Hanover  - Millions of cash cards and security access cards may now be unsafe, the Hanover-based c't magazine reported recently.

Experts have succeeded in cracking the encryption of the Radio Frequency Identification (RFID) chip used in a widely available card system.

Stored information was successfully read out and copied from chips in the Mifare Classic series, the report claims. Depending on the intended use for the card, this could potentially lead to personal data landing in the wrong hands.

"Cards with this chip are very widely used in places like Germany as well," says Christiane Ruetten from c't.

The access control systems for many companies, not to mention the German army, are also handled using this chip, the magazine reports.

One way to tell whether a card includes an RFID chip is to hold it against a very bright light source.

"You can see lines all the way around the chip. That is the antenna," Ruetten explains. RFID also frequently have no magnetic strip. Just which cards are part of the Mifare Classic, however, can only be determined using a special reading device. (dpa)