You do realize not every locality has vat. Are you looking for a tax_exemption_id for a specific locality?
My shop is based in UK with vendors in UK and Europe here it is required to report tax information to the taxman when sellers reach the VAT threshold on a year basis. in EU, UK and some other eurozone country, a marketplace must have sellers adding their tax information (Tax ID) to their shop / admin panel to be able able to lawfully continue selling on the said marketplace.
So I am merely looking for a way to have in
dashboard > edit profile > user profile
Added sections where they can add such information
for instance :
Business type :
-Individual OR Sole proprietor ?
-Incorporated business ?
VAT ID (if apply)
VAT ID number :
Out of the box cs-cart has not even dedicated vat field..
Be happy to build you an addon that will track sales by vendor and collect the taxid/seller_type and then generate you a report (CSV) that lists total sales by vendor and their taxid for all or selected seller_type.
As far as your original post related to encryption, this too is possible with an addon to encrypt upon save and to decrypt upon get. Be best to use a separate encryption key than the standard key hardwired into config.local.php.
Both of these could be created in the same addon. Feel free to click the get-a-quote link in my signature and we can discuss your needs and I'll give you a quote.