Messages in this thread |  | | Date | Mon, 1 Oct 2001 16:43:54 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH][RFC] Allow net devices to contribute to /dev/random |
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Hi!
> > Here is my reasoning. I'd like to quote drivers/char/random.c: > > * add_interrupt_randomness() uses the inter-interrupt timing as random > > * inputs to the entropy pool. Note that not all interrupts are good > > * sources of randomness! For example, the timer interrupts is not a > > * good choice, because the periodicity of the interrupts is too > > * regular, and hence predictable to an attacker. Disk interrupts are > > * a better measure, since the timing of the disk interrupts are more > > * unpredictable. > > * > > * All of these routines try to estimate how many bits of randomness a > > * particular randomness source. They do this by keeping track of the > > * first and second order deltas of the event timings. > > Obviously the timer interrupt would be the worst idea ever. Its the > same value (HZ) on almost all versions of Linux (Alpha being on example > where it is not the same).
Actually, not quite. On 2.4.9 system, console kept interrupts disabled for so long that timer interrupt was pretty good source of randomness.
Pavel -- I'm pavel@ucw.cz. "In my country we have almost anarchy and I don't care." Panos Katsaloulis describing me w.r.t. patents at discuss@linmodems.org - 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/
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