On Thu, Oct 04, 2012 at 03:32:35PM +0200, Christoph Anton Mitterer wrote: > > When seeding the kernels entropy cache (which is then ultimately used > for /dev/random), e.g. by (semi-)TRNGs like haveged[0], > audio-entropyd[1], Simtec’s Entropy Key[2] or friends... can one spoil > the randomness by that or is this impossible by design?
It is impossible by design. Or specifically, /dev/random was designed so that it can be world-writeable, and an attacker can feed in any kind of input he or she wants, and it will not allow the attacker to know anything more about the state of the entropy pool than he or she knew before they started mixing inputs in. There are comments that go into more detail about the design in drivers/char/random.c. Credit for the design goes to Colin Plumb, who designed RNG in the original PGP 2.x implementation, BTW. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/