README.md: Add secure boot notes

README.md

@@ -57,4 +57,27 @@ cd 01_basic_module/
 bear --append --output ../.vscode/compile_commands.json -- make -C $LINUX_MODULES_FOLDER/build M=$PWD modules
 ```
 
-Search -I args and -D args
+Search -I args and -D args
+
+### Sign kernel module for testing with secure boot enabled
+
+Prerequisites: Own secure boot keys
+
+Secure boot keys can be found in :
+
+- Fedora : `/etc/pki/akmods/certs/`
+- With sbctl : `/var/lib/sbctl`
+
+```
+sign-file sha256 $SECUREBOOT_KEYS_PATH/private_key.priv $SECUREBOOT_KEYS_PATH/public_key.der <module_file>.ko
+```
+
+sign-file is in `/usr/src/kernels/$(uname -r)/scripts`
+
+Full example (run as root):
+
+1. Fedora
+
+```bash
+/usr/src/kernels/$(uname -r)/scripts/sign-file sha256 /etc/pki/akmods/private/private_key.priv /etc/pki/akmods/certs/public_key.der <module_file>.ko
+```