IN AN ARTICLE published in 2012 John Preskill, a theoretical physicist, posed a question: āIs controlling large-scale quantum systems merely really, really hard, or is it ridiculously hard?ā Seven years later the answer is in: it is merely really, really hard.
What Googleās quantum computer means for Bitcoin
Google claims to have achieved āquantum supremacy,ā successfully demoing the worldās most powerful quantum computer. Is it time for Bitcoin holders to panic?
AĀ documentĀ publishedāand deletedāby NASA a few days ago revealed that we could soon be entering a new technological era: Google has achieved “quantum supremacy”āsupposedly.
According to theĀ Financial Times, Google claims to have successfully built the worldās most powerful quantum computer. What that means, according to Googleās researchers, is that calculations that normally take more than 10,000 years to perform, itās computer was able to do in aboutĀ 200 seconds.
Does that mean that we can say goodbye to that sweet cryptography that protects the integrity of Bitcoin and other digital currencies? Probably not.
Hereās why.
For starters, sources at GoogleĀ told FortuneĀ over the weekend that NASA took down the paper because it might have been published without the proper scientific peer review. A scientific publication needs to be evaluated and studied by a panel of experts before its ready for publication. So, it might not evenĀ actuallyĀ be ready.
But letās assume it is. What you need to know about Bitcoin to understand the potential threat of quantum computing is that its architecture relies on two algorithms: ECDSA for digital signatures and SHA-256 as a hash function. If you reuse a wallet address and make a transaction, you expose your public key.
So, yes, a quantum computerĀ could useĀ Shorās algorithmĀ to get your private from your public key, as Jack Matier of the Quantum Resistant Ledger recently explained in aĀ Medium post. But donāt panic just yet.
The most optimisticĀ scientific estimatesĀ say that evenĀ ifĀ this were possible, it wonāt happen during this decade (enough time toĀ fork BitcoinĀ and make it quantum proof).
Also, considering that Googleās machine is 53 only āquantum bitsā (qubits)āa measure of the computerās quantum powerāaĀ research paperĀ on the matter published by Cornell University may give Bitcoin hodlers some peace of mind:
āA 160 bit elliptic curve cryptographic key could be broken on a quantum computer using aroundĀ 1000 qubitsĀ while factoring the security-wise equivalent 1024 bit RSA modulus would require aboutĀ 2000 qubitsā (emphasis added). By comparison, Google’s measly 53 qubits are still no match for this kind of cryptography.
And, once again, it’s even only aĀ theoretical threatĀ assuming that you re-used your address, which was considered a bad practice evenĀ back in Satoshiās day.
Last week a paper on the matter wasābriefly and presumably accidentallyāpublished online. The underlying research had already been accepted by Nature, a top-tier scientific journal, but was still under wraps. The leak revealed that Google has achieved what Dr Preskill dubbed in his article, āquantum supremacyā. Using a quantum computer, researchers at the information-technology giant had carried out in a smidgen over three minutes a calculation that would take Summit, the worldās current-best classical supercomputer, 10,000 years to execute.
And a SHA-256 cryptographic hash is a different thing altogether. It is so powerful that,Ā according toĀ crypto evangelist Andreas Antonopolulos, the amount of computational power needed to crack it āis greater than the wildest speculation of what intelligence agencies might haveāāand thatās assuming they have quantum computers.
Whatās more, not only can quantum-computing scientists not break Bitcoin yet, they donāt seem too interested in doing so anyway. In fact, one of the most evident use cases for quantum technology appears to be toĀ improveĀ encryption and cybersecurity techniques, according to Googleās own researchers.
But that isnāt to say that thereās no cause for alarmĀ at all. While the native encryption algorithms used by Bitcoin and other proof-of-work coins are safe for now, the fact is that the rate of advancements in quantum technology is increasing, and that could, in time, pose a threat. “We expect their computational power will continue to grow at a double exponential rate,” Google researchers said in the since-deleted document.
Thankfully, there are already companies and research teams working on new cryptography algorithms for aĀ post-quantum era. And, with that in mind, it may not be a bad idea to start thinking about a potential Bitcoin hardfork in a few decades that improves its āweakā security algorithm.