DigitalIkey.WChain

A KEY STEP IN A QUANTUM ATTACK ON BITCOIN NOW REQUIRES FEWER THAN 900 LOGICAL QUBITS Theta Labs CTO Jieyi Long has developed a quantum circuit performing elliptic-curve point addition on secp256k1, the cryptography used by Bitcoin and Ethereum, with just 874 logical qubits and 2.4 million Toffoli gates. The breakthrough brings the circuit below Google’s previously published upper bounds of 1,175 logical qubits and 2.7 million Toffoli gates. The development could reduce the hardware requirements for a future quantum attack capable of recovering private keys from exposed public keys. However, the circuit represents only one component of Shor’s algorithm, not a complete attack. No full-attack resource estimate incorporating the new design has been published. Current quantum computers remain far from executing such an attack, which would require hundreds of error-corrected logical qubits and tens of millions of quantum operations. The takeaway for Bitcoin is that the theoretical hardware requirements for a quantum attack are falling, but Google’s demonstrated hardware remains far from what’s required.