Second Factors

Two-Factor Authentication (as known as 2FA) is a kind (subset) of multi-factor authentication. It is a method to confirm a user’s claimed identity by using a combination of two different factors between:

  1. something they know (login / password, …)
  2. something they have (U2F Key, smartphone, …)
  3. something they are (biometrics like fingerprints, …)

Since 2.0, LLNG provides some second factor plugins that can be used to complete authentication module with 2FA :

The E-Mail, External and REST 2F modules may be declared multiple times with different sets of parameters.

Registration on first use

If you want to force a 2F registration on first login, you can use the Force 2FA registration at login option.

You can use a rule<writingrulesand_headers> to enable this behavior only for some users.

Second factor expiration

You can display a message if an expired second factor has been removed by enabling Display a message if an expired SF is removed option or setting a rule.

Self-care on Portal

User may register second factors themselves on the Portal by using the 2FA Manager.

The link will be displayed if at least one SFA module is enabled. You can set a rule to display or not the link.

Session upgrade through 2FA


If you enable the Use 2FA for session upgrade option, second factor will only be asked on login if the target application requires an authentication level that is strictly higher than the one obtained by the Authentication backend (first factor).

The session upgrade mechanism will only require the second factor step, instead of doing a complete reauthentication.

Providing tokens from an external source

If you don’t want to use self-registration features for U2F, TOTP and so on, you can set tokens by yourself (in your LDAP server for example) and map it to _2fDevices attribute. _2fDevices is a JSON array that contains token descriptions :

[ {"type" : "TOTP", "name" : "MyTOTP", …}, {<other_token>}, …]

U2F Tokens

{"name" : "MyU2FKey" , "type" : "U2F" , "_userKey" : "########" , "_keyHandle":"########" , "epoch":"1524078936"}

TOTP Tokens

{"name" : "MyTOTP" , "type" : "TOTP" , "_secret" : "########" , "epoch" : "1523817955"}

Yubikey Tokens

{"name" : "MyYubikey" , "type" : "UBK" , "_yubikey" : "########" , "epoch" : "1523817715"}

Developer corner

To develop a new 2FA plugin, read Lemonldap::NG::Portal::Main::SecondFactor (3pm) manpage. Your 2F module must be a Perl class named Lemonldap::NG::Portal::2F:://<custom_name>//. To enable it, set available2F key in your lemonldap-ng.ini file :

available2F = U2F,TOTP,<custom_name>

To enable manager Second Factor Administration Module, set enabledModules key in your lemonldap-ng.ini file :

enabledModules = conf, sessions, notifications, 2ndFA