Im Studium

Technical information

The Mifare chip card belongs to the group of "intelligent memory chip cards". As a contactless card, it has established itself as a global quasi-standard.Communication between the card and the card reader takes place via radio transmission. This means that no contacts are visible on the card surface. This considerably reduces the susceptibility of the entire system (card, card reader) to interference. Contacts cannot become dirty and there are no mechanical components for contacting.

Format and structure

The format of the card corresponds to type ID-1 and is defined in ISO standard 7810 ("cheque card format").

 

• Length: 85.60 mm
• Width: 54.00 mm
• Thickness: 0.76 mm +/- 0.08 mm
• Radius of the corners: 3.18 mm +/- 0.30 mm

The card is composed of several layers of plastic. The chip is embedded between these layers and the antenna required for the wireless connection is always positioned at the edge of the card. 

The card surface is usually printed in two steps. In the first step, the basic design is applied using offset or screen printing. As part of the personalization process, the chip card is printed with personal data (name, student identification number, etc.) using a thermal transfer process.

The capacity is one KByte. The Mifare card has a strongly pre-structured architecture of 16 separate and independently usable sectors of the same and fixed size. Access authorizations can be assigned separately. A read key and a read/write key are assigned to each sector. This makes it possible to use the chip card multifunctionally.

The chip works with an anti-collision protocol. If several cards come close to a reader, the system selects an active card and puts all other cards on hold until the transaction with the active card has been completed.

Data organization

As with processor cards, the information for the different applications is kept separate. Files on the processor card can be compared with the sectors on the Mifare card. Here too, the information for the different applications is stored separately.

Access conditions

The Mifare card can only be accessed via circuits that have been developed exclusively for Mifare. The data stream from and to the card is secured via project, sector, card and session-specific encryption. 

Essentially, reading a sector with key A and writing it with key B is realized. The same applies to the exchange, which is also a specially supported data structure: reading and debiting is secured with key A, upgrading with key B.

Mifare chip security features

• Fast anti-collision protocol
• Individual access rights for each sector
• Individual keys for each sector
• Mutual authentication (card - user)
• Data encryption during transmission
• CRC checksum generation and transport code

Technical data