Europol says quantum computing won’t break Bitcoin, but some wallets are exposed

Threat Assessment

Europol's European Cybercrime Centre has weighed in on the potential impact of quantum computing on cryptocurrencies. The primary report, titled 'Quantum Computing and Cryptocurrencies – Bridging Technical Expertise and Decision-Making,' finds that the blockchain itself is not at risk.

Key Findings

The report highlights the difference between the blockchain's security and wallet security. Europol states that the blockchain's integrity is ensured by hash functions like Bitcoin's SHA-256, which are resistant to quantum attacks. However, wallet security is a different story. The report identifies public-key cryptography wallets as the primary point of exposure, as a sufficiently powerful quantum computer could work backward from an exposed public key and derive the matching private key.

Vulnerable Addresses

Approximately 6 to 6.9 million BTC sit in addresses whose public keys have already been exposed, representing roughly 30% of Bitcoin's supply. This poses a significant risk to holders, as exposed keys cannot be secured retroactively.

Recommendations

Europol recommends a phased adoption of post-quantum cryptography (PQC) paired with wallet upgrades. PQC refers to encryption schemes designed to withstand quantum computers.

Challenges

However, implementing this solution is not without its challenges. The report estimates that migrating all Bitcoin unspent transaction outputs (UTXOs) could require over 76 days of cumulative processing time under certain assumptions.

Conclusion

For investors, the issue is not whether Bitcoin as a network survives quantum computing, but rather whether a specific holder's coins are in vulnerable addresses. Europol's analysis emphasizes the need for proactive migration to secure these funds.