How can I set HCI bluetooth device as auto security mode with default pin code when matching with on...

I want to set hci bluetooth device as “security none” without pin code or “security auto” with default pin code, when matching with an Android phone. I have attempted to configure file “main.conf”, but it does not work.

My Linux OS: Ubuntu16.04
Bluez version: 5.37.

So, can you please tell me something about how set “security manager mode” of hci bluetooth? Thinks a lot!