Citycard - security

The security against manipulation of the data stored on the card is guaranteed by a multi-stage security concept. Every terminal ciphers and deciphers all data that is written to, or readout from the chipcard, using an complex mathematical algorithm.

The stored data on the chip is always cryptographically secured. By the use of a special project-code, only cards are serviceable that are intended for the use with the corresponding terminal.

A MPC (Memory Protection Code) is used additionally, which secures the cards memory from forbidden write operations. After each valid terminal transaction, the chipcard gets a newly calculated MPC. Some memory areas of the card become irreversible write-protected with the initialisation of the chip. Consequently, the card number can not be manipulated anymore.