Implementing LUKS on an appliance with automated keys
A key point to keep at the forefront of your thought process in the implementation of any security factor in an appliance solution is your end-user experience. This book was created to help you and your team create a secure but usable embedded Linux system.
Depending on what your solution is and how it is utilized by the end-users, it is paramount to prevent the need for those end-users to have to enter keys every time a system is turned on. Firstly, that appliance may not even have a console or a keyboard attached. Secondly, forcing the end-user to manually enter such a key will ultimately result in them writing the key down on a note somewhere taped to the machine or elsewhere in clear view in the workplace. Making the end-user enter the key passphrases should be avoided if at all feasible.
Here’s an example screenshot of how you may be prompted for a passphrase before the boot sequence can continue:
