Magnetic stripe card

A magnetic strip is a strip which is coated with a magnetic metal oxide.

Typically, a magnetic strip on the back of a card (eg debit or credit card), the data to be electronically read by a swipe.

Technology

For magnetic stripe there are two different variants. These are designated with HiCo (High Coercivity ) and LoCo (low coercivity ). They differ in the magnetic flux density, with which they can be described:

By comparison, the Earth's magnetic field is in Germany about 50 μT = 0.05 mT strong.

Construction

Is customary, the structure of the magnetic strip according to the ISO standard 7811th According to this standard, the magnetic stripe has a storage capacity of approximately 1024 bits to three lanes. Lanes 1 and 2 are only specified for the read operation on the track 3 data can be read and written.

  • Lane 1: 76 usable characters (alphanumeric 7 bits / character )
  • Lane 2: 37 usable characters (numeric 5 bits / character )
  • Lane 3: 104 usable characters (numeric 5 bits / character )

Magnetic card readers

Readers can for simple applications, similar to the barcode reader, simply grind to a PC keyboard and then read the data. When encoding (method for storing ) is biphase-mark code (aka two- frequency coherent phase ) was chosen. A "normal " writing with zeros and ones is not possible as a magnetization in describing only by change of level, but not by constant level. In addition, a " Drag " with variable speeds must be possible. There are both " swipe readers " and " space Readers ". The difference is that with swipe readers the magnetic coding in place readers the magnetic field is used.

If the magnetic stripe is accidentally deleted, it can be read still some with a square reader.

Areas of application

Magnetic stripe cards are used in combination with PIN automatic identification of authorized persons. In addition, complementary data can be written to the card, for example, faulty insertions that may be read later.

Originally, the magnetic stripe cards are designed for use in banking. Due to the lack of safety, the application area, however, has now changed dramatically. Magnetic cards are today predominantly in use:

  • Admission control at concerts,
  • In hotels as key replacement,
  • In car parks,
  • For companies to work time and attendance,
  • As customer card / loyalty card,
  • Than gift card

And as a combination with embedded chips ( health insurance card, bank card ).

An advantage of the magnetic stripe card with respect to the chip card is the cheaper preparation. Thus, the areas of application are not limited to, the repeated use, but also for one-time use, the magnetic stripe card ( then with paper as a carrier ) practical. So it can be used in car parks, swimming pools, etc..

PIN storage

The PIN a debit card is no longer stored on the magnetic strip. In the past, the PIN was as a hash value from the account number, bank code, account of a sequence number and a secret PIN derivation key in the map, so that the correct PIN has been calculated at each transaction in the ATM and compared with the entered PIN.

Today, the PIN is not compared in ATMs, but cryptographically secured and transferred to the data center connected with each transaction. There PIN or her control data is checked. This is done, inter alia, by means of the above-mentioned PIN derivation keys, or more precisely: PIN verify keys. Testing in ATM, so offline and without data center is no longer permitted, as these keys can no longer be stored on the machine.

History

Magnetic strips were applied to magnetic card accounts in the early 1970s. These accounts were cards with special accounting machines used, the so-called magnetic accounts computers. On a magnetic strip on the back of the magnetic card account data from the last posting was stored on the front were printed all bookings in plain text.

  • Hardware
  • Identification technology
  • Storage medium
Electronic Cash Channel code Biphase-Mark-Code Loyalty program
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