News about the risk of quantum computers
A waver of the D-Wave quantum computer. Doesn’t look that adventurous. Image by Steve Jurvetson via Flickr.com. License: Creative Commons
Initially, Germany’s chief supervisor Mark Branson warned that Bitcoin was not quantity -safe. Now the Tether boss Paolo Ardoinino comments on the threat. We incorporate the risks through quantum computers sober.
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Quantum computers are a little for Bitcoin what the grin for Christmas is: a malicious spirit in a mountain that could blow up the party at any time.
At least that’s how it is said again and again. Finally, even by Mark Branson, the President of the Federal Financial Service Supervisory Authority (BaFin), which Bitcoin should monitor and should therefore know. At a press conference at the end of January, Branson warned that cryptography at Bitcoin was not quantity -safe.
In fact, the SHOR quantum algorithm can potentially break the signature algorithm ECDSA, which secures Bitcoin. Therefore it is always said that it is only a matter of time before Bitcoin is broken.
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Shortly afterwards, Markus Pflitsch, entrepreneur, investor and expert for quantum computers, also warned in BTC echo “Why Bitcoin is in danger”: Quantum computers are a gamuchanger, the quantum revolution is already beginning, and it is urgently necessary to establish quanta-proof cryptography. That sounds dramatic.
Last week the Tether CEO Paolo Ardoinino intervened in the debate: he wrote a “prediction” on Twitter: All Bitcoins “in lost wallets, including those from Satoshi (if he no longer lives), are hacked and brought back into circulation.”
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Ardoinino, truly not a Bitcoin skeptic, the highest financial supervisor in Germany?
How far quantum computers are away from being dangerous
Not quite. Ardoino also explains that quantum computers “are still very far away from being a serious risk of Bitcoin’s cryptography.”
A danger to ECDSA arises at the earliest when quantum computers 1.500 to 2.Reach 000 physical qubits. Only then will SHOR be able to play his “quantum superiority”, i.e. be more effective than a conventional computer. It is estimated that it would be 6.000 qubits still need five years to break an ECDSA signature. To do this in an hour, a quantum computer already needs 317 million qubits.
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At the end of 2023 atom computing had announced, more than 1 for the first time.To have connected 000 qubits. At the end of 2024 atom computing and Microsoft presented a quantum computer together, which should be available commercially from 2025. Microsoft does not call the number of physical quBITs, but praises that it has reached the largest number of logical quBITs so far – namely 24.
To attack ECDSA with the SHOR-algorithm, you need at least 1.500 logical qubits. Microsoft is still very far from that.
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Google with its latest quantum computer Willow, on the other hand, has been working with 105 physical qubits so far. Willow supposedly, Google, made an invoice in seconds, for which a conventional supercomputer would need billions of years. In fact, the formula was specially written for the fact that only quantum computers can solve it and otherwise meaningless. In order to be able to calculate even normally, Willow would need ten times as many quants as before.
Quantum computers are currently still very far from breaking Bitcoin signatures. If at all, then in decades, and only if there is a breakthrough in quantum computing. But even then Bitcoin is not broken, as some may think.
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Most bitcoins are not affected
Bitcoins are no longer connected to public keys on the blockchain, but with addresses. These are held derivations of the public keys. Since Shor can only attack the keys, but not addresses, all bitcoins that are on addresses are certain as long as the address is only used once.
A quantum hacker could be over 6.000 physical (or 1.500 logical) quBITs, only attack coins from an early phase from Bitcoin when they were still transferred to public keys. These include the many Bitcoins from Satoshi. The hacker could crack this, which would take around five years each with 50 bitcoins. In order to give away seriously, you either need a lot of these quantum computers or a lot more quBits.
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Normal users who use the right addresses do not run any danger as long as they do not use the address twice. Only when you reveal the public key – i.e. if you send a transaction – can a quantum hacker attack. However, he has less than ten minutes to break a signature and try a double spend before the transaction is confirmed. Even with 317 million qubits, a currently unreachable number, he would need an hour for it.
The future crash
Bafin boss Mark Branson and Tether CEO Paolo Ardoinino speak of a very distant threat. At some point, long “before there is a serious danger to Bitcoin”, Ardoino predicts, “quantum -resistant addresses are added.“All people who have life and access to their wallets will switch to these new addresses early on.
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It’s about a time when quantum computers approach strength to break ECDSA in less than ten minutes. In fifty years when things go very well for quantum computers, probably not in our century, and probably never.
Until then, however, the wallets that still use public keys and do not even migrate on addresses will have long since been broken. These bitcoins, a total of a total of a few million, will then be brought back into circulation. So we can expect a big crash in the second half of the 21. Century.
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