This is a PHP implementation of the pbkdf2 key derivation algorithm from Defuse's Password Hashing [1] to use with the Drupal module pbkdf2_key_derivation [2].
Taylor Hornby (defuse.ca)
[1] https://github.com/defuse/password-hashing [2] https://www.drupal.org/project/pbkdf2_key_derivation