Problem with faked-system-time option

[Robert J. Hansen]

On Wed, 15 Jun 2011 21:12:02 +0100, MFPA <expires2011 at ymail.com> wrote:
> Court proceedings tend to require evidence. The use of a timestamping
> service could provide this.

As soon as you're able to prove to a court that a timestamping service's
clock is fair and honest, sure.

But if you're able to prove that a timestamping service's clock is fair
and honest, then the original signer could use the same process to prove
*his* timestamp is fair and honest -- and thereby remove the need for a
timestamping service in the first place.

Your argument leads to a paradox.  If a timestamping service's clock can
be proven to be fair and honest, then there is no need for timestamping
services.

Timestamp authorities are *trusted* to be fair and honest -- but that's
not the same thing as *proven* to be, and nothing in the world is easier to
revoke than trust.