MSO and multiple communities

[Clive Page]

On Tue, 6 Jul 2004, Roy Williams wrote:

> What is there in the real world? There are credit cards!

Roy et al

I was thinking of posting something on the banking analogy too.  Only I
thought of two slightly different aspects:

(1) You need an account to do most things at a bank branch, and to get an
account you need to authenticate yourself quite carefully the first time
(needs passport and utility bills in the UK now, typically). The main
exceptions are things like changing one currency for another:  here banks
don't care who you are, as they take a percentage of each transaction. In
a similar way we need to ensure that some VO services remain account-free,
e.g. reading non-proprietary data.

(2) Cashcards and ATMs are almost universal - it is rare to visit a
country where your plastic card can't get money from a hole in the wall
machine.  How: there is a world-wide cryptographic algorithm embedded in a
chip in the machine, with a self-destruct mechanism if anyone tampers with
it.  The encoding algorithm is known to many banks and allows them to
issue PINs.  So a combination of your digital certificate (= the magnetic
stripe of the card) and your password (=PIN entered on the keypad) are a
reasonable guarantee of your right to withdraw cash.  Not 100% foolproof,
but losses are a tiny fraction of the amounts transferred.

Note also that cash machines are designed to work off-line (though mostly
now they are permanently on-line) - similarly it would be nice if our
authentication mechanisms didn't all fail of some network links were
faulty.


-- 
Clive Page
Dept of Physics & Astronomy,
University of Leicester,
Leicester, LE1 7RH,  U.K.