FPGA bitstream protection with PUFs, obfuscation, and multi-boot

With the combination of PUFs, obfuscation, and multi-boot, we are able to do the equivalent of partial bitstream encryption on low-cost FPGAs, which is only featured on high-end FPGAs. Low-cost FPGAs do not even have built-in support for encrypted (full) bitstreams. Our particular PUF implementation does not steal valuable FPGA real estate from the actual design with the help of multi-boot. We favor multi-boot over self partial reconfiguration as it is easier to implement.