lkml.org 
[lkml]   [1997]   [Mar]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: x86 MSRs - example program
    Matthias Urlichs wrote:
    >
    > In linux.dev.kernel, article <m0w1e9H-000AA6C@cerebro>,
    > mlehmann@hildesheim.sgh-net.de (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
    --
    Joerg Pommnitz |Joerg@Raleigh.ibm.com| Never attribute to malloc
    Mobile/Wireless |Dept UMRA | that which can be adequately
    T/L (919)254-6397|Office B502/E117 | explained by stupidity.

    \
     
     \ /
      Last update: 2005-03-22 13:39    [W:0.018 / U:35.812 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site