> If services like Stripe accepted already-encrypted credit card numbers, couldn't someone just steal the already-encrypted credit card numbers and run them thr

> If services like Stripe accepted already-encrypted credit card numbers, couldn't someone just steal the already-encrypted credit card numbers and run them through Stripe? OK then encrypt the credit card number + merchant ID > Also, resting the security of the payment infrastructure on a single keypair (per network) seems a bit risky. You'd probably want a more sophisticated infrastructure which individually identifies players and allows for revocation, ala chip & pin. Then perhaps Mastercard could have a separate public/private key pair for each merchant. Although even a single key pair for each card network would still be better than the status quo, wouldn't it?