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 (WEhowski IDentifier) 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 defining sub-namespaces.

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

• Namespace weid: (Also called “Class C” WEID)
  • Root OID is 1.3.6.1.4.1.37553.8
  • Example: OID 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 be 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:

• Free OID by Viathinksoft
• “Public” OID by Frdlweb

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

• In 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 lowercase can be interpreted, too.
• The URN namespace (weid:, weid:pen:, weid:root:) is case insensitive, but it is recommended to write it in lowercase.
• Padding with 0 characters is valid (e.g. weid:000EXAMPLE-3), but not recommended. The paddings do not count toward 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 the 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.

Changes with Spec Change 10: Domain-WEID:

• Spec Change 10 (07 August 2023) allows domain names to be used as WEID sub-namespace.
• All WEID sub-namespaces containing at least one dot (.) are treated as domain names.
• The notation weid:example.com:ABC-DEF-? is equal to weid:9-DNS-COM-EXAMPLE-ABC-DEF-?.
• The resulting WEID is called Domain-WEID or “Class D” WEID.
• Note that the check digit is equal for both notations since it is based on the resulting OID.
• TLD-Only domains are not allowed for the purpose of forming a Domain-WEID.
• A Domain-WEID can be converted to Class A/B/C WEID, but the reverse conversion is ambiguous (“where does the domain name end and the identifier part start?”)

Changes with Spec Change 11: Proprietary Namespaces:

• Spec Change 11 (07 August 2023) allows custom / vendor-specific WEID sub-namespaces.
• Such namespaces must begin with x-, for example: weid:x-contoso:ABC-DEF-? could be a WEID defined by Contoso Ltd.
• As usual for WEID, the namespace is case insensitive.
• To avoid confusion with Spec Change 10 Domain-WEID, the sub-namespace must not contain a dot (.).
• The vendor has complete control over the namespace and can define the behavior. However, it is recommended to make use of Base36 and the weLuhn check digit.
• Since the vendor specifies the namespace, it is up to the vendor if they allow the mapping of their WEID-Namespace to the OID-Tree. In comparison to class A/B/C/D WEID which are 100% OID compatible, custom WEID might not be OID-compatible at all.

• Currently, the following custom namespaces are known:

  • weid:x-frdl:[Base36_NS]-[SubNS]:[Base36_ID]-[CheckDigit] to be defined/implemented by Frdlweb (base idea here).
  • If you know more namespaces, or if you are the author of a custom namespace, please let us know.

Additional notes:

• Any WEID (except for Custom WEID as defined in Spec Change 11) 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 strongly encourage allowing arbitrary length arcs (i.e. implementing BigInteger rather than 32-bit integers)
• At www.weid.info you can find more information and announcements of changes.

The current version of the specification is 11, which is identified with the OID 1.3.6.1.4.1.37553.8.1.8.1.6.1.11 (weid:1-8-1-6-1-B-7).

© WEID is developed by Daniel Marschall / ViaThinkSoft and Till Wehowski.