Bitcoin hacking: Quantum computers are no threat to cryptocurrency

Bitcoin is theoretically weak to being cracked by quantum computer systems, however calculations present they’d should be 1,000,000 instances bigger than those who exist at present

By Matthew Sparkes

Quantum computer systems would want to grow to be about 1,000,000 instances bigger than they’re at present with a purpose to break the algorithm that secures bitcoin, which might put the cryptocurrency in danger from hackers.

The bitcoin community is stored safe by computer systems often known as miners that use a cryptographic algorithm referred to as SHA-256, which was created by the US Nationwide Safety Company. Breaking this code is basically unimaginable for peculiar computer systems, however quantum computers, which may exploit the properties of quantum physics to hurry up some calculations, might theoretically crack it open.

Now Mark Webber on the College of Sussex, UK, and his colleagues have investigated how massive a quantum pc you would want to interrupt bitcoin, when it comes to the variety of qubits, or quantum bits, the equal of peculiar computing bits.

Each bitcoin transaction should be “confirmed” by the community of miners earlier than it’s added to the blockchain, the immutable ledger of who owns what. Every transaction is assigned a cryptographic key throughout this affirmation course of, and cracking the important thing would assist you to take possession of these bitcoins.

“The transactions get introduced and there’s a key related to that transaction,” says Webber. “And there’s a finite window of time that that secret is weak and that varies, however it’s normally round 10 minutes to an hour, perhaps a day.”

Webber’s group calculated that breaking bitcoin’s encryption in a 10-minute window would require a quantum pc with 1.9 billion qubits, whereas cracking it in an hour would require a machine with 317 million qubits. Even permitting for a complete day, this determine solely drops to 13 million qubits.

That is reassuring information for bitcoin homeowners as a result of present machines have solely a tiny fraction of this – IBM’s record-breaking superconducting quantum pc has only 127 qubits, so units would want to grow to be 1,000,000 instances bigger to threaten the cryptocurrency, one thing Webber says is unlikely to occur for a decade.

Though bitcoin is safe for the foreseeable future, there are issues about different encrypted information with a a lot wider window of vulnerability. An encrypted e-mail despatched at present could be harvested, saved and decrypted sooner or later as soon as a quantum pc is accessible – a so-called “harvest now, decrypt later” assault, which some security experts believe is already happening.

“Individuals are already apprehensive as a result of it can save you encrypted messages proper now and decrypt them sooner or later,” says Webber. “So there’s an enormous concern we have to urgently change our encryption strategies, as a result of sooner or later, they’re not safe.”

Journal reference: AVS Quantum Science, DOI: 10.1116/5.0073075