NRF52840 FLASH PROTECTION WITH SDK 15.0.0

Question

Hello Everyone, 
 I am using NRF52840 development kit, I have compiled the code using SDK15.0.0. I am using soft device as well. I have to implement flash protection in my device so that any third party member can't read the firmware from device. I am a beginner for flash programming on Nordic devices. So actually don't know where to start. I read few tickets but I am confused about the process. I have to implement this flash protection for the DFU firmware as well. Can anyone help me guide on this? How to enable this protection? 
 1) Reading firmware should be disabled. 
 2) I should be able to erase and reprogram/write the firmware. 
 3) OTA update should not be blocked. OTA update should happen. 
 4) Want to protect firmware of DFU as well. 
 
 Thank you,

Sigurd · Accepted Answer

Hi, 
 You can call "nrfjprog --rbp ALL && nrfjprog --reset" to readback protect and reset the device (to latch the new configuration). This is the equivalent to writing to this register , and then do a reset. 
 In addition, you can build the bootloader with NRF_BL_DEBUG_PORT_DISABLE set to 1 in sdk_config.h, the bootloader will then check if approtect is enabled, and if not, enable it and reset. 
 4) Want to protect firmware of DFU as well.

DFU: To protect the target device against malicious attackers trying to impersonate the rightful sender of the firmware update, the init packet of the firmware package must be signed. But the package is not encrypted. See this post: https://devzone.nordicsemi.com/f/nordic-q-a/60249/official-encrypted-secure-dfu/

NRF52840 FLASH PROTECTION WITH SDK 15.0.0

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