Thanks Ron.

I'll sleep easy tonight.

--
Russell Dawson
Excel Student

Please hit "Yes" if this post was helpful.


"Ron Rosenfeld" wrote:

On Sat, 17 Apr 2010 23:39:01 -0700, Russell Dawson
wrote:

That's fine. It tells you the format i.e. 9 or 12 digits and the 3-4-2
format is no secret. It couldn't be as all businesses have to display it in
invoices etc.

What it doesn't give is the series of calculations apparently used to create
what might appear to be a VAT number to anybody duped into accepting that
number, first by it's issue and then confirmed as being valid via the sites
you mentioned.

I suspect that the validation site would only be using the appropriate
calculation to validate the number as a possible VAT number because it passes
the arithmetical test rather than check if the number has been issued and
therefore a true VAT registration number.

I'd be interested to know why Rob needs to do this.

The Modulus 97 algorithm is not secret.

See http://sima.cat/nif.php

But I don't know if the new modulus 9755 algorithm, which is supposed to be
being implemented in GB this year to increase the range of allowable VAT
numbers, is secret or not. Certainly it can be obtained with a legitimate
business reason.
--ron
.