Abstract: System and methodology that utilizes keyboard patterns and alpha string patterns for password cracking. Keyboard patterns can be used as components of passwords, and the relevant shapes can extracted from these keyboard patterns and passwords. This keyboard information can be used to extend a probabilistic context-free grammar that can then be used to generate guesses containing keyboard patterns. Further, patterns in alpha strings, such as repeated words and multi-words, can be systematically learned using a training dictionary. This information can be used to extend the probabilistic context-free grammars which leads to generation of guesses based on the distribution of these patterns in the alpha strings, Keyboard patterns and alpha string patterns, individually and in combination, are shown herein to be effective for password cracking.