I travel internationally often, and always get foreign charges that were not mine, after I returned. I have, with a great deal of trouble and effort, identified all of these fraudulent charges, whether successful or not (well, maybe). Notifying all the merchants using the monthly "Auto" is truly a pain, especially if you overlook one. I have grown to embrace the "Apple Pay" product, using my iPhone or Apple Watch. With this, the merchant does not know, or store, your card number, security code or name. Each transaction has a "One Time" code unusable to a hacker. Almost every merchant has this to use - except Walmart. It is universally available overseas. You load your credit cards into your phone and Apple Pay uses the one you select for the transaction. Certainly worth looking into -