identity_path field in the configuration file must be populated, and its value
shall be the absolute path to the identity file on the device. It’s recommended
to use the identity file, as opposed to the configuration file, to persist
device-unique credentials.
A number of fields in TUC’s configuration file can be overridden with the
identity file. This can allow you to use a single configuration file across
multiple projects. See the configuration file for
more information.
Example identity file configuration:

