Quantum Computing Poses a Big Threat to Bitcoin
There’s growing worry that quantum computers could shake up cryptocurrencies. Experts say that once these machines hit the mainstream, maybe within a decade they could break the math behind most of today’s encryption. Regular computers take a long time to solve certain problems that secure digital money. Quantum computers, in contrast, can tackle these problems much faster, which puts assets like Bitcoin at risk.
Testing Bitcoin Against Quantum Attacks
BTQ Technologies is trying to get ahead with a project called Bitcoin Quantum. It’s a public test network where miners, developers, and researchers can experiment with transactions that are resistant to quantum attacks. The network even has a mining pool and block explorer so people can see how the system works in practice.
Chris Tam, BTQ’s quantum innovation lead, said there are two main threats. A quantum computer could figure out a private key from a public key, or it could mess with the network’s proof-of-work system. Either way, security would take a serious hit.
“Bitcoin is built on the idea that a public key can’t be reversed into a private key,” Tam said. “Quantum computers change that. They make what we thought was hard, really easy.”
Post-Quantum Cryptography Is the Answer
The good news is there’s a way to defend against this. Post-quantum algorithms are already being developed. They use the same basic digital signatures Bitcoin uses now but rely on math that quantum computers can’t easily solve. One example is Dilithium, officially called the Module-Lattice-Based Digital Signature Algorithm. This was standardized in the U.S. in 2024 and is the core of Bitcoin Quantum.
The catch is that these algorithms are bigger and slower. Tam said they can be at least 200 times heavier than current digital signatures. That makes them more expensive and resource-intensive, especially for networks as large as Bitcoin.
Hard Forks Could Be a Tough Sell
Switching Bitcoin to post-quantum security would require a hard fork. That means older versions of the software wouldn’t be compatible, and the community tends to resist these big changes. Many fear it could create a new cryptocurrency, not the Bitcoin they know.
Proposals like BIP-360 try to introduce quantum-resistant addresses gradually, but there’s no set timeline. Adoption will likely be slow, as Bitcoin’s community is cautious about big moves.
Tam points out that Bitcoin’s creator, Satoshi Nakamoto, seemed aware of the quantum risk from early on. Changes in Bitcoin’s code suggest a concern for protecting private keys if quantum computers become real.
