I would to implement my custom algorithm of scrambling in SoC of STB(set-top-box), I would to know how to do to implement it hardware side in SoC, if it have to be implement in ROM or in the design of transport demultiplexer/descrambler. I m taking as example the schema of SoX NXP CX24155-45SZ. thanks
What exactly SoC do you mean? The CX24155 SoC you're referring to is no longer manufactured, and there is no way to implement a custom algorithm within it.
Have a great day,
Artur