Grid Certificate

Last update: 03 Nov 2024 [History] [Edit]

It is important that your grid certificate is working for your analysis. You may also be unable to fully participate in some sections of hands-on exercises (or ATLAS analysis work) which require a valid grid proxy.

Important note about Security

The grid certificate you obtain below is your identity to ATLAS resources. Whether it as a p12 file, or later generated as a userkey.pem file, it must be kept private and secure. The passphrase must not be shared with anyone.

Important note about Windows

CERN provides certificate support for Linux and MacOS and the ATLAS experts are not familiar with the necessary steps for Windows. Therefore, if you are working on a Windows machine, please do one of the following:

  • Borrow a Linux or MacOS machine to request, download, and extract your certificate.
  • Dual boot your machine to run Linux or run a Linux Virtual Machine. It is possible that Windows Subsystem for Linux (WSL) will enable you to do this, but it is not certain.

Request a certificate

If you do not have a grid certificate, you may be able to request one from https://ca.cern.ch/ca/. Make sure you are using Firefox when going to the site. Select the “New Grid User certificate” option and follow the instructions, including providing a passphrase to protect the certificate.

After obtaining your certificate and installing it in your browser, continue through the next section to apply for the ATLAS VO membership. The remainder of the grid certificate instructions are given afterwards.

tip MacOS users: Download the p12 file from the link when you create it. You will need to do it this way instead of exporting it from your keychain. (The issue is that MacOS keychain exports a legacy version of p12.) You can also add it to your keychain after downloading.