In our project we must have FOTA functionality, and we want to encrypt these updates
I'm trying to create an encrypted firmware image update for MCUBOOT with "blinky" and "smp_srv" samples. I'm sucessfully updated a signed image without encryption, but can't find any manual how to do create an encryped update. According to this description I understood, that I must encrypt FW packet only, but how should I do it: which tool, which commands, what is the sequence ..?
I tried adding CONFIG_MCUBOOT_EXTRA_IMGTOOL_ARGS="-E my_key_file" to prj.cfg, but all generated hex/bin files contain the same FW payload without encryption (checked with hex editor).
There is some info here about the encryption process, but sorry, it's still not obvious for me what I should do. Is there any step-by-step manual how to create encrypted FW images? Maybe an example project or something else?
Thank you in advance for any help