# CAs are pre-loaded on the system, but how is it able to get intermediate certs?

I have the following X509 certificate:

-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----


When I open it up in Windows I see a path from the cert to the CA with one intermediate cert:

So the CA is pre-loaded on the system but how is it able to get the intermediate cert?

• Well obviously it must also be present on the system. There is a store for intermediate certificates and it would not hurt to cache those kind of certs either. A lot of protocols also allow the sending of additional certs together with the leaf certificate. – Maarten Bodewes Feb 26 '18 at 19:25

http://cacerts.digicert.com/DigiCertSHA2SecureServerCA.crt