Quantum Computing Poses Immediate Threat to $150 Billion in Crypto Assets, Google Warns

A new whitepaper from Google Quantum AI warns that the practical arrival of quantum computing could rewrite the security foundation of major cryptocurrencies like Bitcoin and Ethereum. The research indicates a sufficiently powerful quantum machine could break the cryptographic algorithms protecting these networks in minutes, jeopardizing both active and long-dormant assets.

The paper specifically highlights a threat to approximately 2.3 million dormant and vulnerable Bitcoin, which could become a multi-billion dollar target for the first entity to deploy a capable quantum computer. Technically, it estimates a future machine with fewer than 500,000 physical qubits could use Shor's algorithm to break Bitcoin's 256-bit elliptic curve encryption in roughly nine minutes.

This speed is comparable to Bitcoin's average block confirmation time, creating a window for attackers to potentially intercept unconfirmed transactions. "When you send Bitcoin, your public key is exposed in the 'mempool' for about 10 minutes before the transaction is confirmed," cites a report from Simplifying AI. Google researchers have theorized a quantum circuit that could derive a private key from that exposed public key in approximately nine minutes.

Ethereum co-founder Vitalik Buterin has echoed similar concerns, suggesting at a recent conference that current elliptic curve cryptography could be broken by quantum computers before the 2028 U.S. presidential election. He urged the network to transition to quantum-resistant cryptography within four years.

The whitepaper acknowledges that a full migration to post-quantum cryptography presents significant political and operational hurdles, as new signatures are larger and would increase bandwidth and storage demands. AI Governance expert Cory Missimore advises institutions to audit their cryptographic inventory, noting, "Those are your agility gaps and your longest-lead-time risk."

The industry now faces a forced migration timeline, balancing technical upgrades against governance challenges, while the fate of dormant assets risks triggering a race between malicious actors and potential "digital salvage" operators.