Resumen de Stability and Specificity of Counterfeit Protection System Code

Jiang-Chun Li, Fang Fang, Xing-Zhou Han, Biao Li, Wei Han, Qian Zhou

• In this study, the stability and specificity of a counterfeit protection system (CPS) code were determined. This researchinvolved an analysis of a counterfeit protection system code unit over time using the pattern location measurement method. We collected 379sample sheets from 196 printers or photocopiers, covering 14 original brands, including 129 models. There was an interval of at least twomonths between the collections of samples from each machine. Four types of characteristics were established: CPS pattern unit, distance of theCPS unit, position of dots, size and shape of the dot. Except for the partial changes in the Xerox brand, no other brand exhibited changes overtime. This implies that the CPS characteristics are stable. Meanwhile, no correlation was noted between the combinations of the characteristicsystems in the collected samples, which implied strong specificity.