U-boot

Hello, dear U-boot team

I have question about your old feature: U-boot patch for adding of the public key to dtb file. https://patchwork.ozlabs.org/project/uboot/patch/1363650725-30459-37-git-sen...

I can’t understand, can we work only with public key? Why do we need to have private key for adding step? In documentation it is not very clear for me.

Thanks a lot.