The Handle System is a distributed infrastructure for assigning, managing, and resolving persistent identifiers for digital objects and other internet resources. It provides the resolution backbone for the Digital Object Identifier (DOI) system and has been deployed in numerous other applications requiring reliable, long-lived references to networked resources.
Background
The Handle System was developed in the mid-1990s by the Corporation for National Research Initiatives (CNRI) under the direction of Robert Kahn, co-inventor of TCP/IP. CNRI designed the system as part of its Digital Object Architecture, a broader framework for managing digital entities on the internet. The Handle System was first deployed around 1995 and was formally documented in three IETF informational RFCs (3650, 3651, and 3652) published in November 2003.
In 2014, administration of the Global Handle Registry (GHR) was transferred from CNRI to the DONA Foundation (Digital Object Numbering Authority), an international foundation established in Geneva to provide neutral governance of the handle infrastructure.
Purpose and Scope
The Handle System assigns identifiers called handles to digital objects. Each handle consists of a prefix (identifying the naming authority) and a suffix (identifying the specific object), separated by a forward slash. For example, 20.1000/100 identifies an object under prefix 20.1000.
Resolution converts a handle into one or more typed data values — most commonly URLs, but also email addresses, public keys, or arbitrary data types. The system supports administrative operations including handle creation, modification, deletion, and access control. Each handle can carry multiple values of different types, enabling rich metadata to be associated directly with the identifier.
Architecture
The Handle System uses a two-tier resolution architecture:
- Global Handle Registry (GHR) — maps handle prefixes to the responsible Local Handle Services
- Local Handle Services (LHS) — each operated by a naming authority, resolve individual handles within assigned prefixes
This distributed design means no single server must know about every handle. Resolution begins at the GHR, which redirects the client to the appropriate LHS. A public proxy server at hdl.handle.net provides HTTP-based resolution for web browsers.
Governance and Maintenance
The DONA Foundation manages the GHR and assigns handle prefixes. CNRI continues to develop and distribute the open-source Handle System software. The system operates under a multi-primary administrator model, where designated organizations share responsibility for the global registry.
Notable Implementations
The most prominent deployment of the Handle System is the DOI system, which uses handles for all DOI resolution. Beyond DOIs, the Handle System is used by the Defense Technical Information Center (DTIC), the European Persistent Identifier Consortium (ePIC), and numerous national libraries and research data repositories. The system resolves billions of requests annually.
Related Standards
- DOI — the largest system built on Handle infrastructure
- ARK — an alternative persistent identifier scheme that does not require central resolution