A Google study reveals reduced qubit requirements for cracking crypto codes, raising concerns about blockchain vulnerabilities.
Google has released new research estimating that quantum computers require significantly fewer qubits to break the cryptography securing major cryptocurrencies. The study focuses on elliptic curve cryptography, commonly used in blockchains like Bitcoin and Ethereum.
According to the research, a quantum computer could crack a 256-bit elliptic curve discrete logarithm problem with under 500,000 physical qubits, marking a 20-fold reduction from earlier estimates. This was tested on a superconducting-qubit system.
Implications for Bitcoin
For Bitcoin, the research suggests a quantum computer could derive a private key from an exposed public key in about nine minutes. This timeframe aligns with Bitcoin's 10-minute block time, enabling a potential 'on-spend attack' to steal funds during transactions.
Ethereum faces risks from 'at-rest attacks,' where exposed public keys from initial transactions could be targeted. Google estimates that the 1,000 wealthiest exposed Ethereum accounts, holding around 20.5 million ETH, could be compromised in under nine days.
Google recommends that blockchains transition to post-quantum cryptography immediately to enhance security. The company set a 2029 deadline for its own migration and urges the cryptocurrency community to act proactively.
Ethereum developers are already addressing these threats, with the Ethereum Foundation releasing a post-quantum roadmap in February. In contrast, Bitcoin's approach has been described as lagging by some experts, though specifics remain tied to ongoing developments.