# File lib/rack/protection/session_hijacking.rb, line 19
      def accepts?(env)
        session = session env
        key     = options[:tracking_key]
        if session.include? key
          session[key].all? { |k,v| v == encrypt(env[k]) }
        else
          session[key] = {}
          options[:track].each { |k| session[key][k] = encrypt(env[k]) }
        end
      end