[lkml]   [2003]   [Aug]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [RFC][PATCH] Make cryptoapi non-optional?
    Val Henson  wrote:
    >If entropy(x) == entropy(y), then:
    >entropy(x) >= entropy(x xor y)
    >entropy(y) >= entropy(x xor y)

    No, that's still wrong. Please see my earlier email with a counterexample.
    That counterexample disproves not only the earlier claim, but also this more
    recent revised claim.

    Let x and y be two 80-bit strings. Assume that x is either 0 or 1
    (equal probability for both possibilities). Assume y is either 0 or 2
    (equal probability for both possibilities), and is independent of x. Then
    entropy(x) = 1 bit
    entropy(y) = 1 bit
    entropy(x xor y) = 2 bits

    Again, I believe there is little basis to distinguish between taking the
    first half of SHA vs. xor-ing both the halves of SHA. One can come up with
    scenarios where one or the other is better, but there is little basis for
    believing that one of those scenarios is especially more likely than the

    In short, we're arguing about how many angels can fit on a pinhead.
    There are far better things to be worrying about.
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2005-03-22 13:47    [W:0.030 / U:62.336 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site