   OLD_PASSWORD(str)

OLD_PASSWORD() is available as of MySQL 4.1, when the implementation of
PASSWORD() was changed to improve security. OLD_PASSWORD()
returns the value of the pre-4.1 implementation of PASSWORD().
[Password hashing].

   PASSWORD(str)
Calculates and returns a password string from the plaintext password
str, or NULL if the argument was NULL. This is
the function that is used for encrypting MySQL passwords for storage
in the Password column of the user grant table.
