Linux Secure Boot

Secure Boot is a security standard designed to ensure that a device boots using only software that is trusted by the Original Equipment Manufacturer (OEM). It helps prevent unauthorized firmware, operating systems, or applications from running during the boot process.

• **UEFI**: Unified Extensible Firmware Interface, a modern replacement for BIOS that supports Secure Boot.
• **Public Key Infrastructure (PKI)**: A system that uses key pairs for verification, ensuring software authenticity.
• **Boot Loader**: Software responsible for loading the operating system, which must be signed to be trusted.

The Secure Boot process involves the following steps:

graph TD;
    A[Start] --> B[Check Firmware]
    B --> C{Is Firmware trusted?}
    C -- Yes --> D[Load Boot Loader]
    C -- No --> E[Block Boot]
    D --> F{Is Boot Loader signed?}
    F -- Yes --> G[Load OS]
    F -- No --> H[Block Boot]
    H --> I[End]
    E --> I
    G --> I
            

1. Enter the UEFI firmware settings (usually by pressing F2, F10, or DEL during boot).
2. Navigate to the Boot or Security tab.
3. Locate the Secure Boot option and enable it.
4. Save changes and exit the UEFI setup.
5. Install a compatible Linux distribution that supports Secure Boot.

• Maintain a backup of your keys and configurations.
• Regularly review and audit the boot process to detect any unauthorized changes.
• Use signed kernel modules and drivers to ensure integrity.