use paypal to check user real identity

is it possible, after user join my websites, to validate their identity connecting a paypal account and check if the 开发者_StackOverflow社区credit card's name, surname, address match?

As Heandel said, this is not something you should want. However, an alternative is to do a $1 authorization using Express Checkout. Set PAYMENTREQUEST_0_PAYMENTACTION=Authorization, retrieve the token and redirect the user to agree to the $1 authorization charge. Once redirected back to your site, you'll have received a PayerID, which you can use to call GetExpressCheckoutDetails and retrieve some (definitely not all) information.
E.g. first name / last name and email address. In addition, you'll know he/she has a working funding source.

Once satisfied, you can call DoVoid to void the $1 authorization and the user will not be charged anything at all.

No, it's not possible. The precise goal of Paypal is avoiding this kind of information "leak".

People use Paypal because it allows them to pay WITHOUT communicating their name, surname, address, credit card number, etc, to third party websites.