23.2.3.8. Password-Validation Plugins

As of MySQL 5.6.6, the server provides an interface for writing plugins that test passwords. Such a plugin implements two capabilities:

Rejection of too-weak passwords in statements that assign passwords (such as CREATE USER, GRANT, and SET PASSWORD statements), and passwords given as arguments to the PASSWORD() and OLD_PASSWORD() functions.
Assessing the strength of potential passwords for the VALIDATE_PASSWORD_STRENGTH() SQL function.