Post-Quantum is a cryptography company founded in 2009 in London, UK, focused exclusively on post-quantum cryptography (PQC) — the development of cryptographic systems designed to remain secure against threats posed by quantum computers. The company conducts research and develops production-ready technologies based on code-based cryptography. Its most notable technical contribution is NTS-KEM, which was merged with work from Professor Daniel Bernstein to form Classic McEliece, a NIST Round 4 PQC finalist algorithm. Post-Quantum also authored RFC9370, ratified as the IETF global standard for hybrid quantum-safe VPN connectivity. Its solutions are deployed in operational environments, including the protection of NATO communications and securing drone communications in active conflict zones. The company targets governments, defense organizations, and critical infrastructure operators requiring long-term cryptographic resilience. Post-Quantum's approach centers on conservative cryptographic design, standards-based interoperability, and crypto-agility — building architectures that allow organizations to adapt as cryptographic standards evolve. The company holds ISO 27001 and ISO 9001 certifications and actively participates in NIST and IETF standardization processes. Its work spans cryptographic algorithm development, secure VPN connectivity, and quantum-safe communications infrastructure, serving organizations that need to protect sensitive information against both current and anticipated future quantum computing threats.