A team of Google researchers just set a new date for post-quantum cryptography migration: 2029. Among other things, this means that Bitcoin, as well as many other cryptocurrencies, needs to adopt new cryptographic techniques that are resilient to quantum attacks within three years. Google announced the new timeline in a blog post. Important point: As Adam Back, an important Bitcoin expert, pointed out, Bitcoin (the network) does not use encryption.
Shor’s algorithm could be used to derive a Bitcoin private key from a public key, but only in certain cases. This includes some old Bitcoin addresses, including those used by Bitcoin’s elusive creator Satoshi Nakamoto himself; this is notable, as these addresses hold over one million bitcoins, meaning that the potential prize for someone cracking them is in the tens of billions of dollars. Newer addresses can also be cracked, but not until they’re broadcasted within a transaction, meaning there’s a short (typically 10-minute long) window in which someone could use Shor’s algorithm to get that private key. Bitcoin is traditionally slow to make any changes.
Adam Back, in particular, advised in 2025 that “some quantum readiness” should be added in the next five years, though he said he’s not expecting it to be used “in a few decades”. What can be done? Google’s paper suggest ways in which blockchains (including Bitcoin) could mitigate the issue. This includes simple steps such as moving coins from old addresses to new ones if possible, but also updating protocols to include post-quantum cryptography. This process is not easy for large, established cryptocurrency networks, and it may take years to even agree on a best solution.
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