On Jul 22, 3:45 pm, asdf <inva...@invalid.invalid> wrote:
> On Tue, 22 Jul 2008 07:05:53 -0700 (PDT), goo...@woodall.me.uk wrote:
> >What would be really neat, (but almost certainly not possible using a
> >standard oyster card) would be to have "magic" cards that change their
> >number.
>
> >For example, a Sunday trip from Watford Junction to London with enough
> >zone 1 travel to pass the z1-2 cap is cheaper with two cards. - 3.00
> >each way from WJ->Euston plus 4-80 z1-2 cap. (Z1-8妫徢띉 cap is
> >12.60) In theory it's maybe possible for the card to tell where it's
> >being touched in or out before it reveals its serial number (at the
> >very least it could possibly start a corrupted transmission first
> >time). So rather than having to have two cards and remember which one
> >to use when, the card could handle all that logic for you.
>
> >(You can do even better if you touch out/in at willesden junction -
> >total journey cost 6.80 - but that requires you to take the slow
> >train. I can't see how any hack is going to be able to generate a
> >valid touch out. I can that a faked touch in might be possible.)
>
> What on earth would be the point in such an elaborate scheme?

That it's a potentially legal way to want to use a hacked card. All
the hack is doing is making sure you don't accidentally use the wrong
card at the wrong point.

If
> you've hacked the card then you can just add £100 (or whatever) of
> PAYG credit, for free, whenever you feel like it.
>
> Your card would probably be blacklisted during the nightly
> synchronisation of the readers with the central database, but it does
> give you an unlimited day's travel each day for £3 (or, if you can
> change the card's serial number, not even that).

I don't know how quickly the system can react but I'd expect the
system to be transmitting the card reported details back to the
central system. So there's a good chance of your card being disabled
before you even reach your destination if you try and use it on the
tube.

Tim.