There are mainly the following types of anti-counterfeiting inks: thermochromic anti-counterfeiting inks, whose principle is that the colorant uses a substance whose color changes with temperature; photochromic anti-counterfeiting inks, whose principle is to add photochromic or light-activated compounds to the ink; humidity-sensitive color-changing anti-counterfeiting inks, whose principle is to add a substance whose color changes with humidity to the colorant; pressure-sensitive color-changing anti-counterfeiting inks, whose principle is to add pressure-induced color-changing compounds or microcapsules to the ink; ultraviolet fluorescent anti-counterfeiting inks, whose principle is to add visible fluorescent compounds excited by ultraviolet light to the ink.