documentation:2.0:yubikey2f
Keywords: documentation,2.0,yubikey2f

# Yubikey Second Factor

A Yubikey is a small material token manufactured by Yubico. It sends an OTP, which is validated via Yubico server.

## Prerequisites and dependencies

You must install Auth::Yubikey_WebClient package.

You have to retrieve a client ID and a secret key from Yubico. See Yubico API page.

## Configuration

In the manager (second factors), you just have to enable it:

- Activation: set it to “on”
- Self registration: set it to “on” if users are authorized to register their keys
- Authentication level: you can overwrite here auth level for Yubikey registered users. Leave it blank keeps auth level provided by first authentication module (default: 2 for user/password based modules). It is recommended to set an higher value here if you want to give access to some apps only to enrolled users
- Client ID: given by Yubico or another service
- API secret key: given by Yubico or another service
- Nonce (optional): if any
- URL: Url of service (leave blank to use Yubico cloud services)
- OTP public ID part size: leave it to default (12) unless you know what you are doing

If you want to use a custom rule for “activation” and want to keep self-registration, you must include this in your rule: `$_2fDevices =~ /“type”:\s*“UBK”/s`, else Yubikey will be required even if users are not registered. This is automatically done when “activation” is simply set to “on”.

## Provisioning

If you don't want to use self-registration, set public part of user's yubikey in Second Factor Devices array (JSON) in your user-database. Then map it to the _2fDevices attribute (see exported variables):

    [{"name" : "MyYubikey" , "type" : "UBK" , "_secret" : "########" , "epoch":"1524078936"}, ...]

## Enrollment

If you have enabled self registration, users can register their U2F keys using https://portal/2fregisters