=== modified file 'lisp/emacs-lisp/package.el'
--- lisp/emacs-lisp/package.el	2014-09-03 04:21:40 +0000
+++ lisp/emacs-lisp/package.el	2014-09-30 00:04:22 +0000
@@ -842,8 +842,9 @@
                          (epg-context-result-for context 'verify)))
         good-signatures))))
 
-(defun package-install-from-archive (pkg-desc)
-  "Download and install a tar package."
+(defun package-install-from-archive (pkg-desc &optional just-verify)
+  "Download and install a tar package.
+When JUST-VERIFY is set, only verify the signature."
   (let* ((location (package-archive-base pkg-desc))
 	 (file (concat (package-desc-full-name pkg-desc)
 		       (package-desc-suffix pkg-desc)))
@@ -858,7 +859,9 @@
 	    (unless (eq package-check-signature 'allow-unsigned)
 	      (error "Unsigned package: `%s'"
 		     (package-desc-name pkg-desc)))))
-      (package-unpack pkg-desc))
+      ;; do the actual install
+      (unless just-verify
+        (package-unpack pkg-desc)))
     ;; Here the package has been installed successfully, mark it as
     ;; signed if appropriate.
     (when good-signatures
@@ -1432,6 +1435,11 @@
            (package-make-button
             "Install"
             'action 'package-install-button-action
+            'package-desc desc)
+	   (insert " ")
+           (package-make-button
+            "Verify signature"
+            'action 'package-verify-button-action
             'package-desc desc))
 	  (t (insert (capitalize status) ".")))
     (insert "\n")
@@ -1546,6 +1554,13 @@
       (revert-buffer nil t)
       (goto-char (point-min)))))
 
+(defun package-verify-button-action (button)
+  (let ((pkg-desc (button-get button 'package-desc)))
+    (with-demoted-errors
+        (package-install-from-archive pkg-desc t) ; just verify
+      ;; note errors will preempt the following
+      (message "Package was verified"))))
+
 (defun package-keyword-button-action (button)
   (let ((pkg-keyword (button-get button 'package-keyword)))
     (package-show-package-list t (list pkg-keyword))))