Lexmark patents magnetic anti-counterfeit particles

Printer giant Lexmark has been awarded a US patent on a means of uncovering counterfeit ink and toner products.
The Chinese-owned corporation – based in the US – says that counterfeit printer supplies such as toner bottles are a problem for consumers as they may perform poorly and damage printers, noting that printer manufacturers are already using authentication systems to deter the fakers.
The patent draws on a concept developed by cryptographers known as physical unclonable function (PUF) – pit simply a physical entity - embodied in a physical structure – that is easy to evaluate but hard to predict or replicate. In the case of this patent the PUF is created using a mixture of magnetic and non-magnetic particles, creating a motif that can be detected using a low-cost reader.
The abstract of the patent appears below:

Physical unclonable functions having magnetic and non-magnetic particles
Abstract: A physical unclonable function (PUF) having magnetic and non-magnetic particles is disclosed. Measuring both magnetic field and image view makes the PUF difficult to counterfeit. PUF may be incorporated into a user-replaceable supply item for an imaging device. A PUF reader may be incorporated into an imaging device to read the PUF. Other systems are disclosed.
US Patent No. 9,553,582

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