The notion that a quantum computer could potentially derive a bitcoin private key from a public key in approximately nine minutes has sent shockwaves through the crypto community. To understand the implications, it's essential to grasp how bitcoin transactions work. When a bitcoin transaction is made, the sender's wallet uses a private key to sign the transaction, while the public key is shared with the network.
The public key is linked to the private key through a complex mathematical problem known as the elliptic curve discrete logarithm problem, which classical computers are unable to solve in a practical timeframe. However, a sufficiently powerful quantum computer could potentially solve this problem using an algorithm called Shor's algorithm. The recent study found that a quantum computer could be 'primed' in advance by pre-computing parts of the attack, allowing it to derive a private key in about nine minutes once the public key appears in the mempool. This gives the attacker a roughly 41% chance of stealing the funds before the original transaction is confirmed.
The bigger concern is the 6.9 million bitcoin that are already vulnerable to quantum attacks due to exposed public keys. This includes early bitcoin addresses and wallets that have reused addresses, making them susceptible to attack.
The bitcoin network itself would continue to function, but the ability to derive private keys from public keys would undermine the security of the network, making it vulnerable to theft and collapsing institutional trust. The solution lies in post-quantum cryptography, which would replace the vulnerable math with algorithms that quantum computers cannot crack.