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    SubjectRe: x86 MSRs - example program
    Matthias Urlichs wrote:
    > In, article <m0w1e9H-000AA6C@cerebro>,
    > (Marc Lehmann) writes:
    > > >> ON the other hand... security hole????? how????????
    > > >>
    > > >Cryptography. If you know exactly how long a given algorithm takes for
    > > >different inputs, you can sometimes infer clues about the secret key.
    > >
    > > gettimeofyday is always available, and in that scenario is just
    > > as good as rdtsc.
    > >
    > gettimeofday isn't nearly as accurate. While that's not an absolute
    > barrier, it raises the number of iterations required to get accurate data.

    A few random length busy loops are enough to protect against a Kocher
    attack. This is certainly not a reason to prevent ordinary users from
    access to high resolution timers.

    Best regards
    Joerg Pommnitz || Never attribute to malloc
    Mobile/Wireless |Dept UMRA | that which can be adequately
    T/L (919)254-6397|Office B502/E117 | explained by stupidity.

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