Quantum Threat to Bitcoin and Ethereum Cryptography Looms Larger

Researchers from Google Quantum AI, the Ethereum Foundation, and Stanford have made significant strides in cracking the code on quantum computers' potential threat to Bitcoin and Ethereum. According to a recent whitepaper published by the team, fewer than 500,000 physical superconducting qubits would be needed to break the elliptic curve cryptography underpinning both cryptocurrencies.

This is a major reduction from prior estimates of roughly 9 million qubits required for the same task. The researchers focused on solving the 256-bit elliptic curve discrete logarithm problem (ECDLP-256), which is crucial in keeping private keys secure. They used Shor's algorithm targeting the secp256k1 curve, shared by both Bitcoin and Ethereum.

The study suggests that a quantum computer could theoretically intercept public keys during transactions, allowing for private key derivation before the transaction is confirmed. The researchers estimate approximately 41% success probability under certain conditions for this type of attack.