object identifier

Senses

1 (N)

An official, globally unique name for a thing, written as a sequence of integers (which are formed and assigned as defined in the ASN.1 standard) and used to reference the thing in abstract specifications and during negotiation of security services in a protocol.

IETF RFC 4949 (Internet Security Glossary)

Bibliography

IETF RFC 4949 (Internet Security Glossary)
Accessed Jan 06, 2026Quoted
RFC 4949 — Internet Security Glossary (Version 2)
https://www.rfc-editor.org/rfc/rfc4949.txt
RFC 4949 is published by the IETF Trust and marked as "Distribution of this memo is unlimited". Verify IETF Trust copyright/licensing terms for reuse.
Source: IETF RFC 4949 (rfc-editor.org).

2 (O)

"A value (distinguishable from all other such values) [that] is associated with an object." [X680] Tutorial: Objects named by OIDs are leaves of the object identifier tree (which is similar to but different from the X.500 Directory Information Tree). Each arc (i.e., each branch of the tree) is labeled with a non negative integer. An OID is the sequence of integers on the path leading from the root of the tree to a named object. The OID tree has three arcs immediately below the root: {0} for use by ITU T, {1} for use by ISO, and {2} for use by both jointly. Below ITU T are four arcs, where {0 0} is for ITU T recommendations. Below {0 0} are 26 arcs, one for each series of recommendations starting with the letters A to Z, and below these are arcs for each recommendation. Thus, the OID for ITU T Recommendation X.509 is {0 0 24 509}. Below ISO are four arcs, where {1 0 }is for ISO standards, and below these are arcs for each ISO standard. Thus, the OID for ISO/IEC 9594 8 (the ISO number for X.509) is {1 0 9594 8}. ANSI registers organization names below the branch {joint iso ccitt(2) country(16) US(840) organization(1) gov(101) csor(3)}. The NIST CSOR records PKI objects below the branch {joint iso itu t(2) country(16) us(840) organization (1) gov(101) csor(3)}. The U.S. DoD registers INFOSEC objects below the branch {joint iso itu t(2) country(16) us(840) organization(1) gov(101) dod(2) infosec(1)}. The IETF's Public Key Infrastructure (pkix) Working Group registers PKI objects below the branch {iso(1) identified organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7)}. [R3280]

"A value (distinguishable from all other such values) [that] is associated with an object." [X680]

Tutorial: Objects named by OIDs are leaves of the object identifier tree (which is similar to but different from the X.500 Directory Information Tree). Each arc (i.e., each branch of the tree) is labeled with a non-negative integer. An OID is the sequence of integers on the path leading from the root of the tree to a named object.

The OID tree has three arcs immediately below the root: {0} for use by ITU-T, {1} for use by ISO, and {2} for use by both jointly. Below ITU-T are four arcs, where {0 0} is for ITU-T recommendations. Below {0 0} are 26 arcs, one for each series of recommendations starting with the letters A to Z, and below these are arcs for each recommendation. Thus, the OID for ITU-T Recommendation X.509 is {0 0 24 509}. Below ISO are four arcs, where {1 0 }is for ISO standards, and below these are arcs for each ISO standard. Thus, the OID for ISO/IEC 9594-8 (the ISO number for X.509) is {1 0 9594 8}.