Have you ever noticed a black magnetic stripe at the backside of our credit card? A number of thoughts run through your mind. For what purpose magnetic stripe is used? What information this stripe contains? Is the information only being read or the encoded information is copied? And, if information is saved, what could be the consequences? A thought like this inspire us to take a closer look at the card technologies and the family to which they belong- Automatic Identification and Data Capture technologies (AIDC). Answers to all these above mentioned questions are simple. The purpose for using magnetic stripe technology and in general, AIDC technologies, is to identify people or objects through machine automated process.