What is the easy way to implement secure serial DFU on host side for nRF52832 updating

[Fema]

My target is porting my host MCU (STM32) to update my NRF52832 code through the serial.

I test it on SDK14.2.0 and  PCA10040 , the secure_dfu_serial example is working , i can update through "nrfutil  dfu serail ....." command.

After i took a searching in this forum i still can't find a good solution to implement the code on STM32 MCU side.

Currently , the most easy way i know is to send the ini package and the binary file only to the NRF52832 .

But it is still not easy for me , there are some interaction between the STM32 and NRF52832 during these process i need to take care.

How can i do , trace the code and do the same job on the STM32 side ,

Is there any example i can refer ?

Thanks 

[lesher]

Port the python code from: https://github.com/NordicSemiconductor/pc-nrfutil. It follows the sequence diagrams here: https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v14.2.0/lib_dfu_transport_serial.html?cp=4_0_1_3_5_2_3_1#lib_dfu_transport_serial_msc