Microsoft opens quantum-safe certificate testing to CAs

Most planning for post-quantum cryptography (PQC) — encryption designed to survive future quantum computers — has focused on keeping data secret. Microsoft argues that authentication is the harder problem, because certificates and the public key infrastructure (PKI) behind them touch far more systems than any single protocol upgrade, and few organisations can list every system that issues, stores or checks a certificate.

What they found

• Microsoft launched its PQC TLS Pilot Program on 27 August 2026, open to certificate authorities in good standing with the Microsoft Trusted Root Program; admissions run on a rolling basis to the end of 2026.
• The pilot uses ML-DSA-87, a lattice-based signature algorithm, with seven pilot roots operated by ComSign, DigiCert, HARICA, IdenTrust Services, Sectigo, Shanghai Electronic Certification Authority and SSL.com.
• Pilot certificates are not publicly trusted and must not be used for production or public websites; support is described as "limited and evolving".
• Windows 11 can test ML-DSA certificates, including with Schannel, from the 28 July 2026 updates onwards.
• Larger certificates and chains may strain handshake size, storage, inspection limits and hardware security modules.

What to do

• Inventory every application, device, appliance and service that depends on certificates, and map both public and private trust hierarchies.
• Ask certificate, PKI, HSM and software vendors for their post-quantum roadmaps and testing options.
• Flag long-lived kit — embedded devices, operational technology, security appliances — that cannot be upgraded quickly.
• Build non-production test environments and treat the move as a multi-year programme with named owners.

Source: Post-quantum authentication: Why organizations should start testing certificate ecosystems now, Microsoft Security Research, 8 October 2026. Summary by the Cyber Risk Barometer.