Chip cards also can process data on the card. This gives them the equivalent processing power of the original IBM-XT computer, albeit with slightly less memory capacity. These cards are used for a variety applications, especially those that have cryptography built in, which requires manipulation of large numbers. Thus, chip cards have been the main platform for cards that hold a secure digital identity. IC memory cards can hold up to 1-4 KB of data, but have no processor on the card with which to manipulate that data.
Memory cards are popular as high-security alternatives to mag stripe cards.
Optical Memory Cards. Optical memory cards look like a card with a piece of a CD glued on top - which is basically what they are. Optical memory cards can store up to 4 MB of data. But once written, the data cannot be changed or removed. Thus, this type of card is ideal for record keeping - for example medical files, driving records, or travel histories.