> De-identification

> Re-identification

Wouldn't these two features address your concern? ChatGPT gets a generated unique ID that is still a consistent value for each card, just not the number itself. Then when the results are returned, that generated ID is turned back into the real card number.

This only becomes a problem when the de-identified data itself is needed to answer a question, like tell me how many Visa cards were used in these transactions by checking the card numbers.