# File lib/openid/server.rb, line 177
      def answer(signatory)
        is_valid = signatory.verify(@assoc_handle, @sig, @signed)
        signatory.invalidate(assoc_handle, true)

        response = OpenIDResponse.new(self)
        response.fields['is_valid'] = is_valid ? 'true' : 'false'
        
        if @invalidate_handle
          assoc = signatory.get_association(@invalidate_handle, false)
          unless assoc
            response.fields['invalidate_handle'] = @invalidate_handle
          end          
        end

        return response
      end