Google’s latest research indicates that quantum computers could potentially break the cryptography protecting Bitcoin and Ethereum using fewer than 500,000 physical qubits, a significant reduction from previous estimates. Researchers tested two quantum circuits on a superconducting-qubit, cryptographically relevant quantum computer (CRQC) and reported a “20-fold reduction” in qubits needed to solve the 256-bit elliptic curve discrete logarithm problem (ECDLP-256), vital for securing cryptocurrencies.
The findings suggest that a quantum computer could crack a Bitcoin private key in as little as nine minutes, allowing for an “on-spend attack” during Bitcoin’s ten-minute block time. An “on-spend” attack would involve deciphering a private key from a public key revealed in a transaction, potentially resulting in the theft of funds.
Justin Drake, a co-author and Ethereum researcher, expressed increased confidence in the likelihood of a quantum computer recovering private keys by 2032, estimating at least a 10% chance. He stated, “My confidence in Q-Day by 2032 has shot up significantly.”
Furthermore, the researchers warned that Ethereum is susceptible to “at-rest attacks,” which can derive private keys from exposed public keys without a time constraint. This vulnerability arises once an Ethereum account makes its first transaction, making its public key permanently visible.
Google estimated that the 1,000 wealthiest exposed Ethereum accounts, holding around 20.5 million ETH, could be compromised in under nine days. The company aims to raise awareness about these vulnerabilities, urging the cryptocurrency community to adapt security measures.
In light of these findings, Google recommended that blockchains transition to post-quantum cryptography (PQC) immediately rather than waiting for actual quantum threats. On Wednesday, Google established a 2029 deadline for its migration to PQC, suggesting that “quantum frontiers” could arrive sooner than expected.
On Thursday, crypto entrepreneur Nic Carter noted that elliptic curve cryptography is nearing obsolescence. He indicated that Ethereum developers are addressing these vulnerabilities, while Bitcoin developers are lagging. The Ethereum Foundation revealed its post-quantum roadmap in February, with co-founder Vitalik Buterin highlighting the need for changes in validator signatures, data storage, accounts, and proofs to counter quantum threats.
