Magnetic strip is the oldest and the cheapest holder of information which can be read automatically in card readers. Magnetic strip cards (ISO 7811) are usually used for creating systems with a large amount of cards where information holder is chosen based on existing technology infrastructure for reading the magnetic strip. In general, the readers can be found in most of institutions and service points. From the security point of view of the recorded data, a significant disadvantage of this type of card is the limitation for proper protection as the data recorded on a strip can quite easily be copied. In systems using magnetic strip cards all the important information should be recorded in the system computers and cards should be exclusively ID number carriers. Nowadays, the most popular are HICO (high coercivity) cards which are more resistant to demagnetization. The strip coercivity rate is high (approximately 4000 Oe) and data is recorded on three tracks: the first allows to record 75 alphanumerical digits, the second - 40 numerical digits, and the third - 107 numerical digits. On the market you can still find LOCO (low coercivity) cards which also include three tracks but low strip coercivity rate (approximately 350 Oe) and makes the cards more vulnerable to demagnetization.