Re: x86 MSRs - example program

Matthias Urlichs (smurf@noris.de)
5 Mar 1997 15:27:46 +0100

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.

-- 
You are not permitted to kill a woman who has wronged you, but nothing
forbids you to reflect that she is growing older every minute.  You are
avenged fourteen hundred and forty times a day.
               --Bierce

-- 
Matthias Urlichs         \  noris network GmbH  /  Xlink-POP Nürnberg 
Schleiermacherstraße 12   \   Linux+Internet   /   EMail: urlichs@noris.de
90491 Nürnberg (Germany)   \    Consulting+Programming+Networking+etc'ing
   PGP: 1024/4F578875   1B 89 E2 1C 43 EA 80 44  15 D2 29 CF C6 C7 E0 DE
       Click <A HREF="http://info.noris.de/~smurf/finger">here</A>.    42