ShapeCPU was the first one that I know of (https://github.com/hcrypt-project/obliviousJ https://github.com/hcrypt-project/obliviousJ). I built one off the same

ShapeCPU was the first one that I know of (https://github.com/hcrypt-project/obliviousJ https://github.com/hcrypt-project/obliviousJ). I built one off the same infrastructure called hideCPU. If you can create AND/XOR/NAND/etc gates _and_ feed-back output into your input, you can create a CPU. https://github.com/mmastrac/oblivious-cpu https://github.com/mmastrac/oblivious-cpu My goal was more to build some open prior art in the space rather than actually build a viable FHE CPU, but there's no reason why you couldn't implement one of these on top of the FHE system. To answer some statements about FHE computing that come up over and over: - Yes, you can loop + perform control flow in a FHE-based computer - Yes, you can recurse in a FHE-based computer as long as you have enough emulated RAM/stack - Yes, you can store state in a FHE computer - No, you cannot determine if a FHE computer has reached a certain state (or halted) from the outside without decrypting the system (or at least a state bit) - Yes, you can emulate RAM in a FHE computer - Yes, you can emulate a HDD (well, rotating storage) in a certain FHE computer constructions