How Bitcoin Will Survive Quantum Computing

Bitcoin was designed around a piece of mathematics that a large quantum computer would undo. Its ownership rests on elliptic curve cryptography, where deriving a public key from a private key is trivial but reversing the step is meant to be impossible. Shor’s algorithm removes that guarantee, which is why the phrase quantum resistant bitcoin has moved from a fringe worry to an active engineering programme with real proposals, real deadlines and a genuinely bitter argument about what to do with the coins that cannot be saved. This guide is about the defence rather than the threat. It sets out exactly which bitcoin is exposed, what breaking a single key would actually require in hardware, and the two competing plans for a quantum resistant bitcoin, post-quantum address types and a legacy signature sunset, that would carry the network across. For the sharper question of whether the attack is even possible, our companion pieces on whether bitcoin survives quantum computing and on Google’s Willow chip cover the risk case in depth. Key Takeaways Only exposed public keys are at risk. Bitcoin is safe while a public key stays hidden behind a hash. The danger begins the moment that key becomes visible…