Secure Boot is a component of Microsoft that relies on the UEFI ((Unified Extensible Firmware Interface) specification’s secure boot functionality to help prevent malicious software applications and “unauthorized” operating systems from loading during the system start-up process.
So How It’s Works?
Well,In the previous versions of windows,Microsoft never introduce anything like Secure Boot.It is a very good way to prevent malicious programs and unauthorized operating system to affect your computer.
Every Operating System that is authorized by Microsoft can run on a system where Windows 8 and later versions already installed.If a machine has Windows 8 or 10 already installed you can not install any other software or OS during boot time which is not authorized by Microsoft.
How Microsoft Give permissions to load other OS in Boot Time?
Well,Microsoft provide license for this.If any company or OS company want to run there OS with the Windows they have to purchase a licence.
For example You can Run Ubuntu or Linux Mint very easily.Because they have license But Kali Linux or any other security testing tool can not run on windows 10.