diff --git a/README.md b/README.md
index 6ac3b9b..846ca3b 100644
--- a/README.md
+++ b/README.md
@@ -42,10 +42,8 @@ In this example, the folder `$(pwd)/.tiddlywiki` is used for the data.
 
 ## Authentication
 
-Default credentials are `user`:`wiki`.
-
-Simply provide the `USERNAME` and `PASSWORD` environment variables to
-customize.
+Authentication is disabled by default. To enable it, simply provide the
+`USERNAME` and `PASSWORD` environment variables.
 
 ## Other settings
 
diff --git a/init-and-run-wiki b/init-and-run-wiki
index dba6810..4231b02 100755
--- a/init-and-run-wiki
+++ b/init-and-run-wiki
@@ -18,5 +18,8 @@ fi
 
 
 # Start the tiddlywiki server
-
-exec /usr/bin/env node $NODEJS_V8_ARGS $tiddlywiki_script mywiki --listen host=0.0.0.0 port=8080 username="${USERNAME:-user}" password="${PASSWORD-wiki}" debug-level=${DEBUG_LEVEL-none}
+if [ -z "$USERNAME" ]; then
+    exec /usr/bin/env node $NODEJS_V8_ARGS $tiddlywiki_script mywiki --listen host=0.0.0.0 port=8080 debug-level=${DEBUG_LEVEL-none};
+else
+    exec /usr/bin/env node $NODEJS_V8_ARGS $tiddlywiki_script mywiki --listen host=0.0.0.0 port=8080 username="$USERNAME" password="${PASSWORD-wiki}" debug-level=${DEBUG_LEVEL-none};
+fi