Nowadays, there are many web sites and e-business websites improve security level on authentication user or process business. They add one layer password security beside hashing password (like md5). It is known as Salt. Sort of view, salt is random 6-16 characters ( from 48 to 128 bits lengths).
This is how it works in PHP:
And this is how it’s combined with md5:
Now, you can store the hashPassword on your database, and REMEMBER to create salt field to store the $salt character too on that database so you can use it to process the password later.
Is this helpfull? Feel free to submit some comments..