The security of almost all modern cryptography — including Bitcoin, Ethereum, and every other blockchain — rests on mathematical problems that are computationally hard for classical computers. Factoring large numbers. Computing discrete logarithms. Finding hash preimages.
Quantum computers change the calculus. Some of these problems, which take classical computers millions of years to solve, could be solved by quantum computers in hours.
How worried should crypto be?
The Specific Threats
Public key cryptography (ECDSA): The signature scheme used by Bitcoin and Ethereum is vulnerable to Shor's algorithm — a quantum algorithm that can extract private keys from public keys. If a sufficiently powerful quantum computer existed, it could steal anyone's Bitcoin by deriving their private key from their public key.
SHA-256 (Bitcoin mining): Less vulnerable. Grover's algorithm provides only a quadratic speedup, which is manageable. The mining difficulty could be adjusted.
The timeline: Current quantum computers have hundreds to low thousands of error-prone qubits. Breaking ECDSA would require millions of error-corrected qubits. We're probably 10-20 years away from that capability — but "probably" is doing a lot of work in that sentence.
What the Blockchain Community Is Doing
- NIST has published post-quantum cryptography standards (CRYSTALS-Kyber, CRYSTALS-Dilithium)
- Ethereum developers have discussed quantum-resistant signature schemes
- The "harvest now, decrypt later" attack is already a concern for long-lived encrypted data
Should $AIREVOLT Worry?
The Broader Lesson
The quantum threat is a reminder that no technical solution is permanent. Cryptographic standards that seem unbreakable today may be vulnerable tomorrow. Building with adaptability is as important as building with security.
The crypto projects that thrive long-term will be the ones with communities and infrastructure resilient enough to survive necessary technical migrations. That resilience is worth building now.