How to thwart POS hackers

POS (point-of-sale) terminals are just one environment that has become increasingly more vulnerable to hacks. At the end of 2015 the Berlin-based company Security Research Labs showed just how easily the devices can be attacked. “Hackers can complete a physical attack without a great deal of effort,” confirmed Thomas Hess, Head of Sales and Project Management at Multiple Dimensions in Biel, Switzerland.

“Direct attacks on terminal hardware allow attackers to gain access to sensitive data, such as credit card numbers and PIN codes. “Private information is temporarily stored on the devices in order to prevent the loss of data if the internet connection is dropped during the payment transaction,” he explained.

3D-MID protective caps increase the security classification
Swiss company Multiple Dimensions is a specialist in the field of 3D-MIDs (Three-Dimensional Molded Interconnect Devices). This technology is based on injection-moulded plastic components, to which conductive traces are applied using the laser direct structuring (LDS) process. It is increasingly being used by manufacturers of POS terminals to improve security standards and fend off hacker attacks.

So how do injection-moulded plastic circuit substrates offer greater protection from physical attacks than conventional PCBs? “To gain access to hardware, most hackers either use probes or mini-drills. Our traces, which are located directly on the inside of the terminal’s protective cap, represent a closed-circuit and are positioned so closely to one another that it is more or less impossible for a hacker to gain access without damaging a trace,” continued Hess. If a trace is cracked, the entire circuit then fails – prompting the POS terminal to shut down immediately, whereby the cached data is lost and the device can no longer be used. The technology from Multiple Dimensions means that customers can benefit from compliance with the strictest PCI DSS requirements (Payment Card Industry Data Security Standard).

“The benefits of injection-moulded circuit substrates are extremely appealing,” commented Hess, describing the 3D-MID technology, adding that “they replace conventional solutions with a plastic carrier and PCBs by integrating the function of the two parts into one MID – thereby combining reduced weight, a smaller number of components and low production costs, while at the same time increasing security.”

The thermoplastic base material is first compounded with a (non-conductive) laser activated metal organic additive. The LDS laser beam structures the trace pattern onto the plastic by cleaving the metal organic additives while roughening and ablating the plastic precisely where the beam strikes the surface. Copper seeds split out from the additive, attracting free copper in the subsequent metallisation step.

The smallest trace space pitch in the market
Hess continued: “What sets us apart from the competition is our technological know-how in combination with worldwide competitive production, as highlighted by our uniquely small trace width and narrow spacing. The tighter the spacing between the individual traces, the more difficult the circuit is to manipulate from the outside. Most providers today offer trace width and spacing of around 300-400µm. However, Multiple Dimensions in Switzerland today produces traces with spacing of just 150µm. Our production environment is currently capable of creating traces with even tighter 80µm spacing. We are therefore in an excellent position to handle stricter security requirements – which we are definitely expecting to see in the near future.

“Thanks to our special technology, we can form three-dimensional parts and then process these using a laser. As such, even rounded edges are no longer a problem. Even raised sections and transitions, which can be a real challenge for basic PCBs, can be processed without any issues.”