The Quantum Threat to Bitcoin: How a Powerful Computer Can Steal Your Cryptocurrency in Under 10 Minutes

Understanding quantum computers is crucial, but it's equally important to know how they can be used to steal bitcoin. This involves understanding the target - bitcoin's security system. Bitcoin uses elliptic curve cryptography, which relies on a one-way map, making it virtually impossible for classical computers to reverse the math. However, a quantum algorithm known as Shor's algorithm can break this security by solving the discrete logarithm problem efficiently. Google's recent paper reduced the estimated number of qubits required to run this algorithm, making the threat more real. The paper introduced a practical attack scenario where a quantum computer can precompute parts of the algorithm and then finish the calculation in about nine minutes once a target public key appears. This gives the attacker a significant chance of stealing bitcoin before a transaction is confirmed. The bigger concern is the large number of bitcoin that are already vulnerable to an 'at-rest' attack, which can be executed without time pressure. The implications of this threat and the ongoing development of quantum computing hardware will be discussed in the next part of this series.