Counterfeiting of products, particularly replacement parts for machinery, is more rampant than ever. Verifying the authenticity of a replacement part, or other product, throughout the chain of distribution is therefore more important than ever. Simple printed labels can be easily counterfeited. Therefore, there is a need for sophisticated labels which will foil attempts at counterfeiting. Also, security labels should thwart attempts to tamper with the labels, or to switch them from one part to another.