Quantum Computing Threat & Post-Quantum Cryptography

Quantum computing represents a threat with a unique temporal structure: the risk is not primarily to systems being attacked today but to encrypted data being collected right now that will be decrypted later. State-sponsored intelligence agencies are actively engaged in what cryptographers call 'harvest now, decrypt later' operations—capturing massive volumes of currently unreadable encrypted data with the strategic patience to wait until quantum computers become capable of breaking RSA and elliptic curve cryptography. The intelligence services that invest in this strategy today will hold the keys to today's secrets for decades. NIST's response has been thorough and actionable. In August 2024, NIST finalized three post-quantum cryptographic standards: FIPS 203 (CRYSTALS-Kyber, for key encapsulation), FIPS 204 (CRYSTALS-Dilithium, for digital signatures), and FIPS 205 (SPHINCS+, for stateless hash-based signatures). A fourth algorithm, HQC, is expected to be finalized in 2027. Federal agencies face a 2026 mandate for initial PQC adoption, while quantum-vulnerable algorithms face a hard deprecation deadline of 2035. Organizations using FIPS 140-2 validated cryptographic modules face an immediate compliance cliff: those modules become obsolete on September 21, 2026. The Department of Defense has published detailed migration timelines, and CISA has issued guidance specifically addressing critical infrastructure. IBM's Quantum Safe initiative provides enterprise migration tooling, and major cloud providers have begun offering PQC-compatible TLS implementations. The strategic reality is that migration timelines are long—updating every cryptographic system, library, certificate, and protocol across a large enterprise typically takes three to seven years—which means organizations that have not yet begun their cryptographic inventory are already behind schedule.