[id='proc_adding-new-certificates']
= Adding New Certificates

Often, system administrators want to install a certificate into the trust store. This can be done with the [command]`trust anchor` sub-command of the [command]`trust` command, as described in xref:managing-trusted-system-certificates[Managing Trusted System Certificates].

Alternatively, you can simply copy the certificate file in the PEM or DER file format to the `/etc/pki/ca-trust/source/anchors/` directory, followed by running the [command]`update-ca-trust` command, for example:

[subs="+quotes,macros"]
----
# cp _~/certificate-trust-examples/Cert-trust-test-ca.pem_ _/etc/pki/ca-trust/source/anchors/_
----

----
# update-ca-trust
----

The [command]`update-ca-trust` command ensures that the certificate bundles in application-specific formats, such as Java keystore, are regenerated.

[NOTE]
====
The certificates installed in the above steps cannot be removed with the [command]`trust anchor --remove`.
====

[NOTE]
====
While the Firefox browser is able to use an added certificate without executing [command]`update-ca-trust`, it is recommended to run [command]`update-ca-trust` after a CA change. Also note that browsers, such as Firefox, Epiphany, or Chromium, cache files, and you might need to clear the browser's cache or restart your browser to load the current system certificates configuration.
====