Quantum Computing: The 9-Minute Window to Steal Your Bitcoin

This series explores the intersection of quantum computing and bitcoin security. The first part delved into the physics of quantum computing, while this piece examines the potential threat to bitcoin's encryption. Bitcoin's security relies on elliptic curve cryptography, which uses a one-way function to derive a public key from a private key. However, a quantum algorithm known as Shor's algorithm can potentially break this encryption. The algorithm exploits the properties of quantum mechanics to find the private key, given the public key and a specific curve. This is made possible by the principles of superposition, entanglement, and interference, which enable the quantum computer to evaluate a function on multiple inputs simultaneously and filter out incorrect answers. The attack scenario involves a quantum computer with a large number of stable qubits, which has been estimated to be fewer than 500,000. Google's recent paper reduced this estimate and introduced a practical attack scenario, which includes a nine-minute window to derive a private key and submit a competing transaction. This has significant implications for bitcoin's security, particularly for the 6.9 million coins already exposed on the blockchain.