Intel is at least supposed to be using something like a "coin-flip" circuit, which has two stable states and can be forced one way or the other based on thermal

Intel is at least supposed to be using something like a "coin-flip" circuit, which has two stable states and can be forced one way or the other based on thermal noise: http://spectrum.ieee.org/computing/hardware/behind-intels-new-randomnumber-generator http://spectrum.ieee.org/computing/hardware/behind-intels-ne... That output stream may be biased, so it subsequently goes through a "whitening" stage based on AES. (One question I haven't seen an answer to: presuming all the hardware functions as described, would it be possible for a microcode update to change the output --- e.g., by whitening the output of the real-time clock instead of what I'm calling the coin-flip circuit?)