Concerns are being raised again that quantum computers could neutralise bitcoin's cryptographic system, but an analysis says it is hard to see it as a realistic threat at current technology levels. It says there is little basis to expect a quantum computer with cryptographically meaningful capabilities within the next 10 years, and it remains uncertain whether such equipment can be developed.

Bitcoin Magazine, a blockchain media outlet, said on Oct. 1 local time that the core of the debate over whether quantum computers can attack bitcoin is whether they can compute a private key from a public key and steal someone else's bitcoin. The outlet said current quantum computers have not reached the computing power needed to break such cryptographic systems.

Quantum computers are being developed using a range of advanced technologies, including superconducting qubits, neutral atoms, optical tweezers, laser cooling and dilution refrigerators. But achieving results in complex experiments or specific calculations is a separate issue from building a stable, large-scale system capable of attacking real-world cryptographic systems.

A key challenge for quantum computers is qubit stability and error rates. Increasing the number of qubits alone is not enough. Systems must reliably operate at scale while reducing errors that occur during computation. Large amounts of capital are flowing into the quantum computing industry, but the size of investment itself does not mean technology has matured to the level needed for code-breaking.

Some argue that research results announced in quantum computing also need to be distinguished from advances in actual hardware. Even if theoretically important results are published, such as in Google's quantum computing research, whether stable, large-scale equipment exists to implement them is a separate issue. Multiple approaches, including neutral atoms, are being developed competitively, but it remains unclear which technology will ultimately lead to a quantum computer capable of code-breaking.

Theoretical debate continues over whether bitcoin's cryptographic system could be attacked by quantum computers. Bitcoin uses cryptography based on the secp256k1 elliptic curve, and attacking it with a quantum computer would require massive computing power and stable maintenance of quantum states. Some also argue that based only on current understanding of quantum physics, it is hard to conclude that equipment at that level will necessarily emerge in the future.

That does not mean bitcoin developers should stop preparing for the quantum threat. It is difficult to predict precisely when quantum computers will appear and what their technical limits will be. There is also a possibility that new cryptographic vulnerabilities unrelated to quantum computing could be discovered.

As a result, the bitcoin ecosystem is continuing research into post-quantum cryptography that could replace existing cryptographic systems. Reviewing new signature schemes, including P2MR and P2TRv2 as well as SHRINCS, SPHINCS, IBC and ML-DSA, is part of that effort.

For now, the analysis says worries that quantum computers will immediately neutralise bitcoin are far from technical reality. It says research into next-generation cryptographic technology needs to continue to secure the bitcoin network's long-term security, given how difficult it is to predict the speed and direction of quantum computer development.