- Forum: iPhone
And there's no reason even to limit it to hex. Using 34 alpha numeric characters (eliminating I and O as too similar to one and zero), a 10 digit identifier would have over 2 quadrillion (2 x 1015) unique values. That's roughly 300,000 for each person currently on the planet. Add four more for the issuer and card typle, one or two for check digits, and you're back to the current 16 digits, even not counting the CVV code.