To use WLCG you must possess a personal digital certificate from a Certification Authority (CA) recognised by WLCG. The certificate will be needed both during the registration process and also when you submit jobs to the grid.

WLCG accepts certificates issued by CAs who are accredited by the IGTF: Interoperable Global Trust Federation

Certification Authorities (CA) recognised by WLCG

  • Most people should be able to get a certificate from their national CA. See this list to locate your national CA from the Interoperable Global Trust Federation.
  • CERN staff and users (e.g. members of LHC experiments) should be able to obtain a CERN user certificate - see here if you are eligible. If you are, then you can request a certificate
  • If none of the CAs above are able to issue you a certificate:
    • Please consult "Catch-all Certification Authorities for WLCG"  below for other possibilities.
    • Please contact project-lcg-certificates at cern dot ch for advice in such cases.

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Instructions for:

Catch-all Certification Authorities for WLCG

Here we describe options for obtaining certificates if ALL of the following are true:

  • you are eligible to be part of a recognized WLCG Virtual Organisation (VO) (see "Virtual Organisations" entry in list above) or work in a related project
  • you could not reasonably be expected to obtain a certificate from another approved WLCG CA (see "certificates" entry in list above)
  • you require the certificate for an activity related to WLCG or an affiliated project


If you do not have a national Certification Authority, and you are not eligible for a certificate from the CERN Grid CA, contact project-lcg-certificates at cern dot ch.

The project-lcg-certificates experts will look into your situation and advise on further action.

There are at least the following potential routes to get user and/or grid service certificates in such cases:

  • If your NREN (National Research and Education Network) is connected to GEANT, it could subscribe to the TCS service, which typically costs a few k Euro per year and then would provide the NREN with support for user and service certificates needed by the organisations it represents, e.g. universities connected to the NREN infrastructure.
  • For user certificates you may also consider the CILogon service used e.g. by OSG. Mind that, unlike OSG, WLCG only accepts certificates from the CILogon Silver CA, not the CILogon Basic CA. For more information about the requirements for obtaining a certificate from the CILogon Silver CA, please see https://ca.cilogon.org/policy/silver

Further links

Historical information

For many years, the WLCG Catch-all CA used to provide certificates for users and services not otherwise covered by one of the approved WLCG Certification Authorities (CA). The service actually was run as a "Registration Authority" (RA) of the OSG PKI. In the spring of 2018 it got decommissioned as part of a reorganisation of the OSG operations services. We thank OSG for having supported the catch-all CA service for many years!

Last updated on: 26 Jan 2022