Bitcoin faces an existential threat from quantum computing that could break its cryptographic signatures. The core issue is that current Bitcoin addresses using ECDSA signatures would be vulnerable if a cryptographically-relevant quantum computer (CRQC) emerges. This would require both code changes and widespread wallet migrations to maintain security.

Google has set a timeline for post-quantum cryptography adoption by 2029, while experts suggest a 10% chance of CRQC existing by 2030. Historical precedent shows Bitcoin soft forks like Taproot take years to implement and deploy across the ecosystem. Using these estimates, there's potentially a 5% chance Bitcoin could fail by 2030 if no upgrades occur.

The technical challenges are substantial: choosing appropriate post-quantum signature schemes that balance security with performance, determining how consensus handles legacy addresses, and coordinating wallet and exchange upgrades. Bitcoin currently lacks support for quantum-resistant signatures, requiring a soft fork to enable them. The ecosystem must then migrate users away from vulnerable address types before quantum computers arrive.