compromise its security. While the concern is understandable, a closer look reveals that quantum computing is far from posing any immediate threat to Bitcoin. Here’s why bitcoin investors, holders, and the like can remain confident.

Bitcoin’s Cryptographic Foundations

Bitcoin’s security relies on two main cryptographic tools:

1. ECDSA (Elliptic Curve Digital Signature Algorithm): Protects private keys and authorizes transactions.

2. SHA-256: Ensures data integrity, obfuscates addresses, and powers Bitcoin’s Proof-of-Work mining.

Quantum computing’s theoretical threat to Bitcoin lies in the possibility of breaking these cryptographic tools. Specifically, the two algorithms most often cited are:

• Shor’s Algorithm, which an attacker could use to derive private keys from public keys.

• Grover’s Algorithm, which an attacker could use to reduce the computational effort required to reverse the SHA-256 hashing mechanism.

However, while these threats are theoretically possible, quantum computing is far from achieving the power needed to execute them.

How Far Are We from Quantum Computers That Could Threaten Bitcoin?

Current quantum computers are decades away from being able to break Bitcoin’s encryption.

To break ECDSA within an hour would require approximately 317 million physical qubits. Today’s quantum computers have around 100 qubits. Even if the timeline were extended to five years, it would still take around 6,000 qubits to crack ECDSA.

Similarly, while Grover’s Algorithm could theoretically reduce the effort needed to crack SHA-256 from 2^256 operations to 2^128, this still represents an astronomically large number of computations.

For context, Google’s latest quantum processor, Willow, has just 105 qubits. According to physicist Sabine Hossenfelder, practical applications of quantum computing are "about 1 million qubits away" and remain decades from reality. When it comes to breaking cryptographic code, the requirement jumps to 13 million qubits or more.

Based on Moore’s Law, it’ll likely be at least a decade or longer before quantum computers threaten Bitcoin in its current state.

See the graphic below for an illustration of the possible timelines for quantum advancement according to Moore’s Law.

Quantum Hype vs. Reality

Even Google’s much-hyped claims of “quantum supremacy” have faced skepticism. IBM has pointed out that the same calculations could be achieved using classical supercomputers in reasonable timeframes.

Kevin Rose, a former senior product manager at Google, noted that while Willow’s 105 qubits represent progress, it’s a far cry from the 13 million qubits needed to break Bitcoin’s encryption.

Why Bitcoin Is Resilient to Quantum Advances

Bitcoin’s design gives it built-in advantages against attacks:

• Difficulty Adjustment: Bitcoin’s Proof-of-Work system adjusts mining difficulty every 2,016 blocks to maintain a consistent block time of ~10 minutes. If a quantum computer were to mine blocks faster, the network would adapt, preventing unfair advantages.

• Public Key Security: Public keys are only revealed when you spend coins. The best practice is never to reuse addresses to keep funds secure, even against quantum threats.

• Hash-Obfuscated Addresses: Addresses based on hashed public keys (p2pkh) add another layer of protection, making it more difficult for attackers to exploit quantum weaknesses.

These features mean that even if quantum computers could break all of Bitcoin’s encryption tomorrow, not every wallet would be vulnerable. In addition, the network can react to emerging threats in real time.

Preparing for the Future: Bitcoin’s Ability to Adapt

If quantum computing does eventually threaten current cryptography, Bitcoin has options:

• Upgrades: As Satoshi Nakamoto suggested in 2010, the network could transition to more quantum-resistant algorithms should the need arise. For example, Bitcoin could upgrade from SHA-256 to SHA-512. Depending on how imminent the threat seems, the network could adapt in one of two ways:

• Community-Driven Solutions: Bitcoin’s decentralized governance allows for swift, collective decisions. Developers are already working on solutions. For instance, a soft fork proposal called QuBit by Bitcoin developer Hunter Beast (@cryptoquick) introduces post-quantum public keys.

As Satoshi stated, SHA-256 is much stronger than most other cryptographic algorithms, meaning that quantum computers pose an even bigger risk to other critical web infrastructures.

Quantum Threats Aren’t Just a Bitcoin Problem

Quantum computing doesn’t only challenge Bitcoin—it threatens all cryptographic systems, including:

• Banking security

• Secure communications

• Internet encryption as a whole

This shared risk is driving global research into post-quantum cryptography. The world is aware of the potential threat and is actively developing solutions.

Bitcoin is uniquely positioned to implement a solution due to its decentralized nature and built-in incentive structure. If a new threat emerged that could weaken the security of the trillions of dollars stored in the network, users would respond swiftly, pouring energy and resources into strengthening the network. By contrast, re-building and re-starting a global bank’s infrastructure, for example, could take much longer than executing a soft fork in the Bitcoin code.

The Bottom Line: Bitcoin Is Built to Evolve

Quantum computing remains in its infancy, with the technology needed to challenge Bitcoin’s security likely decades away. In the meantime, Bitcoin’s adaptability, strong cryptographic foundation, and decentralized governance position it to meet any challenges head-on.

Quantum FUD (fear, uncertainty, and doubt) shouldn’t overshadow Bitcoin’s resilience and potential. While quantum computing advances, so will Bitcoin’s ability to evolve and remain secure.