How do I install the L1K Chain Certificates on OS 10? I recently tried to open an application for work and it gave me an error message stating the following: You have not chosen to trust "Entrust Certification Authority - L1K", the issuer of the server's security certificate.
MacBook Pro (Retina, 13-inch, Late 2013), OS X Mavericks (10.9.5)
If you had a certificate that came from the dozens of "well-known" certificate issues included with your mac, it would have looked up the chain of Trust and the certificate would be trusted automatically.
Since your certificate issuer is not on that list, you need to decide: do you trust that Certificate Authority?
There are some complex ways you are "supposed to" do this. These could include being handed a copy of a Certificate or Certificate Authority on a Read-only medium (like a CD) by your Network Administrator at work (provided you trust that person). Then Install that on your computer, and (provided the CD has never left your oversight) you can mark that Certificate or Certificate Authority as "Always Trust".
What is NOT an acceptable way of proceeding is to download something that purports to be the Certificate or Certificate Authority and then Trust it. You do not know where that has been, and whether it has been changed along the way.
As a practical matter, most folks just display the certificate, and (for non-nuclear secrets) if the rest of everything else looks right, you mark the Certificate Authority as "Always Trust". Good enough.
This article seems to describe the latter, rather vague, method specifically regarding email certificates. It also reminds us we can use Keychain Access to make changes to Trust of Certificates:
Mail (Yosemite): Trust a certificate
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Entrust Certificates
