An addendum ...

Avoid signing up for "Verified by Visa" and the similar service that MasterCard offers ... doing so often shifts much of the liability for on-line transactions, including bogus ones, to the cardholder ...

Verified by Visa passcodes can potentially be stolen and thus doesn't prevent one from being victimized ... but worse, one in such a situation often has less legal recourse than they would have otherwise.

Carders seem to have little difficulty getting CVV codes and thus it's no stretch to believe they can likely get Verified by Visa passcodes, etc in bulk too ...

In short, for now, in my view, it's best to avoid Verified by Visa and similar security schemes offered by MasterCard.

Ron