Using the uniqueness of certain human features to identify an individual has been possible for many years. At the end of the nineteenth century, fingerprints began to be used in crime detection, which provided a high degree of success in identification with a low risk of false positive results. This tool has been added to with such techniques as iris recognition, facial mapping and DNA matching. Some of these biometric tests are beginning to be used in the fight against identity fraud.

The usefulness of any technique depends upon its simplicity of implementation, and its convenience to the user, coupled with a high probability of uniqueness (i.e. a low risk of matching the wrong person). Methods such as DNA matching are too complex to provide a useful mechanism for most computer applications, but fingerprint and iris recognition provide more viable mass-market solutions; already some laptops, peripherals and storage devices incorporate fingerprint recognition technology.