Bitcoin Private Keys Face Quantum Risk in Future

Fidelity Digital Assets warns that future quantum computers could potentially expose Bitcoin's private keys and put funds at risk. Currently, there are no cryptographically relevant quantum computers (CRQCs), but a sufficiently capable system could undermine the mathematical assumptions securing transaction authorization.

The relationship between private keys, public keys, and transaction signatures forms the foundation of Bitcoin ownership and self-custody. Most standard Bitcoin transactions use the Elliptic Curve Digital Signature Algorithm or Schnorr signatures, which rely on the difficulty of solving the elliptic curve discrete logarithm problem with classical computers.

A sufficiently powerful quantum computer running Shor's algorithm could solve that problem and derive private keys from corresponding public keys. Researchers are evaluating quantum-resistant signature systems that rely on hash functions rather than elliptic-curve cryptography, such as SHRINCS.