Quantum Computing Researchers Cut Estimated Cost of Attacking Bitcoin, Ethereum Encryption

A team of researchers has made significant progress in reducing the estimated cost of attacking Bitcoin and Ethereum encryption using quantum computing. According to a paper published on September 10, the team of over 100 contributors was able to cut the estimated computing resources needed to break the encryption protecting Bitcoin and Ethereum wallets by more than half.

The research focused on elliptic-curve point addition for the secp256k1 curve, which is used by both Bitcoin and Ethereum to keep private keys secure. The team refined this single arithmetic component of Shor's algorithm, rather than modeling an entire attack. This distinction matters because it narrows estimates of what a future fault-tolerant machine would require.

The paper notes that the comparison with Google Quantum AI's March estimate is not perfectly direct due to different accounting methods. However, the team achieved an 86.1% reduction from its own internal starting point and more than halved the estimated cost relative to Google's figure.

The research highlights the potential vulnerability of wallets where the full public key is already visible on-chain. Approximately 6.9 million BTC and 20.5 million ETH face similar exposure, making it essential for blockchain developers to plan a migration to quantum-resistant cryptography. Jieyi Long, lead author of the paper, emphasized that roughly a third of all Bitcoin already sits in addresses where the public key is visible.