Your iMac with Apple silicon provides the following security features to protect what’s on your computer and prevent unauthorized software apps from loading during startup:
Secure startup: Support for secure startup is turned on automatically. It’s designed to verify that the operating system software loaded on your computer at startup is authorized by Apple.
If your iMac doesn’t start up because it detects an untrusted component, it starts up from a secure recovery partition and automatically corrects issues if possible. To learn how to set security options, see Revive or restore a Mac with Apple silicon with Apple Configurator in the Apple Configurator User Guide.
Learn more. See the Apple Platform Security Guide.