Senior Certificate Authority Architect

Define and guide the end-to-end architecture of Cloudflare’s public Certificate Authority: a high-assurance, highly available system capable of issuing conventional publicly trusted certificates at Cloudflare scale while supporting Merkle Tree Certificates (MTCs) and the evolution toward a post-quantum Web PKI.

You will help determine not only how the CA is implemented, but also its trust boundaries, key hierarchy, issuance architecture, auditability, failure modes, incident response mechanisms, and long-term cryptographic evolution.

Key Responsibilities

• Define and maintain the end-to-end technical architecture of Cloudflare’s public CA across certificate issuance, key management, transparency, revocation, renewal, and relying-party integration.
• Design root and intermediate CA trust hierarchies, signing systems, HSM integration, key ceremonies, key rotation, backup, recovery, migration, and key-compromise response.
• Architect secure, resilient, and highly available issuance services capable of operating at Internet scale and across multiple geographic and failure domains.
• Design certificate lifecycle systems around ACME, domain and IP validation, CAA, Certificate Transparency, pre-issuance linting, revocation, renewal, and large-scale certificate replacement.
• Integrate Cloudflare’s MTC infrastructure, including CA logs, landmarks,, cosigning or mirroring, and interactions with relying parties.
• Develop practical architectures for coexistence and migration between classical X.509 certificates and post-quantum authentication mechanisms.
• Define trust boundaries, security properties, and threat models covering key compromise, unauthorized issuance, software supply-chain compromise, operator error, malicious insiders, infrastructure failure, split views, and cryptographic migration.
• Design systems that make CA behavior observable and independently verifiable through transparency mechanisms, reproducible builds, cryptographic attestations, public operational telemetry, tamper-evident evidence, and audit controls.
• Design failure containment and recovery mechanisms that support safe certificate replacement, revocation, key rotation, and incident response without creating avoidable Internet availability failures.
• Review protocols, architecture, and implementations with an adversarial mindset, identifying assumptions and failure modes that do not hold at Internet scale.
• Work closely with Cloudflare’s cryptography, TLS, security, networking, infrastructure, compliance, product, and operations teams.
• Provide architectural direction, design review, and technical mentorship to engineers implementing and operating the CA platform.

What Makes Cloudflare Special?

We’re not just a highly ambitious, large-scale technology company. We’re a highly ambitious, large-scale technology company with a soul. Fundamental to our mission to help build a better Internet is protecting the free and open Internet.

Project Galileo :
Since 2014, we’ve equipped more than 2,400 journalism and civil society organizations in 111 countries with powerful tools to defend themselves against attacks that would otherwise censor their work, technology already used by Cloudflare’s enterprise customers–at no cost.

Athenian Project :
In 2017, we created the Athenian Project to ensure that state and local governments have the highest level of protection and reliability for free, so that their constituents have access to election information and voter registration. Since the project, we’ve provided services to more than 425 local government election websites in 33 states.

1.1.1.1 :
We released 1.1.1.1 to help fix the foundation of the Internet by building a faster, more secure and privacy-centric public DNS resolver. This is available publicly for…