Lighttpd secure digest authentication (mod_auth)

by on October 22, 2006 · 16 comments· LAST UPDATED July 5, 2007


Lighttpd logo

This method transfers the username and the password in cleartext over the network (base64 encoded) and might result in security problems if not used in conjunction with a crypted channel between client and server.

The Digest method only transfers a hashed value over the network which performs a lot of work to harden the authentication process in insecure networks.

There are total three steps to configure Lighttpd secure digest authentication:
=> Setup username and password using htdigest (Apache program)
=> Configure lighttpd core directives
=> Apply restrictions to selected directories aka set password protected directory

Step # 1: Setup username and password using htdigest (Apache program)

Command htdigest is used to create and update the flat-files used to store usernames, realm and password for digest authentication of HTTP users. Genreal syntax is as follows:
htdigest -c /path/to/password/file 'Realm' username

For example add a user called tom:
# htdigest -c /etc/lighttpd/.passwd 'Authorized users only' tom


  • -c: Create the /etc/lighttpd/.passwd
  • /etc/lighttpd/.passwd: Password file name. It contain the username, realm and password. If -c is given, this file is created if it does not already exist, or deleted and recreated if it does exist.
  • 'Authorized users only': The realm name to which the user name belongs
  • tom: The user name (tom) to create or update in /etc/lighttpd/.passwd. If username does not exist is this file, an entry is added. If it does exist, the password is changed.

Step # 2: Configure lighttpd core directives

Open /etc/lighttpd.conf file.# vi /etc/lighttpd.confMake sure mod_auth is loaded:
server.modules += ( "mod_auth" )Now, append following 3 lines:
auth.backend = "htdigest"
auth.backend.htdigest.userfile = "/etc/lighttpd/.passwd"
auth.debug = 2

Step # 3: Apply restrictions to selected directories aka set password protected directory
Let us say you would like to protect directory called /docs ( Append following directives (/etc/lighttpd.conf file):
auth.require = ( "/docs/" =>
"method" => "digest",
"realm" => "Authorized users only",
"require" => "valid-user"

Save and close the file.

Restart the lighttpd:
# /etc/init.d/lighttpd restart

You can always find more debugging information in your error log file -/var/log/lighttpd/error.log:
# tail -f /var/log/lighttpd/error.log

Point a web browser to or http://localhost/docs/ or http://ip-address/docs. You should be prompted for a username (for e.g. tom) and password (your password).

For additional security it is recommended that you use SSL configuration.

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{ 16 comments… read them below or add one }

1 Thai Mai July 5, 2007 at 1:49 pm

Great article. Works after one small type correction.

you wrote:

auth.backend.htdigest.userfile = "/etc/lighttpd/.passwd "

I copied and pasted the above and couldn’t restart lighttpd. There’s a space after .passed and before the ending quote. Removing the space, lighty started fine.

Thanks for this tutorial and all the others.


2 nixCraft July 5, 2007 at 3:16 pm


Opps, sorry for typo, post has been updated.

Appreciate your post!


3 kunal July 27, 2007 at 9:05 am

if i have some fils in the http folder and in browser i write

it gives me an error 404 not found and in have done secure digest authentication on the http folder

why i m getting this problem i m not able to figure it out.

please help me. Thanks in advance


4 anon January 31, 2008 at 8:13 am

Unfortunately lighttpd still doesnt write meaningful entries into error.log on failed logins so its hard to check for wordbook attacks etc.


5 mumuri May 18, 2008 at 2:26 pm

htdigest is available on apache2-utils, if you don’t have it, you can install it by this cmd on debian system

apt-get install apache2-utils


6 peter July 22, 2008 at 10:52 am

what should be the correct unix permissions for .passwd?

I’m getting this error:
2008-07-22 11:44:23: (http_auth.c.151) opening digest-userfile /etc/lighttpd/.passwd failed: Permission denied


7 nixCraft July 22, 2008 at 12:33 pm


You should set permission to lighttpd or www i.e. lighttpd server username using chmod command.


8 Peter July 22, 2008 at 6:32 pm

# ls -la /etc/lighttpd/
drw-r—– 2 www www 512 Jul 22 19:16 .
drwxr-xr-x 21 root wheel 2048 Jul 21 14:30 ..
-rw-r–r– 1 www www 60 Jul 22 19:16 .passwd

# tail -f /var/log/lighttpd.error.log
2008-07-22 19:27:50: (http_auth.c.1002) username xpto
2008-07-22 19:27:50: (http_auth.c.1003) realm Authorized users only
2008-07-22 19:27:50: (http_auth.c.1004) nonce 27292a400655857236e04710538278ba
2008-07-22 19:27:50: (http_auth.c.1005) uri /wordpress/wp-admin/
2008-07-22 19:27:50: (http_auth.c.1006) algorigthm MD5
2008-07-22 19:27:50: (http_auth.c.1007) qop auth
2008-07-22 19:27:50: (http_auth.c.1008) cnonce 21nkwLwMcFj1CHbiIF9IzfvpLzHgiNpzNzZEJzptCcW=
2008-07-22 19:27:50: (http_auth.c.1009) nc 00000001
2008-07-22 19:27:50: (http_auth.c.1010) response 96649fb136d6c4fc4bfd21e13a7d7f23
2008-07-22 19:27:50: (http_auth.c.151) opening digest-userfile /etc/lighttpd/.passwd failed: Permission denied


9 nixCraft July 22, 2008 at 8:07 pm

What is output of the following command?
grep -i server.username /etc/lighttpd/lighttpd.conf
You need to use that username, also make sure, /etc/lighttpd also owned by that user.


10 Peter July 22, 2008 at 8:38 pm

# grep -i server.username /usr/local/etc/lighttpd.conf
server.username = “www”

I created the .passwd on another machine running apache, but I think that’s not the cause of this error


11 max October 5, 2008 at 1:15 pm

When we do this is there any way to prevent browser pop-up ..i want to process response in my javascript but 401 gives control to browser.

Is any alternative to get nonce &pass it to javascript (like creating socket & GET request on server side with cgi & then changing 401 code to something random). I want gui of my javascript.

Please reply


12 Starbeamrainbowlabs November 2, 2014 at 2:54 pm

You would need to write a login script manually with PHP in order to do that as far as I know, it is the browser makers who control what the login box looks like with this method.


13 George February 28, 2009 at 1:54 pm

apt-get install apache2-utils

to get htdigest.


14 Lindon July 8, 2011 at 7:26 pm


is php needed for this to work?


15 Sandeep April 22, 2013 at 6:26 am

Hi I am able to setup the wholw thing and the site is asking for authentication. Now the problem is I want to change the appearance of the authentication dialog box. So can anyone help me find where exactly the call point for this dialog box is present, so that i can map my dialog box to it.


16 Starbeamrainbowlabs November 2, 2014 at 2:55 pm

An alternative to the htdigest command found in apache2-utils can be found on this page:


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