      def self.normalize_key_names(options)
        options = options.dup
        if options.key?(:key_prefix) && !options.key?(:namespace)
          options[:namespace] = options.delete(:key_prefix) # RailsSessionStore
        end
        options[:raw] = !options[:marshalling]
        options
      end
The application deserializes untrusted data without sufficiently verifying that the resulting data will be valid.