Joomla passwords are MD5 hashed, but the passwords are salted before being hashed.
They are stored in the database as {hash}:{salt} this salt is a random string 32 characters in length.

So to create a new password hash you would do md5($password.$salt)

EDIT

Okay so for checking a password, say a user myguy enters the password mypassword, you would retrieve the row from the database that has username myguy.

In this row you’ll find a password say 4e9e4bcc5752d6f939aedb42408fd3aa:0vURRbyY8Ea0tlvnTFn7xcKpjTFyn0YT.
You split up the password hash and the salt:

$hashparts = preg_split (':' , $dbpassword);
echo $hashparts[0]; //this is the hash  4e9e4bcc5752d6f939aedb42408fd3aa
echo $hashparts[1]; //this is the salt  0vURRbyY8Ea0tlvnTFn7xcKpjTFyn0YT

now calculate the hash using this salt and the password myguy entered

$userhash = md5($userpassword.$hashparts[1]); // This would be 'mypassword' and the salt used in the original hash

Now if this $userhash and $hashparts[0] are identical the user has entered the correct password.

From joomla Forum, that’s what happen behind:

A. Generate a password
B. Generate a string with 32 random characters
C. Concatenate Password (Step A) and RandomString (Step B)
D. Take md5(Result of Step C)
E. store Step D Result : Step B Result

Example:

Generate a password - Let 'testing'
Generate a string of 32 random characters - 'aNs1L5PajsIscupUskaNdPenustelsPe'
Concatenate Password and random string - testingaNs1L5PajsIscupUskaNdPenustelsPe
md5(Step C Result) - 5cf56p85sf15lpyf30c3fd19819p58ly
store step d:step B - 5cf56p85sf15lpyf30c3fd19819p58ly:aNs1L5PajsIscupUskaNdPenustelsPe

You can find code in Joomla like

$salt = JUserHelper::genRandomPassword(32);
$crypt = JUserHelper::getCryptedPassword("testing", $salt);
$password = $crypt . ':' . $salt;

Or We can Say

password DB field = md5(password + salt) + ":" + salt 

Where salt is random 32 char string.

thanks

In joomla standard you can create password using the following way

                     jimport('joomla.user.helper');
             $salt = JUserHelper::genRandomPassword(32);
             $crypt = JUserHelper::getCryptedPassword($password_choose, $salt);
             $password = $crypt.':'.$salt;

you mention that you are accessing from external file(or programs) then if you have joomla installation on other side you can access it from outside the joomla structure.

using joomla default frame work like this

define( '_JEXEC', 1 );
define('JPATH_BASE', dirname(__FILE__) );//this is when we are in the root
define( 'DS', DIRECTORY_SEPARATOR );

require_once ( JPATH_BASE .DS.'includes'.DS.'defines.php' );
require_once ( JPATH_BASE .DS.'includes'.DS.'framework.php' );

$mainframe =& JFactory::getApplication('site');
$mainframe->initialise();

I couldn’t use preg_split but explode works well.

$hashparts = explode (':' , $dbpassword);

From the joomla source file libraries/joomla/crypt/password/simple.php there are multiple ways they get stored, and some do not have a ‘:’ character.

    switch ($type)
    {
        case '$2a$':
        case JCryptPassword::BLOWFISH:
            if (JCrypt::hasStrongPasswordSupport())
            {
                $type = '$2y$';
            }
            else
            {
                $type = '$2a$';
            }

            $salt = $type . str_pad($this->cost, 2, '0', STR_PAD_LEFT) . '$' . $this->getSalt(22);

            return crypt($password, $salt);

        case JCryptPassword::MD5:
            $salt = $this->getSalt(12);

            $salt = '$1$' . $salt;

            return crypt($password, $salt);

        case JCryptPassword::JOOMLA:
            $salt = $this->getSalt(32);

            return md5($password . $salt) . ':' . $salt;


    }
}

Joomla! uses PhPass.

root/libraries/phpass/PasswordHash.php

have a look here. you will see here how the password is generating.

The $2y is the default (and preferred) prefix on bcrypt hashes.
As for code, you’ll want to look inside JUserHelper's hashPassword and verifyPassword methods to see how Joomla’s working with things right now.

Some Referances –

https://github.com/joomla/joomla-cms/blob/3.4.1/libraries/joomla/user/helper.php#L296-L387

https://docs.joomla.org/API15:JUserHelper/getCryptedPassword

https://docs.joomla.org/API15:JUserHelper/getSalt

Check the links, I hope you it will helpful 🙂

Joomla “understands” the passwords with “normal” md5.

What I’ve done in the past (to test a user’s login), was to save the original password, encrypt a new one in md5, replace it in the database, test it with the browser (and it works) and when I was done, paste the original password in the database.

If you just use md5($password); it’ll work, try it. Joomla has a mechanism and it can work with multiple types of passwords (including, as of late, strong passwords). You don’t have to worry about the part after the colon. Just use md5($password) and it’ll definitely work.

By the way, this’ll also work on Joomla 3.x.

<?php
$r = bin2hex(mcrypt_create_iv(16, MCRYPT_DEV_URANDOM));
$p = 'the_password';

$s = $p . $r;
$m = md5($s);

$out = $m . ':' . $r;
echo $out;

Len 16 because bin2hex doubles the character size, since 1 byte becomes 2 bytes