High-reliability OCSP stapling and why it matters

At Cloudflare our focus is making the internet faster and more secure. Today we are announcing a new enhancement to our HTTPS service: High-Reliability OCSP stapling. This feature is a step towards enabling an important security feature on the web: certificate revocation checking. Reliable OCSP stapling also improves connection times by up to 30% in some cases. In this post, we’ll explore the importance of certificate revocation checking in HTTPS, the challenges involved in making it reliable, and how we built a robust OCSP stapling service.
Why revocation is hard
Digital certificates are the cornerstone of trust on the web. A digital certificate is like an identification card for a website. It contains identity information including the website’s hostname along with a cryptographic public key. In public key cryptography, each public key has an associated private key. This private key is kept secret by the site owner. For a browser to trust an HTTPS site, the site’s server must provide a certificate that is valid for the site’s hostname and a proof of control of the certificate’s private key. If someone gets access to a certificate’s private key, they can impersonate the site. Private key compromise is a serious risk Continue reading

