MySQL password function

The docs for MySQL's PASSWORD() function states:

The PASSWORD() function is used by the authentication system in MySQL Server; you should not use it in your own applications.

Read "You're Probably Storing Passwords Incorrectly" for better advice on hashing and storing passwords.

MD5 and SHA-1 are considered to be too weak to use for passwords. The current recommendation is to use SHA-256.

I contributed a patch to MySQL to support a SHA2() function, and the patch was accepted, but since their roadmap has changed it's not clear when it will make it into a released product.

In the meantime, you can use hashing and salting in your programming language, and simply store the result hash digest in the database. If you use PHP, SHA-256 is available in the hash() function.

update: MySQL 5.5.8 was released in December 2010, and that release contains support for the SHA2() function.

If you are using a database function to hash passwords then by definition they have to arrive in the database unhashed: I would therefore prefer to do it much nearer the "source" i.e. in the frontend application so you're not passing around exposed information.