create_check_auth_request (OpenID::Consumer::IdResHandler)

    # File lib/openid/consumer/idres.rb, line 242
          def create_check_auth_request
            signed_list = @message.get_arg(OPENID_NS, 'signed', NO_DEFAULT).split(',')

            # check that we got all the signed arguments
            signed_list.each {|k|
              @message.get_aliased_arg(k, NO_DEFAULT)
            }

            ca_message = @message.copy
            ca_message.set_arg(OPENID_NS, 'mode', 'check_authentication')

            return ca_message
          end