Originally Posted by
straygaijin
What the UK reseller is asking you for is the last 3 digits which are printed on the signature strip on the back of your card. This is normal practise in UK when you are buying across the internet as it 'proves' you are in physical possession of the card.
I doubt this is it - this is standard practice in many countries. In the UK I have frequently been asked for an authorization code which has involved getting me on the phone with my credit card company and going through some additional security questions. Following this the card company authorizes the transaction.