Giving vB Usergroups/Accounts Access Pasword-protected Files?

[PoC2]

Sorry if I've missed this elsewhere, but is there a way for a vB user to sign up to a subscription (say through PayPal via vB) and then for that user's account details to be used for access to a set of secure files.

I know the simplest way would be to just list the files in a secure forum with access via a paid subscription user group, but I'm looking for something that's not only automated but means that users can't access those files afterwards, even if they bookmark the file locations?

Any ideas?

Many thanks.

P.