Cracking Bitcoin in just 9 minutes? Google warns that the end of elliptic encryption may come sooner than expected, having lowered the attack threshold by 20 times.

ME News message, March 31 (UTC+8), Google’s Quantum AI team released a white paper showing major optimizations to the Shor algorithm. The Shor algorithm can break the elliptic-curve encryption used by Bitcoin and Ethereum; once quantum computers are powerful enough, attackers can derive the private key from the public key and steal funds. The team compiled two sets of attack circuits, each requiring fewer than 1,200 and fewer than 1,450 logical quantum bits (computing units made up of hundreds of physical quantum bits with error correction). On superconducting quantum computers, both circuits can complete the computation within minutes under conditions of fewer than 500,000 physical quantum bits. Previously, the mainstream estimate in academia was about 10 million physical quantum bits; this breakthrough reduces the threshold by roughly 20 times.

Attackers can complete most of the preparatory computations in advance, and crack the private key about 9 minutes after the Bitcoin transaction is broadcast. Bitcoin’s average block time is about 10 minutes, giving attackers roughly a 41% probability of intercepting the funds before the transaction is confirmed. Currently, about 6.9 million Bitcoin (about one-third of the total supply) faces potential risk because their public keys have been exposed, including about 1.7 million from the network’s early days. Google also noted that the Taproot upgrade in 2021 exposes public keys by default, which may further expand the scope of vulnerable wallets.

The team did not publicly disclose the specific implementation of the attack circuits; instead, it released a zero-knowledge proof that allows third parties to verify that the conclusions are correct without disclosing the attack method. Ryan Babbush, Director of Quantum Algorithm Research at Google, and Hartmut Neven, Vice President of Engineering for Google Quantum AI, said that before publication they had already communicated with the U.S. government, and they are currently collaborating with Coinbase, the Stanford Blockchain Research Institute, and the Ethereum Foundation to advance post-quantum migration. Google previously set 2029 as the deadline for migrating its own authenticated services to post-quantum cryptography. Nic Carter, co-founder of Castle Island Ventures, said the paper is “very alarming” and wrote: “Elliptic-curve cryptography is right on the edge of being obsolete. Whether it’s 3 years or 10 years, it’s over, and we need to accept that.” (Source: 1M AI News)