Jonathan Silverlight wrote:
In message , P. Maxson
writes
"Andrew Gray" wrote in message
. ..
**snipped for brevity**

Here in Sacto the "convenient" gas stations ask for your zip code after
you swipe your plastic which I am OK with although it could be better.

That's part of the address verification system. There
are variable levels. It's use is, usually, at the
discretion of the merchant. Typical address verification
uses the digits in your street address and your zip code,
though you can do a partial check as well. This isn't
much of a check though as these numbers are not all that
secret, but it's one of those extra steps that makes it
just that slightly more difficult to commit credit card
fraud, so on the whole it's worth it.


I wish they'd thought of that over here (UK). Much more memorable than
some PIN. I suppose the problem is that we have a postcode made up of
letters and numbers, which you can't key into a till or keypad.

That's not much of a problem. Lot's of keypads can do
alphanumeric entry. For example, many states in the US
have license numbers which contain letters. Most of the
big and/or modern merchants have systems that work with
this. The biggest problem with this is that zip codes
are big and not too difficult to guess. Banks have
started to switch to newer systems such as CVV2, which is
more or less a hack of the address verification system
only using an individualized short numeric code.

However, there are limitations on how secure you can make
credit cards as they currently exist. The basic premises
of the credit card system, especially in terms of
information protection and client/merchant trust, are
outmoded and haven't scaled well to the way the use of
credit and debit cards has grown. Eventually it will need
to be replaced with a much more robust system devised with
modern technologies in data security and encryption in
mind, until then we just have to live with it.