Hy
Lets assume we run a C program on the FPGA. This program contains a loop which executes EXACTLY n times. How can I make sure that this value n isnt changed in the memory by an attacker? Is there something like temper resistant memory available? Or what other suggestions come into question?
Thanks for any comments
Markus
Your question doesn't seem to make a lot of sense - an FPGA is essentially a bunch of logic gates with configurable routing between them, whereas usually C is targeted towards a processor - a thing that takes a sequence of instructions and performs actions based on those instructions.
You can "run" a C program on an fpga in the following ways - a) By implementing a soft-processor in the FPGA. The C code is then not really "running" on the FPGA then, but on a processor that happens to be implemented in the FPGA. c) By converting what the C program is intended to do into a digital logic design and then loading that configuration into the FPGA. In that case, the "program" isn't really a program any more - it's a piece of digital logic.
Secondly - memory. An FPGA works by storing the configuration of the logic and routing in configuration memory cell. It may also have embedded RAM for use in datapaths. It may be interfaced to an external memory. You need to specify what type of memory you are talking about - this question could have many answers, and many dependancies.
If you are talking about memory as in physical configuration then if you have an unencrypted bitstream then an attacker could theoretically modify the bitstream. The capability to modify the bitstream could also be used to change any memory internal or external to the device. Some FPGAs have the capability to load encrypted bitstreams, and some don't.
Anything going out of the chip can be tampered with as well.
Jeremy
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.