Preparing for Q-Day: Quantum-Resistant Cryptography

Quantum computing poses an existential threat to current cryptographic standards. Q-Day, the point when a quantum computer can break RSA-2048, is estimated within the next decade. Migration to post-quantum cryptography cannot wait.

NIST Standards

In 2024, NIST finalized three post-quantum cryptographic standards: CRYSTALS-Kyber for key encapsulation, and CRYSTALS-Dilithium and SPHINCS+ for digital signatures. These algorithms are based on lattice problems believed to be resistant to quantum attacks.

Migration Strategy

A practical migration follows a hybrid approach: existing systems add post-quantum algorithms alongside traditional cryptography. This allows gradual transition without breaking compatibility.

Key considerations include key sizes (Kyber public keys are 3x larger than RSA), performance overhead (signature verification is 2-5x slower), and protocol updates (TLS 1.3 requires extension modifications).