The Handle System Digital Object Architecture

This system provides an architecture, upon which other systems can be built, for handling and referencing digital objects. It is a fee-based service to offset the costs of its operation.

From the web site: The Handle System® is a general purpose distributed information system that provides efficient, extensible, and secure identifier and resolution services for use on networks such as the Internet. It includes an open set of protocols, a namespace, and a reference implementation of the protocols. The protocols enable a distributed computer system to store identifiers, known as handles, of arbitrary resources and resolve those handles into the information necessary to locate, access, contact, authenticate, or otherwise make use of the resources.

A handle consists of a prefix (corresponding to the particular Handle service, also known as the naming authority) and a suffix (generated by the particular Handle service). For example, "4263537/4000" is a handle for the Handle System web site home page.