Showing posts from May, 2009

Character Frequency Analysis Info

Sorry for the long delay between postings. Between the IEEE Security & Privacy conference and moving back up to D.C. for the summer my computer time has been limited. Well enough whining from me.  On to the data! With character frequency analysis, I normally divide it up into three sections, first letter analysis, last letter analysis and overall analysis, (I probably should do middle as well, but I've found it closely mirrors overall analysis). There are a couple of reasons for this distinction: 1) They do vary quite a bit.  People tend to capitalize the first letter much more often than any other letter. Also people tend to put numbers at the end of passwords. You get the idea. 2)While I like using Markov models, (they track the conditional probability of letters appearing together, for example if you have a 'q' the next letter will almost always be a 'u'), they can be a pain sometimes to set up. In that case using letter frequency analysis  greatly helps when