Patent ID: 8539247

Claim:
A computer-implemented method, comprising: receiving a proposed password; parsing the proposed password into two or more symbols, wherein a first symbol of the two or more symbols comprises one or more characters, and a second symbol of the two or more symbols comprises two or more characters; wherein the parsing the proposed password into two or more symbols comprises determining a number of characters for each symbol, and finding a longest possible matching symbol, from the two or more symbols, that matches a character string, from a plurality of character strings, in a database source; based at least in part on a sequence of the first and second symbols and the plurality of strings in the database source, determining one or more probabilities and storing in a first probability metric those probabilities from the one or more probabilities that exceed a threshold value and indicate not uncommon character strings; based at least in part on the first probability metric, determining whether the proposed password is secure; wherein the method is performed by one or more computing devices.