Authenticate users using simpleSAMLphp
wp-content/plugins/directory of your WordPress installation.
Log in as administrator and activate the plugin. Go to the Options tab and configure the plugin. If applicable, configure an eduPersonEntitlement that will be mapped to the Administrator role. Decide which attribute to use for the username. Take into consideration that the
sanatize_user() function will be called on the value of this attribute (see
wp_includes/formatting.php) which will remove anything but lowercase alphanumeric, space, dot, dash, and @-sign, and truncate it to 60 characters. A check is done to prevent creation of accounts with wrong usernames.
If the attribute you intend to use as username does have illegal characters, or is longer, you can work around this by using a hash of the username. Configure an extra attribute in simpleSAMLphp, for instance by applying an authproc filter like this:
25 => array( 'class' => 'core:PHP', 'code' => '$attributes["wp_userid"] = array(hash("sha224", $attributes["id_with_slashes"]));', ),
wp_userid as the username attribute. Now STAY LOGGED IN to your original administrator account. You won't be able to log back in once you log out.