Part of macOS
trustdCertificate checks
○ Leave it
Checks security certificates for apps and websites.
What it is
Verifies certificates, for example when a website or app makes a secure connection.
If you stop it
macOS starts it again straight away. Leave it.
The verdict
○ Leave it. Part of macOS, or something that starts again by itself. You never need to close these.
In Activity Monitor
trustd
From Procession’s guide, in the words the app shows.