WEID Specification

An Object Identifier (OID) is an extensively used identification mechanism jointly developed by ITU-T and ISO/IEC for naming any type of object, concept, or "thing" with a globally unambiguous name. (More information about OIDs can be found at www.oid-info.com )

There are three well-known notations for OIDs:

Dot-notation: 2.999
ASN.1 notation: {joint-iso-itu-t(2) example(999)}
OID-IRI notation: /Joint-ISO-ITU-T/Example

WEID is another notation for OIDs, developed by Till Wehowski and Daniel Marschall:

WEID notation: weid:root:2-RR-2

In the initial version of the WEID specification of 2011, only OIDs below the WEID root arc 1.3.6.1.4.1.37553.8 could be used. In a later definition by Daniel Marschall, any existing OID can be written in WEID notation, by switching defining sub-namespaces.

The registry of sub-namespaces (URN prefixes) has currently following entries:

Namespace “weid:” (Also called “Class C” WEID)
- Root OID is 1.3.6.1.4.1.37553.8
- Example: 1.3.6.1.4.1.37553.8.32488192274
- … can be written as weid:EXAMPLE-3 (3 is the check-digit)
- The registration of WEID Alphanumeric OIDs beneath this arc is managed by Webfan.de in order of FRDLWEB. You can assign as Private WEID by Frdlweb here: https://registry.frdl.de/?goto=com.frdlweb.freeweid
Sub-Namespace “weid:pen:” (Also called “Class B” WEID)
- Root OID is 1.3.6.1.4.1
- Example OID: 1.3.6.1.4.1.37476.9999
- … can be written as weid:pen:SX0-7PR-6 (6 is the check-digit)
- The registration of Private Enterprise Numbers (PEN) is managed by IANA. You can register a PEN here: https://pen.iana.org/pen/PenApplication.page
Sub-Namespace “weid:root:” (Also called “Class A” WEID)
- Root OID is the OID tree root
- Example OID: 2.999
- … can bet written as weid:root:2-RR-2 (2 is the check-digit)
More sub-namespaces can be added to this registry in the future. The sub-namespaces must be defined by the WEID consortium (ViaThinkSoft and WebFan) in a Specification Change.

To get an OID in accordance with Recommendation ITU-T X.600 assigned, you need to find a Registration Authority that assigns you an OID. You can obtain an OID as WEID and manage your own arc, e.g. by:

The construction of a WEID is demonstrated with the example OID 2.999:

The numeric arcs (e.g. “2” and “999”) are converted from base 10 to base 36, so the arcs become “2” and “RR”.
The arcs are separated by a hyphen “-“, so we have now “2-RR”.
Now, an appropriate namespace (and sub-namespace if applicable) will be added. In our case, a fitting (sub-)namespace is “weid:root:”, so we now have “weid:root:2-RR”
At the end, a Luhn-based check-digit (called WeLuhn) is added. If the WEID contains at least one arc, then the check-digit is preceded by a hyphen.
- The WeLuhn algorithm works this way:
- First, we take the OID in dot-notation (e.g. “2.999”)
- The arcs will be converted from base 10 to base 36, so we have “2-RR”. Padding zeros must not be present and need to be stripped.
- The hyphens are removed, so we now have “2RR”.
- “A” will be replaced with “10”, “B” will be replaced with “11”, etc., so we now have “22727”
- This number is the payload for the normal Luhn algorithm. https://en.wikipedia.org/wiki/Luhn_algorithm which works as follows:
  - Start from the rightmost digit. Moving left, double the value of every second digit (including the rightmost digit).
  - Sum the digits of the resulting value in each position.
  - Sum the resulting values from all positions, s .
  - The check digit is calculated by ((10-s mod 10) mod 10) .
    - In our case, the Luhn checksum is “2”
Our final WEID notation for OID 2.999 is “weid:root:2-RR-2”.

Recommendations for WEID notation (as of Spec Change 8):

When choosing a (sub-)namespace, it is recommended to choose a sub-namespace that is closest to the OID you want to describe, producing the shortest WEID therefore. For example, weid:pen:SX0-7PR-6 should be chosen rather than weid:root:1-3-6-1-4-1-SX0-7PR-6
The arcs in a WEID should be written in upper-case, but lower-case can be interpreted, too.
The URN namespace (weid:, weid:pen:, weid:root:) is case insensitive, but it is recommended to write it in lower-case.
Padding with “0” characters is valid (e.g. weid:000EXAMPLE-3), but not recommended. The paddings do not count into the WeLuhn check-digit.

Recommendations for WEID notation (as of Spec Change 9):

In Spec Change 9 (08 March 2022), an alternative syntax of WEIDs is defined. This alternative syntax replaces the checksum with a wildcard in form of a question mark symbol, for example, weid:root:2-RR-? instead of weid:root:2-RR-2. One useful scenario can be the documentation of incomplete/template WEIDs. Another usage is converters (like our online converter) which can help you replace the wildcard with the correct checksum.

Additional notes:

Any WEID can be represented by an OID and vice-versa. Therefore, a WEID has all attributes of an OID (e.g. it can be used to generate a Version 5 SHA1 name-based UUID with the Namespace UUID “6ba7b812-9dad-11d1-80b4-00c04fd430c8” according to IETF RFC-4122).
Please note that some clients handling OIDs cannot handle arcs that have a specific size (more information here). Implementers of WEID and strongly encourage to allow arbitrary length arcs (i.e. implementing BigInteger rather than 32-bit integers)
In the OIDplus Registration Authority at arc 1.3.6.1.4.1.37553.8.1.8.1.6 you can find more information and announcements of changes.

WEID OID notation

WEID Specification