Digital Object Identifier System
DOIs are composed of a prefix and a suffix which are separated by a slash (e.g. “10.1234/cdb2011-01-bio234”). Organizations that want to participate in the DOI system have to apply for an account at a registration agency which will assign a unique DOI prefix to the organization (e.g. “10.1234”). The organization can then assign arbitrary suffixes to their digital objects as long as they guarantee that no suffix will be repeated (e.g. “cdb2011-01-bio234” in the above example). Sometimes several organizations share a DOI prefix to reduce the cost of DOI registration.
Once a prefix has been obtained and a suffix assigned to a publication object, the DOI composed of prefix and suffix has to be registered with the registration agency. The publishing organization formats metadata corresponding to the publication object into the metadata format specific to the registration agency. The resulting XML file will then be transmitted to the registration agency together with the DOI and the corresponding URL of the publication object.