Will Quantum Computers Break Bitcoin? (Expert Insights in 2025)

Since its creation, the possibility of bypassing Bitcoin's security has remained low. That is, until the emergence of quantum computers.

Unlike classical computers, quantum computers process data at unreal speeds, allowing them to solve complex problems millions of times faster than any other computer. These problems include the cryptographic algorithms that keep Bitcoin safe.

This raises the big question: Will quantum computers break Bitcoin? Read on to discover quantum computing and how it impacts the Bitcoin network.

Key Takeaways

• Quantum computers are super-fast machines capable of solving complex mathematical problems in a short amount of time.
• In theory, quantum computers could break Bitcoin, but they are not at that level yet and will not be for a while.
• To reduce the risks of quantum threats in the future, Bitcoin developers must find ways to make it quantum-resistant.

Understanding Quantum Computing

Quantum computing is a technological advancement in how computers process information. Quantum computers use quantum mechanics to interpret data uniquely so it can solve problems faster.

Recent quantum computers like Willow can solve problems that would take the average computer millions of years to solve, and now it can solve them in minutes.

Classical computers represent data in strings of 0s and 1s. This limits the amount of data they can process, making them slow at solving complex problems.

On the other hand, quantum computers use quantum bits or qubits to represent data. Properties like superposition and entanglement allow quantum bits to exist in several states simultaneously. This lets quantum computers handle a lot of data and solve complex math problems quickly.

This quality makes quantum computing a potential threat to Bitcoin.

Quantum Threats To The Bitcoin Network

Complex mathematical problems like Shor's algorithm and Grover's algorithm pose a problem to Bitcoin's security. It has not been a problem because conventional computers cannot use them. But quantum computers can.

In theory, advanced quantum computers using these algorithms could threaten Bitcoin's safety. Here are a few ways they could do so:

Bitcoin Wallets

Bitcoin wallets allow users to manage and create Bitcoin addresses. They work by generating private-public key pairs. The private key is created randomly. The public key comes from a mathematical operation using the private key.

Decrypting a public key is difficult because it is complex to factor in large numbers. However, quantum computing makes it possible.

Bitcoin wallets may face quantum attacks that expose private keys from public keys. This is because quantum computers using Shor's algorithm can easily break the encryption.

Even if the public key isn't exposed, there is still a risk of quantum threats. This is because quantum computers using Grover's algorithm can mimic Bitcoin's key-generation process. This allows them to generate private keys and exploit Bitcoin wallets easily.

Bitcoin Mining

Bitcoin mining uses SHA-256 to create and check new blocks. It takes roughly ten minutes to do so. Quantum computers using Grover's algorithm could likely do so in less time, creating a monopoly on the network.

However, it is unlikely that quantum computing will threaten Bitcoin mining. Quantum computers aren't produced on a large enough scale yet. This makes it hard to compete with the current network of miners.

Network Consensus

As with all blockchain networks, Bitcoin relies on its nodes to make decisions. As long as the nodes remain honest, the integrity of the system will not be compromised.

However, Sybil attacks threaten a network's decision-making ability. They occur when the number of fake nodes in a network outnumbers the honest ones. This affects transactions, communication, and decision-making in the network.

In theory, quantum computers could enhance the effectiveness of Sybil attacks. Quantum-enabled Sybil attacks can cause several issues.

For example, they could make honest nodes unable to authorize transactions. They could also change the transaction history or add fake transactions to the blockchain.

"It's key for us to keep up with cryptography and quantum computing. At this moment in time, the resources and scale are not there and will not be for some years. Developers are already broaching the subject of quantum-resistant algorithms. SHA-256 is used in many encryption methods, not just Bitcoin," said Daniel Keller, CEO of Flux.

"The standard will evolve over time to keep up with future threats. These include combining SHA-256 with other cryptographic techniques to enhance security, for example, using it alongside elliptic curve cryptography for digital signatures. There are plenty of ways to enhance security and performance optimization for the algorithm."

How To Manage A Quantum Attack on Bitcoin

To stop a quantum attack on Bitcoin, developers need to build quantum-resistant systems. The area of Bitcoin most likely to face an attack now and in the future is Bitcoin wallets.

Wallet migration to a less vulnerable address type or an update to the signature algorithm solves this issue.

"Quantum computing is an exciting field with significant potential, but its impact on Bitcoin is often misunderstood. While it’s true that quantum computers could theoretically threaten current cryptographic systems like those used in Bitcoin, we are still far from having quantum machines capable of such tasks," said Ben Charbit, Co Founder & CEO, Darewise

"Bitcoin’s decentralized and adaptable nature means that it can upgrade to quantum-resistant algorithms if necessary, and researchers have been preparing for this scenario for years. The same quantum risks apply to the entire global financial system, including banks and online security—not just Bitcoin."

When Will Quantum Computing Threaten Bitcoin Security?

It's hard to give an estimate regarding when quantum computing will be able to break Bitcoin. Today, the strongest quantum computers have 100 to 1000 qubits. This amount isn't enough to break the network.

It's safe to say that it will be years before quantum computing becomes a potential threat to Bitcoin. Still, Bitcoin developers must create quantum algorithms to reduce any potential threat from powerful quantum computers.

"Even if quantum computers become a reality soon, there is still a long way to go before they can be used commercially—and thus be exploited by attackers to crack Bitcoin private keys. If the Bitcoin community can act quickly, most users can successfully migrate before that date," Dr. Ren Zhang, Senior Researcher @ Cryptape and Nervos.

"If the migration fails due to ineffective decision-making, or if some users do not migrate before the deadline arrives, then adversaries with access to quantum computers will immediately calculate the private keys of approximately 20% to 30% of the addresses. This is because the corresponding public keys of these addresses have already been made public, they will lose protection against quantum computers."

FAQs

What are Digital Signatures?

Digital signatures are a way to verify that a private key authorized a Bitcoin transaction or several Bitcoin transactions. They provide a way to verify the ownership of funds without revealing the private key itself.

How long would it take a quantum computer to mine Bitcoin?

It is still unclear how much quantum computing could affect mining. In theory, large quantum computers could mine Bitcoin in a shorter time than ordinary powerful computers. At the moment, though, no quantum computers can mine faster than traditional computers.

Which crypto is quantum proof?

At the moment, there are only nine record cryptocurrencies that are quantum resistant. Some of them include Cellframe, Abelian, Mochimo, Ilcoin, Nervos Network and Nexus.

Can quantum computing reduce Bitcoin’s energy consumption?

Yes. In theory, due to its efficiency, Quantum computing could reduce Bitcoin's energy consumption. This is possible since large quantum computers could speed up the process of mining Bitcoin, thereby consuming less energy.