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    SubjectRe: /dev/random in 2.4.6
    On Mon, Aug 20, 2001 at 04:00:30PM +0000, David Wagner wrote:
    > I don't see why not. Apply this change, and use /dev/urandom.
    > You'll never block, and the outputs should be thoroughly unpredictable.
    > What's missing?

    Absolutely. And if /dev/urandom is not unpredictable, that means
    someone has broken SHA-1 in a pretty complete way, in which case it's
    very likely that most of the users of the randomness are completely
    screwed, since they probably depend on SHA-1 (or some other MAC which
    is probably in pretty major danger if someone has indeed managed to
    crack SHA-1).

    > (I don't see why so many people use /dev/random rather than /dev/urandom.
    > I harbor suspicions that this is a misunderstanding about the properties
    > of pseudorandom number generation.)

    Probably. /dev/random is probably appropriate when you're trying to
    get randomness for a long-term RSA/DSA key, but for session key
    generation which is what most server boxes will be doing, /dev/urandom
    will be just fine.

    Of course, then you have the crazies who are doing Monte Carlo
    simulations, and then send me mail asking why using /dev/urandom is so
    slow, and how can they the reseed /dev/urandom so they can get
    repeatable, measureable results on their Monte Carlo sinulations....

    - Ted
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