Restricting access to information on memory programming
Another simple trick many semiconductor manufacturers use is restricting access to information on memory programming. This is normally used for smartcards, but on some microcontrollers such information is not publicly available as well. This is not a reliable and practical way of making the design secure. Of course it works well with smartcards where all the customers are obliged to sign a non-disclosure agreement with the chip manufacturer. But microcontrollers, with very few exceptions, can be programmed with universal programmers that are widely available from different companies around the world. Even if the programming specification is not documented, all the necessary waveforms can be easily extracted in a few hours with using any low cost oscilloscope, because all the signals are normally applied with less than 1 MHz frequency. If the microcontroller is not supported by a particular universal programmer, it is always possible to buy the development kit directly from the manufacturer and obtain all the necessary protocols from it directly.