Overview and Structure of the Handle System - Developed by Bob Kahn at the Corporation for National Research Initiatives (CNRI) - Funded by the Defense Advanced Research Projects Agency (DARPA) between 1992 and 1996 - Handles are persistent identifiers assigned to information resources - Handles are opaque and encode no information about the underlying resource - Handles are bound only to metadata regarding the resource - Handles consist of a prefix and a suffix - Prefix identifies a naming authority - Suffix gives the local name of a resource - Prefixes are issued to naming authorities by multi-primary administrators - Naming authorities can create multiple handles within their assigned prefixes

Implementation and Administration of the Handle System - Defined in informational RFCs 3650, 3651, and 3652 of the Internet Engineering Task Force (IETF) - Includes open protocols, a namespace, and a reference implementation - Handles do not encode information about the underlying resource - Metadata associated with the handle provides information about the resource - Handles are resolved using a separate step called resolution - CNRI administered and operated the Handle System until December 2015 - DONA Foundation now administers the Global Handle Registry - Multi-primary administrators (MPAs) are accredited by the DONA Foundation - Thousands of handle services are currently running - Over 200 million resolution requests are received per month

Integration and Applications of the Handle System - Provides the infrastructure for handle-based systems like Digital Object Identifiers (DOIs) and DSpace - Used to provide access to scholarly, professional, and government documents - CNRI provides specifications and source code for reference implementations - Handles can be expressed as Uniform Resource Identifiers (URIs) - Handle-based systems offer HTTP proxy servers for accessing handles - Handles are used to identify journal articles, technical reports, books, theses, and more - Handles are used in digital watermarking applications, GRID applications, and repositories - Handles can resolve to different versions of the same content or different business models - Thousands of handle services are running in 71 countries on 6 continents - Major publishers use the Handle System for persistent identification of content

Design Principles and Handle Resolution Process - Identifier string is not based on changeable attributes of the entity - Identifier string is opaque and preferably a dumb number - Identifier string is unique within the system - Identifier string has optional features like being human-readable and embeddable - Identifier resolution mechanism is reliable, scalable, flexible, trusted, and built on open architecture - Handles are passed by a client as a query to the Global Handle Registry - The Global Handle Registry responds with location information for the relevant Local Handle Service - A query is then sent to the relevant server within the Local Handle Service - The Local Handle Service returns the information needed to acquire the resource - If the client already has information on the appropriate LHS, the initial query to GHR is omitted

Global Handle Registry and Related Technologies - Global Handle Registry stores information on naming authorities within the Handle System - Global Handle Registry can be queried to find out where specific handles are stored - Global Handle Registry is a unique Local Handle Service within the distributed system - Any local handle service can resolve any handle through the Global Resolver - Global Handle Registry maintains and resolves the prefixes of locally maintained handle services - The Handle System represents components of a long-term digital object architecture - CNRI released the Digital Object Repository software, a major component of this architecture - The release includes protocol specification, source code, and ready-to-use system, clients, and utilities - The Handle System is used for persistent identification and resolution of digital objects - It provides a framework for managing digital resources and ensuring their long-term accessibility