Nanjing IOT Sensor Technology Co.,Ltd

Bank Card Anti-skimming Solutions

ⅠBackground
Since ATMs have different models and shapes, it is difficult for ordinary cardholders to distinguish between normal card slots and exceptional ones. Therefore, they always fall into criminals’ traps and ATM crimes also keep increasing. Installing a skimmer on the card slot has become the most common form of ATM crimes. Although video surveillance systems have been installed on most ATMs, these can be only used for ex-post evidence collection and it does not have any effects on pre-warning and preventing crimes. Facing with complex ATM card using environment and due to inherent pitfalls of the video surveillance system itself, it can’t provide prompt and effective pre-warning and prevention.

The basic function of security system is to find crimes in time and prevent them, but the facts have proved again and again that single ATM video surveillance system can’t curb rampant bank card crimes effectively. The current situation has requested urgently that the ATM security field should turn traditional passive prevention into proactive security.

Ⅱ. Solution selection
Stealing bank card numbers and PINs to clone bank cards has become the modus operandi covering the largest proportion of ATM crimes. Other interferences, like posting false notes, are also used to clone bank cards. From technical level, cloning banks card needs two basic elements. One is bank card number (not printing card number on the card face) and the other is the PIN. Neither is dispensable. As long as one of them is protected, cloning risks can be eliminated. Since there are various kinds of methods to steal PINs, for example, installing video cameras or false PIN pads. It is difficult to take a unified technical preventative measure. Bank card number is the most basic element of cloning bank card and the only way to obtain it lies on the card slot (the card access system in self service banking has been canceled). Therefore, criminals all install password theft equipment on the card slot. From the perspective of pre-warning, the safety of the bank card can be guaranteed if the card slot is well-guarded.

Currently, a few solutions can be used to detect whether the card slot is exceptional (for example, installing skimmers and password theft equipment). Comparative analyses of different solutions are as follows:

1. Light judgment: utilize the infrared light reflection principle. Drill some holes around the card reader and the infrared light will be emitted through the holes form internal part of the self service equipment. When criminal installs the other device on the card reader, it will block some holes. In this way, it can judge whether there is an illegal device installed on the ATM.
The disadvantage of this method is that it must drill holes on the ATM, which will break the original structure of the ATM. In addition, if there are some exceptional objects (such as dusts) blocking the holes or the light environment changes, it will cause high false alarm rate. If the skimmer is installed bypass the holes, it will cause alarm omissions.
Therefore, this solution is not feasible in the actual use.

2. Electromagnetic field judgment: use the magnetic field strength sensor or electromagnetic field strong sensing device to detect the electricity and magnetic field changes around the ATM card reader and then compare the change situations to the normal ones. If any exception occurs, it indicates that there is a card theft device installed on the card reader.
This method uses short-range detection technology, which also needs to drill installation holes on the ATM and change ATM’s original structure. If the ATM has a metal shell, the detection device must be installed outside and thus it itself will become a potential safety hazard. Besides, theoretically speaking, as long as there is an object that can change magnetic field strength, there will be false alarms. If you turn down the detection sensitivity, it will cause alarm omissions, moreover, it is very difficult to grasp the scale of sensitivity adjusting.
Therefore, this solution is not feasible in the actual use, either.

3. Use image processing technology to analyze images on the ATM card reader and find out features. Compare the images to the ones on the original card reader and if there is an exception, it indicates that a skimmer is installed on the ATM.

This method is sensitive to environmental illuminance, which has high requirements on image definition. Once these conditions can’t be satisfied, it will bring about high false alarm rate. However, its most serious weakness is that the video camera used at current can only capture flat images which have no anti-counterfeiting function. If the installed skimmer has the same appearance and color as the original card reader, it is impossible to tell them apart from video images and thus serious alarm omissions will generate.

Since the existing surveillance video cameras all have the inherent features of flat images, so it is difficult to use flat image analysis to solve the recognition problem of skimmers and the actual results at home and abroad are not good, either.

Ⅲ. Features and advantage analysis of anti-skimming system based on laser ranging principle
All bank card password theft crimes have a common feature, which is to install skimmers on ATMs. Any installation means that physical thickness of some important parts (card slot, PIN pad) has been changed. Use high-precision laser ranging sensor to monitor the changes of spatial height of these sensitive parts in real time and thus it can judge whether there is a skimmer installed on the card slot. Moreover, it will raise the alarm, pre-warning and voice prompt as well as taking on-site pictures during the installation process and thus it can help prevent crimes in time and win more time for arresting criminals.