11. One or more tangible non-transitory computer-readable media having computer-executable instructions for performing a method of running a software program on a computing device, the computing device operating under an operating system, the method including issuing instructions from the software program for a computer processor to generate a probabilistic password cracking system for cracking a targeted password for a secured user account associated with a user, the instructions comprising: receiving a plurality of known password strings, said plurality of known password strings formed of at least one category selected from the group consisting of alpha strings, digits, and special characters; deriving one or more base structures from said plurality of known password strings, whereby one base structure may include more than one password string from said plurality of known password strings; detecting relevant patterns from said plurality of known password strings, wherein said relevant patterns include an A-word, an R-word, an R-pattern, an M-word, and an A-pattern; automatically assigning a set of probability values to each relevant pattern of said relevant patterns and to each base structure of said one or more base structures based on a probability value of each alpha string, each digit, or each special character in said each base structure; creating a probabilistic context free grammar based on said set of probability values assigned to said each relevant pattern to said each base structure; receiving one or more input dictionaries containing a plurality of sequences of alpha characters; generating password guess strings in decreasing estimated probability via said probabilistic context-free grammar by utilizing said plurality of sequences of alpha characters; accessing a login interface to the secured user account; and applying said password guess strings from said computer processor sequentially to said login interface, whereby authentication of the user can be achieved.
11. One or more tangible non-transitory computer-readable media having computer-executable instructions for performing a method of running a software program on a computing device, the computing device operating under an operating system, the method including issuing instructions from the software program for a computer processor to generate a probabilistic password cracking system for cracking a targeted password for a secured user account associated with a user, the instructions comprising: receiving a plurality of known password strings, said plurality of known password strings formed of at least one category selected from the group consisting of alpha strings, digits, and special characters; deriving one or more base structures from said plurality of known password strings, whereby one base structure may include more than one password string from said plurality of known password strings; detecting relevant patterns from said plurality of known password strings, wherein said relevant patterns include an A-word, an R-word, an R-pattern, an M-word, and an A-pattern; automatically assigning a set of probability values to each relevant pattern of said relevant patterns and to each base structure of said one or more base structures based on a probability value of each alpha string, each digit, or each special character in said each base structure; creating a probabilistic context free grammar based on said set of probability values assigned to said each relevant pattern to said each base structure; receiving one or more input dictionaries containing a plurality of sequences of alpha characters; generating password guess strings in decreasing estimated probability via said probabilistic context-free grammar by utilizing said plurality of sequences of alpha characters; accessing a login interface to the secured user account; and applying said password guess strings from said computer processor sequentially to said login interface, whereby authentication of the user can be achieved. 18. One or more tangible non-transitory computer-readable media as in claim 11 , further comprising: optimizing a primary dictionary of said one or more input dictionaries based on size and content of said primary dictionary; and assigning an additional probability value to said primary dictionary, wherein an effectiveness of said primary dictionary is measured by coverage and precision of said primary dictionary cracking said targeted password.