While most Bitcoin remains secure today, researchers warn that around 6.9 million BTC could become vulnerable if quantum computing makes major breakthroughs. The exposure mainly comes from older address formats, including early Pay-to-Public-Key (P2PK) addresses and reused wallet addresses that reveal public keys on the blockchain.

These coins could theoretically be targeted if future quantum machines manage to break Bitcoin’s elliptic curve cryptography. However, experts say this scenario would require highly advanced quantum systems that do not yet exist. For now, the industry sees the threat as a future challenge, not an urgent crisis, giving the ecosystem time to migrate funds and improve security standards.