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 update: March 31 (UTC+8). Google’s Quantum AI team released a white paper showing major optimizations to Shor’s algorithm. Shor’s algorithm can break the elliptic-curve cryptography used by Bitcoin and Ethereum; once quantum computers become powerful enough, attackers can derive private keys from public keys and steal funds. The team compiled two sets of attack circuits, each requiring fewer than 1200 and fewer than 1450 logical qubits (computation units formed by hundreds of physical qubits through error correction). On superconducting quantum computers, both circuits can complete computation within minutes under the condition of fewer than 500,000 physical qubits. Previously, the mainstream academic estimate was about 10 million physical qubits; this breakthrough lowers the threshold by roughly 20x.

Attackers can complete most of the preparation calculations in advance, cracking the private key about 9 minutes after Bitcoin transaction broadcasting. Bitcoin’s average block time is about 10 minutes, giving attackers about a 41% chance of hijacking funds before the transaction is confirmed. At present, about 6.9 million Bitcoins (roughly one-third of the total supply) face potential risk because their public keys have been exposed, including about 1.7 million Coins from the network’s early days. Google also noted that the 2021 Taproot upgrade 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 revealing the attack method. Ryan Babbush, Director of Research for Google’s Quantum Algorithms, and Hartmut Neven, Vice President of Engineering for Google’s Quantum AI, said that before publication, the team had communicated with the U.S. government and is now 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 moving its own certified services to post-quantum cryptography. Castle Island Ventures co-founder Nic Carter said the paper is “extremely alarming,” and wrote: “Elliptic-curve cryptography is on the obsolete edge. Whether it’s 3 years or 10 years, it’s done—we have to accept that.” (Source: 1M AI News)