# Cloudflare’s Post-Quantum Authentication: Configuring Secure Origin Connections
Cloudflare has recently enabled **post-quantum authentication** support for **Authenticated Origin Pulls (AOP)** and **Custom Origin Trust Store (COTS)**, representing a major milestone in their post-quantum security roadmap. This feature ensures that connections between Cloudflare and customer origin servers are protected against future quantum computing threats.
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## Understanding the Technology
### What Are Authenticated Origin Pulls and Custom Origin Trust Store?
– **Authenticated Origin Pulls (AOP)**: Enables mutual TLS (mTLS) authentication between Cloudflare and origin servers. Cloudflare presents a client certificate to the origin server, ensuring that only authorized connections are accepted.
– **Custom Origin Trust Store (COTS)**: Allows customers to replace the default set of trusted Certificate Authorities (CAs) with their own custom trust store, providing more control over which certificates are trusted.
### Why Post-Quantum Authentication?
While post-quantum encryption has been available since 2022 (for visitor-to-Cloudflare) and 2023 (for Cloudflare-to-origin), **authentication** is the next critical step. Quantum computers could eventually break classical digital signatures, enabling impersonation attacks. To mitigate this, Cloudflare is deploying **Module-Lattice-Based Digital Signature Algorithm (ML-DSA)**, a NIST-standardized post-quantum signature algorithm.
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## Configuration Guide
### Step-by-Step Setup
1. **Generate ML-DSA Certificates**
Use OpenSSL 3.5.0 or later to generate:
– A **CA certificate** (for COTS or AOP)
– A **server certificate** (for origin servers)
– A **client certificate** (for Cloudflare to present to origin)
Example commands are included in the original article for generating ML-DSA-44 keys and certificates.
2. **Upload Origin CA to COTS**
Replace the default trust store with your own CA so Cloudflare trusts only your origin certificates.
3. **Upload Client Certificate for AOP**
Enable zone-level or hostname-level AOP and upload the client certificate Cloudflare will present to your origin.
4. **Set SSL/TLS Mode to Full (Strict)**
COTS requires “Full (strict)” mode to be active. This ensures both encryption and authentication are enforced.
5. **Configure Your Origin Server**
Depending on your setup (COTS, AOP, or both), configure NGINX or your web server to:
– Present the correct server certificate
– Verify client certificates when required
6. **Verify the Connection**
Use tools like `openssl s_client`, packet captures, or server logs to confirm that:
– ML-DSA certificates are being used
– Mutual TLS is working correctly
– No downgrades to insecure algorithms are occurring
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## Frequently Asked Questions (FAQ)
### What is the difference between encryption and authentication in this context?
– **Encryption** protects data confidentiality (prevents eavesdropping).
– **Authentication** verifies identity (prevents impersonation).
Even if data is encrypted, if authentication is weak, attackers could impersonate either Cloudflare or your origin server.
### Why is post-quantum authentication important now?
Recent advances in quantum computing have accelerated industry timelines. While quantum computers capable of breaking RSA/ECC aren’t here yet, now is the time to deploy **hybrid security**—combining classical and post-quantum algorithms.
### Which Cloudflare products support post-quantum authentication?
As of this update:
– **Authenticated Origin Pulls (AOP)**
– **Custom Origin Trust Store (COTS)**
Support is available for ML-DSA-44, ML-DSA-65, and ML-DSA-87, with ML-DSA-44 recommended for most use cases.
### Will using post-quantum certificates affect performance?
Minimal impact. Unlike encryption, which adds overhead during the TLS handshake, authentication with ML-DSA has small, manageable costs. Connection pooling in Cloudflare helps amortize handshake costs.
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## Behind the Scenes
Implementing this feature required updates across Cloudflare’s infrastructure:
– **Control Plane**: Modified to parse and validate ML-DSA certificates using Cloudflare’s internal **CIRCL** library until Go 1.27 adds native support.
– **Data Plane**: Upgraded the **Pingora Origin** service to use BoringSSL, which recently added post-quantum authentication support.
A previous delay in BoringSSL updates caused a brief incident in June 2026, but a rollback and patch restored functionality while maintaining compatibility with older RSA certificates.
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## Conclusion
Cloudflare’s rollout of post-quantum authentication for AOP and COTS marks a significant step toward full quantum-safe infrastructure. By enabling mutual TLS with ML-DSA signatures, organizations can protect their origin infrastructure from both classical and future quantum threats.
As the ecosystem continues to adopt post-quantum standards, Cloudflare remains committed to transparency, rigorous testing, and timely updates. Customers are encouraged to:
– Follow the configuration guide
– Monitor their TLS logs
– Stay informed about new features and platform support
With these tools in place, your origin infrastructure is ready for the post-quantum future.
