Most people use identification cards just to prove who they are. You have a photo, person name, title, sometimes a number or company name. Once the photo is matched to a live person face the ID badges job is done and identification or authorization process is complete.
This is not always the case or simply the job doesn’t end there. Slim piece of PVC is expected to do more, to talk to an advanced computer system and act as encrypted access code. Such communication can be achieved a number of ways.
The oldest way of electronic communication using plastic cards is reading the data off of magnetic strip which runs across the longer edge of the card. Simple swipe allows for reading 3 tracks of data, each just couple of bytes long. Low capacity has been just fine for credit cards and driver’s licenses where up to 16 digits long numbers have to be stored yet insufficient for virtually any encryption. Higher storage could be achieved by making the strip wider or using rotating head for reading just as VHS standard but variable sweep speed prevents this from happening.
Magstripe cards come in two flavors, high and low coercivity (HiCo and LoCo for short). Coercivity is the amount of magnetic field power required to change encoded value on the carrier. HiCo cards are generally used for application where encoded information never changes and needs frequent reading while LoCo have been applied in the segment of often data changes as well as where price of the badges is a factor as LoCo manufacturing cost is lower when compared to HiCo.
Higher capacity needs in conjunction with cost reduction in material pushed technology towards another way of communication. Barcode scanned by a laser light device has number of advantages over magnetic stripe. 2D bars could store a lot more data allowing enough room for decent encryption levels and at the same time don’t take any wear from reading since there is no physical contact between card surface and the reader. Moreover lack of magnetic component significantly reduces the cost of material. Most of the states in the US gave up magstripe in favor of barcodes on driver’s license and identification cards. Still the barcode is not the only upgrade from the magnetic communication.
Implanting a semiconductor chip into the card is one of the ways to implement high data capacity, fast access and flexibility to change the content at the same time. Barcodes printed on a card can’t be changed while modifying data on a chip is fast and reliable. Chip cards disadvantages are high cost and limited lifespan hence the applications have been limited to banking and expensive national identification documents in handful of countries.
Proximity cards bring together the best of both worlds. Just like barcodes they could be read without physical contact with the reader and at the same time stored data could be edited. Unfortunately tags are expensive when compared to plain PVC cards hosting barcodes. Reason for that is prox cards work as wireless transmitters, they have an antenna and a coil inside which provides electric power when placed against electromagnetic field.