Object identifier

An object identifier or OID is an identifier used to name an object (compare URN). Structurally an OID is a node in a hierarchically assigned namespace, formally defined using the ITU-T's ASN.1 standard. Each node in the tree is identified by the numbers of the nodes starting at the root of the tree. New nodes are created by registering them under the node's registration authority. The root of the tree contains the following three "arcs":

• 0: ITU-T
• 1: ISO
• 2: joint-iso-itu-t

The most common OIDs seen "in the wild" are the private enterprise numbers allocated by IANA under the 1.3.6.1.4.1 (iso.org.dod.internet.private.enterprise) arc.

Usage

• In computer security, OIDs are used for naming almost every object type in X.509 certificates, such as components of Distinguished names , CPSs , etc.
• In computer networking, an OID, in the context of the Simple Network Management Protocol (SNMP), consists of the object identifier for an object in a Management Information Base (MIB).

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In computer programming, an object identifier is generally an implementation-specific integer or pointer that uniquely identifies an object.

External links

• Object Identifier Tree
• Harald Tveit Alvestrand's Object Identifier Registry
• IANA Private Enterprise Numbers