error in process filter: Unsigned file ‘archive-contents’ at h\ ttp://orgmode.org/elpa/ code example

Example: error in process filter: Unsigned file ‘archive-contents’ at h\ ttp://orgmode.org/elpa/

;; -*- emacs-lisp -*-
(package-initialize)                ;; Initialize & Install Package
;; (setq org-...)                   ;; Your custom settings