Some credit cards offer that service: you are registered with them, go to their site, get a one-use number with a charge limit you pick. You provide that to the

Some credit cards offer that service: you are registered with them, go to their site, get a one-use number with a charge limit you pick. You provide that to the merchant, the "card number" validates fine. In my corner, the banks have associated and offer a single site that covers American Express, MasterCard and VISA. (Site, in Portuguese, is here: https://www.mbnet.pt https://www.mbnet.pt )