Revocation
OCSP Magic Number
The magic number is a value that states when CRLs will be processed over OCSP, specifically it is when the total number of cached OCSP responses from a single OCSP responder URL on behalf of a single certificate authority will stop performing OCSP and start processing CRLs. This will occur if the number of cached…
Read MoreIgnore Revocation Checking – The bane of my existence!
As students in my PKI training classes know, one of the areas I am a vocal about is the blind use of the CRLF_REVCHECK_IGNORE_OFFLINE setting in a PKI environment. I am so adamantly against the use of this setting, I personally refuse to ever explicitly share or type the syntax to enable this nasty beast.…
Read MoreWhat Your Browser Doesn’t Tell You Can Hurt You – Revocation and Internet Explorer
One of the topics I have been using as an example of revocation checking behavior in my PKI In-Depth class is the interesting case of Internet Explorer (IE) and its revocation behavior. Let’s take a moment and have you think about your assumption of how IE is behaving when you go to a HTTPS (SSL/TLS)…
Read MoreCertificate Transparency Enforcement and Microsoft CAs – Oct 2017 Deadline
To address some weaknesses in the public PKI trust process, Certificate Transparency (CT) was created to make it easier to detect and track fraudulent certificate issuance and use. The intent is that a small collection of log servers would contain information about valid certificates and browsers can check the log to see if a given certificate…
Read MoreMicrosoft OCSP Responders – Trust, Renewals and RFC 6960
Online Certificate Status Protocol (OCSP) provides an efficient mechanism for distributing certificate revocation information. When certificates are exchanged and validated, computers need to determine if the certificate has been revoked – meaning the CA has reason to consider the certificate as untrusted. This often placed in a Certificate Revocation List (CRL). Clients download this potentially large CRL…
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