No "Official" ranking as far as I know, however, a lot of password crackers use "known" lists or combinations, and different algorithms.....for a "Strong" password, use at LEAST 8 characters, with a mixture of uppercase and lower case letters and other AscII keys, a better length would be something easily remembered, but at least twelve or more characters long....the longer the password string, the longer it will take a cracker to break it...