A group of researchers at Google has announced a new deadline for transitioning to post-quantum cryptography: 2029. This means that Bitcoin and various other cryptocurrencies must implement advanced cryptographic methods that can withstand quantum threats within the next three years.
Google disclosed this updated timeline in a blog entry. The post highlighted, “The advent of quantum computing poses a considerable risk to existing cryptographic norms, particularly concerning encryption and digital signatures.”
This week, two significant papers were released, one authored by Google’s researchers, and the other by a startup named Oratomic, which includes former Google and Caltech team members. While these documents may be complex for those lacking a cryptographic background, their core message is straightforward: they outline new methods for undermining crucial cryptographic systems using quantum technology, requiring significantly fewer resources than previously anticipated.
This discovery is particularly relevant to Bitcoin, as it increases the likelihood of someone being able to construct a quantum computer capable of deriving a Bitcoin private key from its public counterpart. In fact, the risk is now so heightened that Google opted not to reveal the quantum circuits employed for this demonstration, instead opting to provide a mathematical proof confirming its feasibility.
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Justin Drake, one of the co-authors of the Google paper, provides a comprehensive overview. He stated, “A superconducting quantum computer, like the one Google is developing, could potentially crack keys in mere minutes.”
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It’s crucial to clarify: As Adam Back, a notable Bitcoin authority, pointed out, the Bitcoin network does not rely on encryption. What was found by Google doesn’t imply that transactions can be intercepted on the Bitcoin network; instead, the concern lies in the potential for someone to access a private key, leading to the theft of coins.
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Nonetheless, the situation is more intricate than it appears. Both papers refer to Shor’s algorithm—a quantum computing technique invented by Peter Shor in 1994—that accelerates the decryption of specific encryption formats using quantum machines. Shor’s algorithm could potentially enable the extraction of a Bitcoin private key from a public key, applicable in particular scenarios. This includes some legacy Bitcoin addresses, notably those associated with Bitcoin’s enigmatic creator, Satoshi Nakamoto. These addresses collectively hold over one million bitcoins, signifying that breaching them could deliver a reward in the tens of billions of dollars, alongside unprecedented disruption to the network as users scramble to respond.
Newer addresses are also vulnerable, though only after they’ve been included in a transaction, creating a brief (typically around a 10-minute) window during which Shor’s algorithm could be employed to obtain the private key. Presently, there isn’t a known quantum computer capable of achieving this, even with the advancements identified by Google and Oratomic researchers. However, it’s conceivable that such technology could be developed in the future.
Historically, Bitcoin has been slow to implement changes. Adam Back specifically recommended in 2025 that “some level of quantum readiness” should be integrated within the next five years, although he doesn’t anticipate it being utilized “for several decades.”
In contrast, the findings in the recent papers suggest that the quantum threat to Bitcoin is more immediate than previously thought, indicating that proactive measures are necessary now.
So, what steps can be taken? Google’s analysis proposes several strategies that blockchains, including Bitcoin, might consider to counteract the risks. These include straightforward measures, such as transferring funds from outdated addresses to newer ones when feasible, coupled with updating protocols to incorporate post-quantum cryptography. This transition, however, is not trivial for robust, established cryptocurrency networks and could take years just to reach a consensus on the optimal solution (considering how an internal dispute over Bitcoin’s block size required about two years for resolution), much less executing it.
Other cryptocurrencies, such as Ethereum, are similarly at risk from these vulnerabilities. The Ethereum Foundation, which oversees the sustainable advancement of Ethereum, has recently unveiled a post-quantum roadmap, aimed at addressing these challenges before it becomes too late.