Mifare

MIFARE NXP Semiconductors is the world's most widely used contactless smart card technology. According to the manufacturer a total of over 5 billion cards and 100 million card readers have been sold so far. It complies with the ISO standards ISO 7816 and ISO 14443. MIFARE chips are also manufactured by Infineon Technologies.

Technology

MIFARE transponder operates at a distance of up to 10 cm and uses a frequency of 13.56 MHz.

The MIFARE card does not need a battery and is powered by the oscillating magnetic field of the base station ( write device ) with energy. Here, an integrated into the transponder wire coil when passing through the magnetic field on the power required. Modulates or demodulates the transponder, the excitation field of the base station ( write device ) to communicate.

The memory of the MIFARE Classic card is divided into several sectors, which are protected independently from unauthorized reading or writing. The sectors are in turn divided into a plurality of blocks, each of 16 bytes. The last block in each sector is called the Sector Trailer and includes two keys ( authorization levels ) as well as the associated access rights (Access Conditions) for the sector concerned. This mechanism allows, with a MIFARE transponder to use several different applications ( " multi-application ").

History

MIFARE was developed in the 1990s by the Mikron Society for Integrated Microelectronics in Gratkorn. The Mikron GmbH was acquired by Philips Semiconductors in 1995 and is therefore now part of NXP. MIFARE is an acronym for Mikron Fare Collection System (microns fare system ), since the technique was originally used for contactless buying tickets in public transport. MIFARE has helped shape the market for contactless smart cards without their own power supply significantly.

Areas of application

  • Will use the chip, for example, in student cards, where he serves as a cashless means of payment for the Mensa et al.
  • Various access control systems and time attendance systems use eg MIFARE Classic or MIFARE DESFire EV1.
  • Release print jobs to printers and multifunction devices

Encryption system

The encryption of the MIFARE Classic chips often used is based on a proprietary stream cipher called Crypto -1. This algorithm could be reconstructed by researchers at the Chaos Computer Club and the University of Virginia ( by so-called " reverse engineering ").

As announced on 13 April 2008 a group of researchers has analyzed the algorithm and found a systematic error that makes the encryption virtually useless. The security of the algorithm, concluded the researchers, is " close to zero ".

The Chaos Communication Congress is an easy way was shown how the encryption is crackable by a simple reversal with a mathematics program.

Protection options

There are quite some time ways to protect MIFARE transponder in a variety of styles from unauthorized access:

  • Shielding casings, in which the transponder is inserted
  • Stickers for cards and envelopes which prevent Feldabsorbtion means a communication

Follow-on products and variants

Besides the original MIFARE card, which is referred to according to current NXP terminology as " MIFARE Classic", there are now a large number of further developments, with current encryption algorithms ( 3DES, AES) work. Even the original sector-based access system was extended by the introduction of a multi-application system on MIFARE DESFire cards. The following versions are available today:

ISO/IEC 14443 Data Encryption Standard Advanced Encryption Standard
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