Authenticate
Takes $password, $created and $nonce, and returns a boolean value representing whether the authentication succeeded.
If both $nonce and $created are specified, treat $password as:
md5_base64(md5_base64($real_password) . $created . $nonce)
and validate it, where $created is in unix timestamp format, and $nonce is a random string no longer than 32 bytes.
Otherwise, simply pass $password to IsPassword().