[LINK] Kaching a Cash Register for CommBank?
Roger.Clarke at xamax.com.au
Wed Oct 26 20:27:45 AEDT 2011
>$quoted_author = "Roger Clarke" ;
>> [I haven't had time to wrap my mind around CommBank's announcement of
>> an NFC-based payment scheme for mobile phones, but it sounds like
>> another highly intensive consumer data-trail.]
At 10:57 AM +0200 26/10/11, Martin Barry wrote:
>Is there any other way to do electronic transactions?
>"Freeing" ourselves from carrying cash removes the ability to make the
>physical security trade off that gains almost complete anonymity because
>there is no longer a physical token that when exchanged transfers the stored
>value to someone else.
>If "stored value" is just some data then you need an audit trail to prove
>that the value exists.
'Excellent question!', as those skilled in the art of presentation say.
Ooh, deja vu all over again. It's *years* since I worked in this space.
I did a quick check of this 1995 document:
That identifies ECash, NetCash and Millicent.
Michael Pierce's 1996 comparison paper is still up!
Yes, such schemes include a banker.
No, the banker isn't an intermediary.
That is to say, the merchant doesn't need to (and, in a conformant
scheme, doesn't) pass any information about the transaction to the
banker - just the id of the coin used to make the payment. The
banker confirms or denies the validity of the coin, and cancels it.
The coin is cryptographically-protected, hopefully; although some
micro-payments schemes prefer to just 'wing it'.
Yes, the merchant knows (something about) the identity of the buyer;
and a frequent customer exposes a data-trail and hence profile to the
But the vast majority of people who value privacy prefer society to a
desert island. What they want is to minimise the exposure of their
There was a second article in Delimiter on the topic. (I posted it
to the privacy list, but figured it was getting marginal for link):
CBA's Kaching app raises privacy concerns
Wednesday, October 26, 2011 11:42
Roger Clarke http://www.rogerclarke.com/
Xamax Consultancy Pty Ltd 78 Sidaway St, Chapman ACT 2611 AUSTRALIA
Tel: +61 2 6288 1472, and 6288 6916
mailto:Roger.Clarke at xamax.com.au http://www.xamax.com.au/
Visiting Professor in the Cyberspace Law & Policy Centre Uni of NSW
Visiting Professor in Computer Science Australian National University
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