diff --git a/src/Commands/Issue.php b/src/Commands/Issue.php
index 966db13..6c3f372 100644
--- a/src/Commands/Issue.php
+++ b/src/Commands/Issue.php
@@ -95,7 +95,7 @@ class Issue implements Command {
 
                 file_put_contents("{$path}/{$token}", $payload);
                 chown("{$path}/{$token}", $userInfo["uid"]);
-                chmod("{$path}/{$token}", 0660);
+                chmod("{$path}/{$token}", 0664);
 
                 yield $acme->selfVerify($domain, $token, $payload);
                 $this->logger->info("Successfully self-verified challenge.");
diff --git a/src/Commands/Register.php b/src/Commands/Register.php
index ce145ea..8ca0055 100644
--- a/src/Commands/Register.php
+++ b/src/Commands/Register.php
@@ -70,8 +70,7 @@ class Register implements Command {
             file_put_contents($pathPrivate, $keyPair->getPrivate());
             file_put_contents($pathPublic, $keyPair->getPublic());
 
-            chmod($pathPrivate, 600);
-            chmod($pathPrivate, 600);
+            chmod($pathPrivate, 0600);
         }
 
         $acme = new AcmeService(new AcmeClient($server, $keyPair), $keyPair);