Howdy all,
Regarding "security", or better, unauthorized modification of the design ...
All chips I have worked on in the past use a jtag scan chain for (manufaturing) testing. The customer can run a similar scan on the final board or on the chips from the fab.
It would be quite difficult (but not impossible) to hide malicious code from the scan chain. Best case (for the hacker) would be that he hid his code but doesn't know if there are manufacturing defects in it or not.
Some people have obscure security blocks, that are based on noise generated by the circuit and they can detect the smallest deviation. I believe they monitor the power lines. I think these guys do something like that: www.eshard.com (no idea if it's patented etc.)
rudi =============================================================== Rudolf Usselmann, ASICS World Services, LTD, www.asics.ws Your IP Partner: SAS 12G, SATA-3, USB-3, SD/MMC/SDIO, FEC, etc.
The agony of poor quality remains long after the joy of low cost has been forgotten
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