---+ Package =TWiki::Configure::Checkers::CertificateChecker=
Configure GUI checker for Certificate items.

This checker validates files that contain X.509 certificates,
such as for the S/MIME signatures and for the Tasks framework.

It must be subclassed for the various certificate types, as the requirements
are slightly different.


%TOC%

---++ ObjectMethod *checkUsage* <tt>($valueObject,$usage) -> $errorString</tt>
Validates a Certificate item for the configure GUI
   * =$valueObject= - configure value object
   * =$usage= - Required use (email, client, server, clientserver)

Returns empty string if OK, error string with any errors