Arduino for STM32

Hi,

I have written codes on my developed platforms for years and would like to keep them secured. Does anybody know how to protect a code on the STM32? I need it to be editable by myself whenever it is necessary but nobody else can download and discover the written code.

Thanks for your help!

the codes are in your sources, in stm32 it is only the binaries.

But, I think anybody can make another board behave the same as the first one based on the binary they get. Am I right?
Can we do this by 'Option bytes'?