Binary Image protection

[pacoblackxx]

Posted on June 10, 2012 at 19:07

Hi there,

I would like to know if there is a way to protect your binary image in a stm32f device (with mpu). With protection i mean that i would like to secure the binary image that runs on the device from been stolen and used by someone else. Are there any resources/docs to begin with? Thanx

[frankmeyer9]

Posted on June 11, 2012 at 10:06

Yes, there is.

Look in the Flash programming manuals of the parts you would like to use, search for ''RDP'' and ''option byte''. For unknown reasons, it is in a separate manual, not in the Reference Manual.

[pacoblackxx]

Posted on June 11, 2012 at 12:24

Thanx,

If i understand it correctly, the RDP will not allow to have a bootloader for firmware upgration, right? I would like to have the capability of upgrading the firmware with a usb stick for example.

[frankmeyer9]

Posted on June 11, 2012 at 13:42

I did not study this part in detail, I use stm32 part only for my private projects, and don't burden me with this hassle.

But as I remember, you can set the protection level page-wise. Secondly, a flash mass erase is always possible. Thus, a bootloader is certainly possible to implement, but you might need to execute your USB bootloader from RAM when doing a full erase. All those side conditions are mentioned in the manuals. By the way, I know Cortex M3 parts of competitors that have an USB bootlader in ROM ...

[emalund]

Posted on June 11, 2012 at 17:49

<i>If i understand it correctly, the RDP will not allow to have a bootloader for firmware upgration, right</i>

don't bother much with this, but all chips I know of can be programmed after a TOTAL erase regardless of protection. Erik

[Tesla DeLorean]

Posted on June 11, 2012 at 18:00

The ROM boot loader has classically disable certain functions when ROP is enabled, it is also possible to disable ROP and get the device back to a raw state.

This will of course make updating it in the field difficult to achieve securely. The FLASH memory can be read by a device using ROP, so a cleverly conceived loader of your own should be able to update the application portion of your flash.

[alok472]

Posted on June 13, 2012 at 02:51

''If i understand it correctly, the RDP will not allow to have a bootloader for firmware upgration, right?''

If i see Flash IAP code, i see that only WriteProtection is disabled before upgrade. No action on Read Protection. How will hacker able to read the firmware if you have your specific code for IAP ?''I would like to have the capability of upgrading the firmware with a usb stick for example.'' If you mean USB-drive, then you need the USB Host functionality. There is an ST AN on this. IAP using the USB-Disk