Artifact-metrics is an automated method of utilizing artifacts based on their measurable intrinsic characteristics such as microscopic random-patterns and the like which are inherently emerging in their manufacturing process. This method is a kind of sibling technology with Biometrics. This article describes an introductory overview of artifact-metrics with a list of examples including classical paper-based ones as well as a brand-new instance based on nano-photonics. An intrinsic characteristic is called an artifact-metric element. If an artifact-metric element has enough (1) individuality, (2) stability in capturing, (3) durability, and (4) clone-resistance then it can be applied to artifact-metric systems designed for (a) authentication and for (b) reproducing exact values. The former application is well studied and there are many actually used optical systems for plain or micro-magnetic-fiber-embedded paper. The latter application belongs to a relatively new field called physically unclonable functions, which is studied extensively in the context of semiconductor electronic circuits for cryptography.
