Dear Richard Retanubun,
In message 4FFAE18D.3080809@ruggedcom.com you wrote:
Thus, we aim to add the ability uboot to identify users, much like the payload OS does before granting access to its CLI (if the user interrupts the boot process).
You are opening a can of worms here, and I bet you don't know yet how big it is. U-Boot has never been designed with any such level of security in mind.
If you want securityu, then add it to an environment which has been designed for it, i. e. use an OS like Linux. Use U-Boot just to boot this OS, and don't give anybody an easy chance to break in.
On the other hand, realize how complicated it is just to attach a JTAG debugger and take over full controll of your board. Yes, even if you don't provide a connector to such an interface. I know quite a number of systems that have been "opened" this way.
Frankly, I doubt this makes sense from a technical point of view. [Yes, I know that there are situations where management and.or marketing asks for such stuff. But is that a good reason to do it?]
Best regards,
Wolfgang Denk