This assumes you have reviewed IBM GSKit (Global Security Kit) - Getting Started (command line) or IBM iKeyman - Getting Started (GUI). Before validating a certificate in a Key Database file, you will typically first list the certificates in the Key Database file.
GSKit (command line)
The -cert and -validate options can be used to validate that a certificate in a Key Database file is valid. In this example, we are validating the "example.com" certificate in the example.kdb file.
ihs_home/gsk8/bin/gsk8capicmd_64 -cert -validate -db /path/to/example.kdb -label "example.com" -stashed or -pw your_password
If the certificate is deemed to be valid, the following will be displayed.