Magnetic Stripe

A magnetic stripe card is a type of card capable of storing data by modifying the magnetism of tiny iron-based magnetic particles on a band of magnetic material on the card. The magnetic stripe, sometimes called a magstripe, is read by physical contact and swiping past a reading head .Magnetic stripe cards are commonly used in credit card, ATM Card, indetity card, and transportation tickets

There a two type of magnetic stripe variety. One is High coercivity and other low coercivity. Diferent both that tyape is, High coercivity have strong magnetism and hard to erase data , right for card which have frequently use. For Low coercivity againts from High Coevercity.

Ussualy, we can recognize the coercivity from color of magnetic stripe. If the color of magnetic stripe is light brown it means the magnetic stripe is have low coervicity, but if dark brown the coercivity is High coercivitym, but now high coercivity have Silver colour.

On the inside, magnetic stripe consist 3 track for each magnetic stripe have own format to encode data to magnetic stripe. For financial such as ATM or Debit Card, ussualy only using track 1 and track 2, which the format following ISO 7813 (international standard for financial Card).
The information on track 1 have many format, but financial instution using format B for encode track 1, the format track 1 is below :
Track one, Format B:
• Start sentinel — one character (generally '%')
• Format code="B" — one character (alpha only)
• Primary account number (PAN) — up to 19 characters. Usually, but not always, matches the credit card number printed on the front of the card.
• Field Separator — one character (generally '^')
• Name — two to 26 characters
• Field Separator — one character (generally '^')
• Expiration date — four characters in the form YYMM.
• Service code — three characters
• Discretionary data — may include Pin Verification Key Indicator (PVKI, 1 character), Pin Verification Value (PVV, 4 characters), Card Verification Value or Card Verification Code (CVV or CVK, 3 characters)
• End sentinel — one character (generally '?')
• Longitudinal redundancy check (LRC) — one character
Commonly the bank use track 1 with format B only for store name of customer, so if you on ATM and your name displayed on screen, you will know the name came from track 1 on your card.

For Track 2 was develop by banking industry(ABA). And track 2 format as follow:

• Start sentinel — one character (generally ';')
• Primary account number (PAN) — up to 19 characters. Usually, but not always, matches the credit card number printed on the front of the card.
• Separator — one char (generally '=')
• Expiration date — four characters in the form YYMM.
• Service code — three characters
• Discretionary data — as in track one
• End sentinel — one character (generally '?')
• LRC — one character
The ATM will acquire Primary Account number of customer from this track before sending to the network.