Argon2 OpenLDAP support
----------------------

argon2.c provides support for ARGON2 hashed passwords in OpenLDAP. For
instance, one could have the LDAP attribute:

userPassword: {ARGON2}$argon2i$v=19$m=4096,t=3,p=1$c2FsdHNhbHQ$DKlexoEJUoZTmkAAC3SaMWk30El9/RvVhlqGo6afIng

or:

userPassword: {ARGON2}$argon2i$v=19$m=4096,t=3,p=1$c2FsdHNhbHRzYWx0$qOCkx9nMeFlaGOO4DUmPDgrlUbgMMuO9T1+vQCFuyzw

Both hash the password "secret", the first using the salt "saltsalt", the second using the salt "saltsaltsalt"

Building
--------

This module is now part of regular OpenLDAP build process and enabled if
libsodium or libargon2 library and the corresponding development headers are
present. You can also choose the library to build against if you prefer by
passing --enable-argon2=<libsodium|libargon2> to your configure invocation.

Configuring
-----------

Load the argon2 module (e.g. with olcModuleLoad or moduleload) and the
{ARGON2} password scheme should now be recognised.

You can also tell OpenLDAP to use one of this scheme when processing LDAP
Password Modify Extended Operations, thanks to the password-hash option in
slapd.conf:

password-hash	{ARGON2}


Testing
-------

A quick way to test whether it's working is to customize the rootdn and
rootpw in slapd.conf, eg:

rootdn          "cn=admin,dc=example,dc=com"

# This hashes the string 'secret', with a random salt
rootpw          {ARGON2}$argon2i$v=19$m=4096,t=3,p=1$uJyf0UfB25SQTfX7oCyK2w$U45DJqEFwD0yFaLvTVyACHLvGMwzNGf19dvzPR8XvGc


Then to test, run something like:

ldapsearch -b "dc=example,dc=com" -D "cn=admin,dc=example,dc=com" -x -w secret


-- Test hashes:

Test hashes can be generated with argon2:
$ echo -n "secret" | argon2 "saltsalt" -e
$argon2i$v=19$m=4096,t=3,p=1$c2FsdHNhbHQ$DKlexoEJUoZTmkAAC3SaMWk30El9/RvVhlqGo6afIng

$ echo -n "secret" | argon2 "saltsaltsalt" -e
$argon2i$v=19$m=4096,t=3,p=1$c2FsdHNhbHRzYWx0$qOCkx9nMeFlaGOO4DUmPDgrlUbgMMuO9T1+vQCFuyzw

$ echo -n "secretsecret" | argon2 "saltsalt" -e
$argon2i$v=19$m=4096,t=3,p=1$c2FsdHNhbHQ$U0Pd/wEsssZ9bHezDA8oxHnWe01xftykEy+7ehM2vic

$ echo -n "secretsecret" | argon2 "saltsaltsalt" -e
$argon2i$v=19$m=4096,t=3,p=1$c2FsdHNhbHRzYWx0$fkvoOwKgVtlX9ZDqcHFyyArBvqnAM0Igca8SScB4Jsc



Alternatively we could modify an existing user's password with
ldappasswd, and then test binding as that user:

$ ldappasswd -D "cn=admin,dc=example,dc=com" -x -W -S uid=jturner,ou=People,dc=example,dc=com
New password: secret
Re-enter new password: secret
Enter LDAP Password: <cn=admin's password>

$ ldapsearch -b "dc=example,dc=com" -D "uid=jturner,ou=People,dc=example,dc=com" -x -w secret



---

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Copyright 2017-2026 The OpenLDAP Foundation.
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted only as authorized by the OpenLDAP
Public License.

A copy of this license is available in the file LICENSE in the
top-level directory of the distribution or, alternatively, at
<http://www.OpenLDAP.org/license.html>.

---
