Yubikey plugin for SquirrelMail
===============================
Version 1.0, 2014/03/28


Copyright (c) 2011-2014 Paul Lesniewski <paul@squirrelmail.org>
Copyright (c) 2009 Richard Ferguson <yubikey@fergusnet.com>



Description
===========

This plugin enables One-Time-Password authentication with a 
Yubikey hardware token.  This provides multi-factor 
authentication in form of something you know and something 
you have.

Two-factor authentication is accomplished by requiring both
the user's password and a Yubikey OTP.  The Yubikey OTP can be
entered in one of two ways.  Either the OTP can be combined 
with the user's password in the traditional password field, or
an additional input field can be added to the login form.
Once the login form has been submitted, the entered OTP 
is verified against Yubico's authentication service.

Yubikey authenciation must be enabled in both the system
config.php as well as on an individual basis.  User 
Yubikey options are located on the personal preferences
page.



Donations
=========

If you or your company make regular use of this software,
please consider supporting Open Source development by
donating to the authors or inquire about hiring them to
consult on other projects.  Donation/wish list links for
the author(s) are as follows:

Paul Lesniewski: https://squirrelmail.org/donate_paul_lesniewski.php



License
=======

This plugin is released under the GNU General Public
License (see the file COPYING for details).



Requirements
============

  * Squirrelmail 1.4.0 or above (The 1.5.x series is not
    supported at this time)

  * Compatibility plugin version 2.0.5 or above

  * libcurl 7.10.5

  * PHP 5 compiled with curl support (--with-curl)
    See: http://www.php.net/manual/curl.installation.php

  * A Yubikey hardware token
    See: https://store.yubico.com/

  * A client ID and secret key from Yubico
    See: https://upgrade.yubico.com/getapikey/



Troubleshooting
=============== 
  
  * If changes to the configuration file don't seem to be having
    any effect, ensure that there are not two Yubikey configuration
    files, one in the yubikey directory and one in the main
    SquirrelMail config directory (named "config_yubikey.php").
    The one in the main SquirrelMail config directory will always
    override the one in the yubikey directory. 



Help Requests 
=============

Before looking for help elsewhere, please try to help yourself:

  * Read the Troubleshooting section herein.
  
  * Look to see if others have already asked about the same issue.
    There are tips and links for the best places to do this in
    the SquirrelMail mailing list posting guidelines:
    http://squirrelmail.org/wiki/MailingListPostingGuidelines
    You should also try Google or some other search engine.

  * If you cannot find any information about your issue, please
    first mail your help request to the squirrelmail-plugins
    mailing list.  Information about it can be found here:
    http://lists.sourceforge.net/mailman/listinfo/squirrelmail-plugins
    You MUST read the mailing list posting guidelines (see above)
    and include as much information about your issue (and your
    system) as possible.  Including configtest output, any debug
    output, the plugin configuration settings you've made and
    anything else you can think of to make it easier to diagnose
    your problem will get you the most useful responses.  Inquiries
    that do not comply with the posting guidelines are liable to
    be ignored.

  * If you don't get any replies on the mailing list, you are
    welcome to send a help request to the authors' personal 
    address(es), but please be patient with the mailing list.
