Abstract or Summary:
In this paper we propose a new proactive password checker, a program which prevents the choice of easy-to-guess passwords. The checker uses a decision tree, constructed applying the Minimum Description Length Principle and a Pessimistic Pruning Technique. Experimental results show a substantial improvement in performance of this checker compared to previous proposals. Moreover, the whole software package we provide has a user-friendly interface, enabling the system administrator to configure an ad hoc password proactive checker, in order to satisfy certain policy requirements.