Wondering whether the $50 Armani suit you bought in that alley in Hong Kong is the genuine article? Soon, there may be a definitive way of knowing. A new system has been developed, in which designer-specific invisible patterns can be woven into fabric.

Prof. Christian Müller, at Sweden’s Chalmers University of Technology, started by applying a special dye to a polyethylene thread. The dye absorbs visible light, but can be seen using a polarizing filter. The idea is that each designer would have their own unique pattern that would be woven into their garments, that people such as customs officials could see using simple equipment.

That’s all very well and good, but what would stop counterfeiters from just reading and then copying those patterns? A number of different types of the dye can be used, and they can be bonded not only to polyethylene, but also to a variety of other synthetic and natural fibers. Depending on the specific combination of dye and fiber types, the optical spectrum of the pattern is different. Unless the counterfeiters knew the secret combination used, they wouldn’t be able to copy the exact look of an existing pattern – it’s not unlike the technology presently used on some banknotes.

According to Müller, it would be relatively easy and inexpensive for clothing companies to manufacture their own custom dyed threads for use in the system.