Messages in this thread |  | | | Date | Mon, 20 Aug 2001 12:02:03 +0200 | | From | Martin Dalecki <> | | Subject | Re: [PATCH] let Net Devices feed Entropy, updated (1/2) |
| |
Robert Love wrote: > > On 18 Aug 2001 22:36:00 -0500, Oliver Xymoron wrote: > > But your claim is there _is_ entropy. If you think there is, go ahead and > > use it. Via /dev/urandom. Yes, I know it's theoretically not secure, but > > then neither is what you're proposing. > > I am only continuing this because I want to explain... > > I claim there is entropy from what? The difference between interrupts > for net devices? Everyone agrees that there is. The issues is that an > external attacker could influence the interrupts to the net device, and > thus make some assumptions about the state. That is why this patch is > configurable. Do as you please. As I said, some people want it or need > it.
I think you are just wrong - nobody really needs this patch. /dev/random or /dev/urandom ar *both* anyway just complete overkill in terms of practical security. /dev/urandom is in esp silly, since it is providing a md5 hash implementation inside the kernel, which could be *compleatly* and entierly done inside user land.
> Again, /dev/urandom is just as "secure" as /dev/random. Its the same > pool. The same stuff. Except that /dev/random blocks when the entropy > count hits 0. > > Now, this count is purely theoretical, too. Its an estime of the amount > of entropy -- lack of determinability -- in the pool of bytes.
Wrong. Don't let you confuse yourself by the way the term entropy is used in the documentation of /dev/random - it's an abuse of the mathematical definition anyway. The more appriopriate term there would be: signal source variability estimate.
> Even when it reaches 0, since the pool is still unknown (only previous > output may be known) and the output is hashed, its still pretty much > undeterminable. But mathematically and theoretically, our entropy > estimate says it is not.
You mean - there is no known algorithm with polynomial time behaviour enabling us to calculate the next value of this function from the previous ones - Not more nor less - no pysics and entropy involved. If you assume this holds true it's mathematically entierly sufficient that a single only seed value is not known. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |