[y4mi]

Aren't card PINs only 4 numbers long? That's almost 10k possible combinations I believe, pretty trivial to put together.

Checking which corresponds to what card is the hard step because you need access to an acquirer to my knowledge, and you'll lose that access quiet quickly if you attempt too many incorrect combinations.

[Reason077]

You can use more than 4 digits if you want a more secure PIN.

EMV (the card standard used by all modern chip/contactless cards) supports PINs between 4-12 digits in length.

[hoppla]

I have been wanting to try a 4< digit pin, but I expect payment terminals to go bonkers because they don’t accept it. Have any of you a card pin longer than 4?

[InCityDreams]

All pins in my country are 5 digits. Which can be annoying for four-d visitors (depends on the bank, and I've not heard of problems for a while).

[charles_f]

Damned, with 5 digits, the cost of storage alone is a deterant for a rainbow table