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

The security of bitcoin relies on a complex system called elliptic curve cryptography, which utilizes a one-way mathematical function to prove ownership of coins. However, a quantum algorithm known as Shor's algorithm can potentially break this encryption, allowing an attacker to derive a private key from a public key. This process, which was previously thought to require millions of physical qubits, has been simplified by Google's recent paper, reducing the required number of qubits to fewer than 500,000. The paper introduced a practical attack scenario, where a quantum computer can precompute certain parameters and then finish the calculation in approximately nine minutes once a target public key is identified. This timing is critical, as it coincides with bitcoin's average block confirmation time, giving the attacker a roughly 41% chance of succeeding. Furthermore, approximately 6.9 million bitcoins are vulnerable to an 'at-rest' attack, as their public keys have already been exposed on the blockchain. The implications of this quantum threat and the potential consequences for bitcoin users will be explored in the next article.