YubiKey authentication token

Created by BJ Smith, last modified on 2022-08-03

YubiKey authentication tokens enable authorized users to access a variety of UCAR resources. These include high-performance computing systems managed by CISL (see below) and the virtual private network (VPN).

YubiKey4 token

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Getting started

To be able to use your YubiKey token, you first need to complete the appropriate form and send it to the fax number on the form.

Complete the Duo/YubiKey4 Acknowledgement Form (click to download). If you have arranged to have a YubiKey 4 token, you will use it in combination with your CIT password.

By signing the acknowledgement form, you agree to fulfill your responsibilities as a user and to protect your token as follows:

  • Your token will remain in your custody and is for your use only; it may not be shared.
  • You will immediately (within 48 hours) report loss of custody of your hardware authentication token to the CISL Help Desk at x2400 (303-497-2400). Loss of custody may be due to loss or theft.
  • Your CIT password may not be shared or made available in unencrypted electronic form.
  • You will report any disclosure of your CIT password to the CISL Help Desk at x2400 (303-497-2400) and/or to the UCAR Security Operations Center at x4300 (307-996-4300). 

In addition, you acknowledge that acceptance of this token constitutes an understanding that the token is export controlled such that export/re-export to Cuba, Iran, Syria, North Korea, or Sudan is strictly prohibited.

Special requirement for Mac OS X systems only

A user with admin privileges who can tell the system to permanently recognize the token must plug the token in initially. This will let you avoid having to go through three dialog boxes every time you log in.

When the dialog box asks you to press the key to the right of the SHIFT key, touch the button on the token instead.

Logging in with a YubiKey 4

To log in to a CISL system – Cheyenne, in this example – use the ssh command and your UCAR username as shown.

ssh -X

The system will prompt you to enter a token response.

Using keyboard-interactive authentication.

To respond:

  • Insert your token in a USB port. If you have a MacBook or other computer or mobile device with a USB-C port, you will need a USB-C adapter.
  • Type your CIT password into the “Token_Response” field.
  • Lightly touch the gold button on your token. (The button is not activated by pressure. Rather, it reacts to contact with your finger.) This will insert a new one-time password and you will be logged in.

You can open more than one login session, but you must complete the authentication process for each session before opening another one.

Protecting your token

Here are some tips for taking proper care of this electronic device.

  • Keep it away from magnets, microwaves, electrostatic shock, and X-rays. (Security checkpoints, such as those at airports, are OK.)
  • Do not expose it to temperatures below -5 degrees Fahrenheit, above 120 degrees, or above 90 degrees for sustained periods. (Avoid leaving it on your car’s dashboard on a hot day, for example.)

Replacing or returning a token

Contact the CISL Help Desk if you need to replace or exchange your YubiKey 4 token.

Users who lose or damage a YubiKey 4 token or fail to return it when required will be billed $60. The fee can be paid by credit card on the UCAR Payment Web Site or billed to the user's NCAR/UCAR account key.

For security reasons, the CISL Help Desk cannot routinely arrange temporary access for users who forget to bring an authentication token to work. If you are out of town and need emergency access, the NCAR Research Computing help desk.

Loss, theft, or compromise

Loss, theft, or compromise of a YubiKey 4 must be reported within 48 hours to the CISL Help Desk at x2400 (303-497-2400). Quick reporting will help the organization minimize security risk.


If you return a token intact within three months after having paid for it, we will issue a credit to your credit card or to the NCAR division that paid for the token if you provide a receipt or other documentation that the charge was approved.


See Returning your YubiKey 4 token.