Re: randomdev entropy gathering is really weak

[Warner Losh]

In message <[EMAIL PROTECTED]> Alexander Leidinger writes:
: systems which have a more or less precise clock attached (e.g. GPS or
: atomic clocks which sync the system clock via nptd)? And what are the
: numbers for this solution (for those people which are interested in
: numbers to be their own judge)?

I can tell you right now that the variation between GPS and a good
cesium clock is on the order of +- 25ns.  With nanosecond resolution,
this gives you about 5 bits.  The variation of the system clock when
synchronized to the GPS receiver is on the order of +-10us as measured
with a parallel port interrupt and a pps line from the gps receiver.
The pps interrupt is measured using a fast interrupt (we hacked ppc to
do fast interrupts for this), so the latency is fairly small and
fairly constant.

I don't have datasets that I can point people at, however.

Warner



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