S/MIME: decode protected header

app/src/main/java/eu/faircode/email/FragmentMessages.java

@@ -8974,6 +8974,7 @@ public class FragmentMessages extends FragmentBase
                 MimeMessage imessage = new MimeMessage(isession, is);
                 MessageHelper helper = new MessageHelper(imessage, context);
                 MessageHelper.MessageParts parts = helper.getMessageParts();
+                String protect_subject = parts.getProtectedSubject();
 
                 // Write decrypted body
                 SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
@@ -8999,6 +9000,9 @@ public class FragmentMessages extends FragmentBase
                 try {
                     db.beginTransaction();
 
+                    if (protect_subject != null)
+                        db.message().setMessageSubject(message.id, protect_subject);
+
                     db.message().setMessageContent(message.id,
                             true,
                             message.language,