Subject: RE: Unsettled topics, Qualified Certificates.

From: Anders Rundgren <[email-masked]>
Date: Tue, 25 May 1999 17:35:59 +0200

Stefan,

<snip>
>Issue 2) Storage of maximum value per transaction.

>The directive requires that a certificate, if applicable, shall contain
>information about a maximum monetary amount per transaction that the
>certificate should support. 

My comment to this is that the EU directive seems to try to solve all business problems with
certificates.  This is IMO a bad idea and will only delay things.

Let's say that you open a door with a cert.  How can you possibly say how much value you have behind the door?

And what is the true value of a signed business contract?

For monetary transactions it is up to the relying party (the bank, the selling organization) to
set proper limits and to your organization as well.  To do this in a static certificate
(probably issued by a TTP) is lunacy.

>This could be done by defining a new extension (like the Germans already
>have done in their interoperability specifications), or alternatively just
>say that this shall be solved by a certificate policy, possibly in
>combination with a policy qualifier.

Certificate policy could specify liability but that does not have anything to do
with the sums you transact or protect.

>Arguments has been raised that Policy qualifiers are not suitable for
>automatic interpretation but that is not confirmed.

Of course you can have any number of optional items but if people start to
actually use them you will pretty soon run into severe problems.

So my advice is to put tons of OPTIONAL "crap" in QC-draft (to keep some people happy) but 
just IGNORE them in real implementations.  This is the proper (only) way to handle EU bureaucracy :-)  :-)

Anders Rundgren
http://www.mobilephones-tng.com

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From: Russ Housley <[email-masked]>
Date: Wed, 26 May 1999 15:55:48 -0400

In my view, maximum value per transaction is a good candidate for an
attribute certificate.

Russ

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From: Petra Gloeckner <[email-masked]>
Date: Thu, 27 May 1999 14:45:05 +0200

Hi Russ,

in general I like the idea of attribute certificates but they are 
quite difficult to handle.
How do you assure that the certificate holder will send the respective
attribute certificate along which contains the maximum value per 
transaction? He could only send his signature certificate or a totally
different attribute certificate and the recipient won't know that
there is another attribute certificate containing a maximum value per
transaction.

Petra

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From: Stephen Farrell <[email-masked]>
Date: Fri, 28 May 1999 10:50:14 +0100

Stefan,

> there is another attribute certificate containing a maximum value per

I don't want to get into deep discussion here but of course there
are interop problems which can arise with a server handling
transaction limits (e.g. a server which has handles
Sterling transactions has know what to do with a Euro limit,
which it mightn't). The use of ACs (in this case short-lived,
I'd guess) provides one way to implement limits (note that
I'm not saying this is the only, or the best, way, so lets
not have a big discussion on all the possibilities:-)

On the "how", side; one scheme is for the server can ask an AC 
issuer or search a repository for an AC "owned" by the 
certificate owner and which includes a transaction limit.

Regards,
Stephen.