Bitcoin and Ethereum Quantum Attack Estimate Cut by Over 50%

Crypto researchers have made significant progress in optimizing quantum algorithms that could potentially attack Bitcoin and Ethereum. A paper published by a team of researchers from various organizations, including the Ethereum Foundation and Theta Labs, describes a new quantum circuit that uses fewer qubits and gates than previously thought necessary to breach the cryptography used by these two popular cryptocurrencies.

The estimated work needed for a key step in a future quantum attack on Bitcoin and Ethereum has fallen by more than 50% from a benchmark Google published in March. The researchers optimized point addition, a calculation performed repeatedly inside Shor's algorithm, which is the quantum algorithm that could eventually turn an exposed public key into the private key behind it.

The new circuit scores about 1.5 billion, with a second version adapted more closely to how Shor's algorithm would actually use the calculation scoring about 1.96 billion. This is significantly lower than Google's reported figures of roughly 3 billion.