Quantum computers may be able to break Bitcoin sooner than you think

Advances over the next decade could pave the way for quantum computers powerful enough to crack Bitcoin encryption, new research suggests.

Scientists from the University of Sussex in the UK estimate that quantum systems with 13 million qubits would be sufficient to break the cryptographic algorithm (SHA-256) that secures the Bitcoin blockchain within the space of 24 hours.

Although modern quantum computers come nowhere close to this level of performance (the current record is a comparatively measly 127 qubits), the researchers say significant developments over the next ten years or so could yield quantum machines with sufficient horsepower.

Cracking the Bitcoin algorithm

The ability to break the encryption protecting the Bitcoin network would allow an attacker to hijack transactions and reroute coins into their own wallet. In this hypothetical scenario, the market would surely crumble as soon as an attack became apparent, wiping out hundreds of billions of dollars in value.

For the time being, cryptocurrency enthusiasts can rest easy in the knowledge that cracking the SHA-256 algorithm is impossible with current hardware, but that won’t always be the case.

Manufactured by IBM, the current most powerful quantum system is touted as the first whose performance cannot be reliably replicated by a classical computer, but it’s still a long way shy of the 13 million qubits required to break Bitcoin.

However, there is extensive research ongoing into all aspects of quantum computing, from almost all the world’s largest technology companies. A lot of work is going into increasing the number of qubits on a quantum processor, but researchers are also investigating opportunities related to qubit design, the pairing of quantum and classical computing, new refrigeration techniques and more.

In all likelihood, Bitcoin will fork onto a new quantum-safe encryption method long before a sufficiently powerful quantum computer is developed, but the research raises an important point about the longevity of encryption techniques nonetheless.

As noted by Mark Webber, lead researcher on the project, because advances in quantum computing will inevitably render modern encryption redundant, it would be a mistake to assume that information encrypted today will remain secure tomorrow.

“People are already worried because you can save encrypted messages right now and decrypt them in the future,” said Webber. “There’s a big concern we need to urgently change our encryption techniques, because in the future, they’re not secure.”

Via NewScientist

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