THE QUANTUM INTELLIGENCER

INTELLIGENCE BRIEFING: Quantum Threat Horizon – Critical Vulnerabilities in Classical Cryptography and the Post-Quantum Transition Executive Summary: Quantum computing advancements have invalidated the long-term security of classical cryptographic standards (RSA, ECC, DH), necessitating immediate strategic migration to quantum-resistant algorithms. NIST-standardized post-quantum cryptography (PQC) candidates—Kyber, Dilithium, and Falcon—offer viable replacements but present performance and integration trade-offs. Hybrid models are currently the most pragmatic defense during transition. This briefing outlines core risks, evaluates leading PQC alternatives, and provides actionable guidance for securing digital infrastructure against near-term quantum decryption threats. Primary Indicators: - Classical public-key systems (RSA, ECC, Diffie-Hellman) are vulnerable to Shor’s algorithm on sufficiently advanced quantum computers - NIST has selected Kyber (KEM), Dilithium (signature), and Falcon (signature) as foundational post-quantum standards - performance benchmarks show increased key sizes and computational latency in PQC schemes compared to classical counterparts - major tech firms and government agencies are implementing hybrid cryptography to ensure backward compatibility and forward secrecy - migration timelines suggest critical infrastructure must begin PQC integration by 2026 to mitigate 'harvest now, decrypt later' attacks Recommended Actions: - Initiate inventory of cryptographic assets to identify systems reliant on quantum-vulnerable algorithms - prioritize high-value data and long-life systems for early PQC migration - adopt hybrid encryption models combining classical and post-quantum schemes during transition - engage with NIST PQC standardization updates and vendor roadmaps - conduct pilot deployments of Kyber and Dilithium in non-critical environments to assess operational impact - train security teams on quantum risk awareness and PQC implementation best practices Risk Assessment: The cryptographic foundations of global digital trust are approaching a point of irreversible fragility. Systems still reliant on RSA or ECC after 2030 will be exposed to catastrophic compromise by state-level quantum adversaries capable of executing Shor’s algorithm at scale. Evidence suggests that encrypted data is already being harvested in anticipation of future decryption—a silent breach with strategic consequences. The window to act is narrowing: those who delay migration risk inheriting an obsolete security posture, where today’s secrets become tomorrow’s disclosures. Authority in cyberspace will soon belong not to those with the strongest firewalls, but to those who secured their past before the quantum key turned. —Ada H. Pemberley Dispatch from The Prepared E0