digest\_file\_auth(8) System Manager's Manual digest\_file\_auth(8)

# [NAME](#NAME)

digest\_file\_auth - File based digest authentication helper for Squid.

Version 1.1

# [SYNOPSIS](#SYNOPSIS)

**digest\_file\_auth** **\[-c]** file

# [DESCRIPTION](#DESCRIPTION)

**digest\_file\_auth** is an installed binary authentication program for Squid. It handles digest authentication protocol and authenticates against a text file backend. This program will automatically detect the existence of a concurrency channel-ID and adjust appropriately. It may be used with any value 0 or above for the auth\_param children concurrency= parameter.

# [OPTIONS](#OPTIONS)

[**-c**](#c)

Accept digest hashed passwords rather than plaintext in the password file

# [CONFIGURATION](#CONFIGURATION)

Username database file format:

[- comment lines are possible and should start with a '#';](#comment)

[- empty or blank lines are possible;](#empty)

[- plaintext entry format is username:password](#plaintext)

[- HA1 entry format is username:realm:HA1](#HA1)

To build a directory integrated backend, you need to be able to calculate the HA1 returned to squid. To avoid storing a plaintext password you can calculate **MD5(username:realm:password)** when the user changes their password, and store the tuple **username:realm:HA1.** then find the matching **username:realm** when squid asks for the HA1.

This implementation could be improved by using such a triple for the file format. However storing such a triple does little to improve security: If compromised the **username:realm:HA1** combination is "plaintext equivalent" - for the purposes of digest authentication they allow the user access. Password synchronization is not tackled by digest - just preventing on the wire compromise.

# [AUTHOR](#AUTHOR)

This program was written by *Robert Collins <robertc@squid-cache.org>*

Based on prior work by *Arjan de Vet <Arjan.deVet@adv.iae.nl>*

This manual was written by *Robert Collins <robertc@squid-cache.org>* *Amos Jeffries <amosjeffries@squid-cache.org>*

# [COPYRIGHT](#COPYRIGHT)

\* Copyright (C) 1996-2026 The Squid Software Foundation and contributors  
\*  
\* Squid software is distributed under GPLv2+ license and includes  
\* contributions from numerous individuals and organizations.  
\* Please see the COPYING and CONTRIBUTORS files for details.

This program and documentation is copyright to the authors named above.

Distributed under the GNU General Public License (GNU GPL) version 2 or later (GPLv2+).

# [QUESTIONS](#QUESTIONS)

Questions on the usage of this program can be sent to the *Squid Users mailing list* <squid-users@lists.squid-cache.org>

# [REPORTING BUGS](#REPORTING_BUGS)

Bug reports need to be made in English. See https://wiki.squid-cache.org/SquidFaq/BugReporting for details of what you need to include with your bug report.

Report bugs or bug fixes using https://bugs.squid-cache.org/

Report serious security bugs to *Squid Bugs <squid-bugs@lists.squid-cache.org>*

Report ideas for new improvements to the *Squid Developers mailing list* <squid-dev@lists.squid-cache.org>

# [SEE ALSO](#SEE_ALSO)

[**squid**(8)](/man/enterprise-packages/squid/squid.8), [**GPL**(7)](/man/enterprise-packages/squid/GPL.7),  
The Squid FAQ wiki https://wiki.squid-cache.org/SquidFaq  
The Squid Configuration Manual http://www.squid-cache.org/Doc/config/

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Document: digest_file_auth(8) from squid 7.7-r3 (Chainguard OS)
Source: https://github.com/squid-cache/squid.git