Am Mittwoch, 6. November 2013, 07:43:54 schrieb Theodore Ts'o: Hi Theodore, >On Wed, Nov 06, 2013 at 12:49:45PM +0100, Stephan Mueller wrote: >> Here is a quote from his answer to my question whether he was able to >> identify the root cause: >> >> "its inherent in the microtiming of Hardware and there is nothing you >> can do about it if you want the root cause is quantum physics" > >That's unfortunate, since it leaves open the question of whether this >jitter is something that could be at least somewhat predictable if you >had a lot more information about the internal works of the CPU or >not.... I do not understand that answer: I thought we are talking about the search of non-predictable noise sources. If you cannot predict the sequence even if you have the state of the CPU, that is what we are looking for, is it not? Besides, how on earth shall an attacker even gain knowledge about the state of the CPU or disable CPU mechanisms? Oh, I forgot, your NSA guy. But if he is able to do that, all discussions are moot because he simply disables any noise sources by flipping a bit, reads the memory that is used to hold the state of the RNG or just overwrites the memory locations where data is collected, because the general protection mechanisms offered by the kernel and the underlying hardware are broken. Also, does your answer mean you would disregard radioactive decay that is not predictable due to quantum physics and Heisenberg? Ciao Stephan -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
