 Secure Boot Loader. So what is a secure boot loader? A secure boot is the first code running after reset. It mustn't be bypassed. The main role is to verify the application former before launching it. The secure boot has to be robust enough against attacks. Most commonly, secure boot loader relies on a public key stored in an immutable way so that it can verify the signature of the target application. The principle is the same as the authentication example we made previously, except that the authenticated code does not include the secure boot itself. Secure Boot Loader principle. First of all, the secure boot loader must be separated from the application. So there are two standalone software parts. And after reset, there should be a unique boot entry point to make sure that the boot loader code is always the first part of the code to run after reset. And the secure boot loader must be stored in the chip in an immutable way and protected against bypass attacks. One main responsibility of the secure boot loader code is to compute the digest of the target application and verify its signature using the public key, which is stored in the same secure boot loader area. The signature of the target application will be attached to the binary of the target application as part of its metadata. The secure boot loader will jump to the application only if the signature verification is successful. Thank you for watching.