Quantum Computing Threats and Post-Quantum Cryptography

Quantum Computing Threats and Post-Quantum Cryptography

Quantum computing represents an existential threat to current public key cryptography underlying SSL certificates. Quantum computers could potentially break RSA and elliptic curve cryptography that protect today's internet communications. While practical quantum computers remain years away, the threat is immediate for data requiring long-term confidentiality. Encrypted data collected today could be stored and decrypted once quantum computers become available.

Post-quantum cryptography development accelerates as the threat becomes more tangible. NIST's Post-Quantum Cryptography Standardization process has selected algorithms for standardization, including lattice-based, code-based, and hash-based approaches. These algorithms resist both classical and quantum attacks but typically require larger key sizes and signatures. The transition to post-quantum algorithms will require careful planning and extended migration periods.

Hybrid approaches combining classical and post-quantum algorithms provide transition strategies. These implementations use both traditional and quantum-resistant algorithms, ensuring security against current threats while preparing for quantum computers. Certificate authorities and browser vendors are experimenting with post-quantum certificates and protocol extensions. Organizations should monitor these developments and plan for eventual migration, particularly for systems handling long-term sensitive data.