Security Bit Feature

Hello everyone,

I would like to disable any possibility to read back the sketch stored in flash memory of Arduino Due.

Documentation of SAM3X (paragraph 9.1.3.5) speaks about "Security Bit Feature", which seems to answer my question?

On the other hand, "st3fan" posted such a question on dec.30 2012, and "aethaniel" answered it on jan.02 2013, but I must say that I did not understand a word of the answer...

If ever it is possible, could anybody explain to me the way to process?

Thank you very much in advance!

In fact, it seems that "bossac" utility is supported to perform such a task (option, "-s").
But "bossac" can only enter communication with Due if I fix baudrate to 1200... thus erasing flash!
Anyway, "bossac" is not present anymore in revison "1.6.3", even after donloading tools for Arduino Due through "board manager".
So I still cannot know if there is any possibility to protect sketch residing in flash memory, and I sincerely regret it...
Really nobody with any explaination?