diff --git a/simplelogin/docker-compose.yml b/simplelogin/docker-compose.yml
index 941aafe..058288b 100644
--- a/simplelogin/docker-compose.yml
+++ b/simplelogin/docker-compose.yml
@@ -59,8 +59,8 @@ services:
     volumes:
       - ./data/sl:/sl
       - ./data/sl/upload:/code/static/upload
-      - ./data/dkim/dkim.key:/dkim.key
-      - ./data/dkim/dkim.pub.key:/dkim.pub.key
+      - ./data/dkim/dkim.key:/dkim.key:ro
+      - ./data/dkim/dkim.pub.key:/dkim.pub.key:ro
       - ./data/env/simplelogin.env:/code/.env
     env_file:
       - ./secrets/app/.env
@@ -83,8 +83,8 @@ services:
     volumes:
       - ./data/sl:/sl
       - ./data/sl/upload:/code/static/upload
-      - ./data/dkim/dkim.key:/dkim.key
-      - ./data/dkim/dkim.pub.key:/dkim.pub.key
+      - ./data/dkim/dkim.key:/dkim.key:ro
+      - ./data/dkim/dkim.pub.key:/dkim.pub.key:ro
       - ./data/env/simplelogin.env:/code/.env
     networks:
       - default
@@ -101,8 +101,8 @@ services:
     volumes:
       - ./data/sl:/sl
       - ./data/sl/upload:/code/static/upload
-      - ./data/dkim/dkim.key:/dkim.key
-      - ./data/dkim/dkim.pub.key:/dkim.pub.key
+      - ./data/dkim/dkim.key:/dkim.key:ro
+      - ./data/dkim/dkim.pub.key:/dkim.pub.key:ro
       - ./data/env/simplelogin.env:/code/.env
     networks:
       - default
@@ -117,8 +117,8 @@ services:
     volumes:
       - ./data/sl:/sl
       - ./data/sl/upload:/code/static/upload
-      - ./data/dkim/dkim.key:/dkim.key
-      - ./data/dkim/dkim.pub.key:/dkim.pub.key
+      - ./data/dkim/dkim.key:/dkim.key:ro
+      - ./data/dkim/dkim.pub.key:/dkim.pub.key:ro
       - ./data/env/simplelogin.env:/code/.env
     networks:
       - default
@@ -132,8 +132,8 @@ services:
     command: python init_app.py
     volumes:
       - ./data/sl:/sl
-      - ./data/dkim/dkim.key:/dkim.key
-      - ./data/dkim/dkim.pub.key:/dkim.pub.key
+      - ./data/dkim/dkim.key:/dkim.key:ro
+      - ./data/dkim/dkim.pub.key:/dkim.pub.key:ro
       - ./data/env/simplelogin.env:/code/.env
     networks:
       - default