I decided to make a quick post on how to set a trusted root CA to untrusted in Mac OSX. As some people may or may not know, one of the root CA authorities was recently hacked and several rouge certificates were issued including one with a domain name of .google.com. Now DigiNotar, which is the company in question, claims that the have revoked all the rouge certificates and all is well. However, me being involved in infosec and security I would rather not take any chances so I decided to set DigiNotar to a “trust never” level on my machine for the time being. Below I will outline the few simple steps to do this for any certificate authority on Mac OSX.