Guess again (and again and again: Measuring password strength by simulating password-cracking algorithms.   [PDF, BibTeX, ]
Patrick Gage Kelley, Saranga Komanduri, Michelle L. Mazurek, Rich Shay, Tim Vidas, Lujo Bauer, Nicolas Christin, Lorrie Faith Cranor, and Julio Lopez.
Technical Report CMU-CYLAB-11-008, CyLab, Carnegie Mellon University, August 2011.