What Is Q-Day? The Quantum Threat to Bitcoin Explained

Quantum computers today do not pose a significant threat to Bitcoin, but advancements in quantum technology from companies like Google and IBM suggest that this may change soon. Experts warn about 'Q-Day', a hypothetical point in the future when a powerful quantum computer could forge Bitcoin’s digital signatures, allowing unauthorized transactions. The risk is particularly high for early wallet holders whose public keys have been exposed. Current encryption methods used by Bitcoin rely on elliptic-curve cryptography, making them vulnerable to quantum attacks, especially those targeting older wallets that have already revealed their public keys. Proposals are being discussed within the Bitcoin community to transition to post-quantum digital signatures to secure funds. Solutions range from non-intrusive changes to extensive network migrations. However, the decentralized nature of Bitcoin complicates rapid implementation of these proposals. There is concern about a potential panic in the market, as uncertainty about quantum advancements could lead to premature reactions, undermining confidence in Bitcoin even before a quantum attack occurs.

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