The International Organization for Standardization has published ISO 26324:2012, Information and Documentation—Digital Object Identifier System.
Here's an excerpt from the press release:
A DOI name is an identifier of an entity—physical, digital or abstract—on digital networks. It provides information about that object, including where the object, or information about it, can be found on the Internet. . . .
ISO 26324:2012 gives the syntax, description and resolution functional components of the digital object identifier system. It also gives the general principles for the creation, registration and administration of DOI names.
The DOI system was initiated by the International DOI Foundation (a not-for profit member-based organization initiated by several publishing organizations) in 1998.