The emergence of quantum computers poses a significant threat to Bitcoin's security, with the potential to break its core cryptography. In response, developers are exploring various upgrades to build defenses against this threat. Google's recent research suggests that a sufficiently powerful quantum computer could crack Bitcoin's cryptography in under nine minutes, highlighting the urgency of the issue. Approximately 6.5 million bitcoin tokens, worth hundreds of billions of dollars, are vulnerable to a quantum attack.
To mitigate this risk, several proposals are under consideration, including BIP 360, which removes the public key from the blockchain, and SPHINCS+, a post-quantum signature scheme built on hash functions. Other initiatives, such as Tadge Dryja's Commit/reveal scheme and Hourglass V2, aim to protect transactions in the mempool and slow the spending of old coins, respectively. While these proposals are still in development, they demonstrate the Bitcoin community's proactive approach to addressing the quantum threat and ensuring the long-term security of the blockchain.