Quantum Computers Are a Million Times Too Small To Hack Bitcoin

MattSparkes shares a report from New Scientist: Quantum computers would need to become around one million times larger than they are today in order to break the SHA-256 algorithm that secures bitcoin, which would put the cryptocurrency at risk from hackers. Breaking this impenetrable code is essentially impossible for ordinary computers, but quantum computers, which can exploit the properties of quantum physics to speed up some calculations, could theoretically crack it open. [Mark Webber at the University of Sussex, UK, and his colleagues] calculated that breaking bitcoin's encryption in this 10 minute window would require a quantum computer with 1.9 billion qubits, while cracking it in an hour would require a machine with 317 million qubits. Even allowing for a whole day, this figure only drops to 13 million qubits. This is reassuring news for bitcoin owners because current machines have only a tiny fraction of this -- IBM's record-breaking superconducting quantum computer has only 127 qubits, so devices would need to become a million times larger to threaten the cryptocurrency, something Webber says is unlikely to happen for a decade. The study has been published in the journal AVS Quantum Science.

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