Secure boot for vanilla linux

Hello,

For the past 10 years I installed vanilla x86 (32 or 64) on embedded PCs.

First I boot this PC with knoppix and install legacygrub with: install-grub.

Now I want to do the same but with secured boot.
Can I use legacy grub or should I use grub2 ?

If grub2 is mandatory, can I use knoppix to install it ?

Thank you in advance,
Zvika