A system, method, and client registration and verification device for handling personal identification information. The client device collects from an individual, a sufficient amount of biometric information to uniquely identify the individual, as well as historical mobility information providing a history of locations where the individual has lived. A caching manager stores the collected biometric information at a selected cache node in a hierarchical database having a plurality of cache nodes at multiple levels of the database. The caching manager selects the cache node based on the historical mobility information collected from the individual. The client device sends subsequent requests to verify the identity of the individual to a local cache node where newly input biometric information is compared with the cached information. When the individual's biometric information is not stored in the local cache node, the request is forwarded upward in the database until the cached information is found and compared.