Whilst you can't hash it like a password as you need to be able to transfer it onwards, modern systems make tokenisation possible, where you immediately pass th

Whilst you can't hash it like a password as you need to be able to transfer it onwards, modern systems make tokenisation possible, where you immediately pass the details to the card processor, don't store them at all, and get back a token that can be used for that transaction. https://squareup.com/gb/townsquare/what-does-tokenization-actually-mean https://squareup.com/gb/townsquare/what-does-tokenization-ac...