public PrivateKey getClearpassKey() throws GuacamoleException {
        return environment.getProperty(CASGuacamoleProperties.CAS_CLEARPASS_KEY);
    }
Returns the PrivateKey used to decrypt the credential object
sent encrypted by CAS, or null if no key is defined.

@return
    The PrivateKey used to decrypt the ClearPass
    credential returned by CAS.

@throws GuacamoleException
    If guacamole.properties cannot be parsed.
extensions/guacamole-auth-sso/modules/guacamole-auth-sso-cas/src/main/java/org/apache/guacamole/auth/cas/conf/ConfigurationService.java