Card technology


At present, the Mifarechip is the only chip used in the cards enabling all of the card's main functions. The most important features of the Mifarechip are:

Data transmissioncontactless (by radio)
Frequency13,56 MHz
Transmission speed read/write2,5 µs / 25 µs
Transaction timesless than 100 ms
Radio rangeup to 10 cm
Memory16 memory blocks of 16 bytes each
Lifetime100,000 times rewritable, data retains up to 10 years

The most important security features of the Mifarechip are:

  • Individual access rights for each data block
  • Individual keys for each block
  • Data encryption during transmission
  • Transport code

The data stored on the Mifarechip

The Mifarechip consists of 16 memory blocks with a storage capacity of 16 bytes each. The data are located in 'chip drawers' which are sealed off from each other. The operators of individual services (e.g. cashless payment in the Mensa) only have access to the corresponding "chip drawer". Access is secured by secret keys.

System data

  • System data (manufacturer code, ...)
  • Card number

Application-independent data

  • Validity from
  • Validity until
  • University number of Saarland University
  • Code identifying the different groups of people at Saarland University (PKZ)
  • Card issuing organization
  • ID number (i.e. student registration number or personnel number)
  • Matriculation number or personal number
  • Card sequence number: all cards are numbered automatically and sequentially, allows identification when a replacement card is issued

Application block 'Electronic wallet'

  • The anonymous electronic wallet function is not linked to a bank account (in principle, it works similar to a classical copy card).