diff --git a/app.php b/app.php
index d7a7bfc..45cd806 100644
--- a/app.php
+++ b/app.php
@@ -83,7 +83,11 @@ $f3->route('GET /signature',
         }
 
         if (!$f3->exists('PDF_STORAGE_ENCRYPTION')) {
-            $f3->set('PDF_STORAGE_ENCRYPTION', '');
+            if (CryptographyClass::isGpgInstalled() == true) {
+                $f3->set('PDF_STORAGE_ENCRYPTION', 'true');
+            } else {
+                $f3->set('PDF_STORAGE_ENCRYPTION', '');
+            }
         }
 
         $f3->set('activeTab', 'sign');
diff --git a/lib/cryptography.class.php b/lib/cryptography.class.php
index 7081f80..ce19de8 100644
--- a/lib/cryptography.class.php
+++ b/lib/cryptography.class.php
@@ -74,5 +74,17 @@ class CryptographyClass
 
             return implode('', $pieces);
         }
+
+    public static function isGpgInstalled() {
+        $output = null;
+        $returnCode = null;
+
+        exec('gpg --version', $output, $returnCode);
+
+        if ($returnCode == 0) {
+            return true;
+        }
+        return false;
+    }
 }
 ?>