Fix decryption of messages encoded with non-ascii charset (#5962)

CHANGELOG

@@ -7,6 +7,7 @@ CHANGELOG Roundcube Webmail
 - Fix invalid template loading on a message error in preview frame (#5941)
 - Fix bug where HTML messages could have been rendered empty on some systems (#5957)
 - Fix wording of "Mark previewed messages as read" to "Mark messages as read" (#5952)
+- Enigma: Fix decryption of messages encoded with non-ascii charset (#5962)
 
 RELEASE 1.3.1
 -------------

plugins/enigma/lib/enigma_engine.php

@@ -1196,6 +1196,11 @@ class enigma_engine
         }
         else {
             $body = $msg->get_part_body($part->mime_id, false);
+
+            // Convert charset to get rid of possible non-ascii characters (#5962)
+            if ($part->charset && stripos($part->charset, 'ASCII') === false) {
+                $body = rcube_charset::convert($body, $part->charset, 'US-ASCII');
+            }
         }
 
         return $body;