Passwords are generated from the ASCII 32-126 character set. These coincide with UTF8 characters. There are 95 characters in this set. In a 15-ch password this gives 95^15 permutations. A pass-phrase using just english nouns would need to be about 48 characters long to be as secure (asuming about 300,000 english nouns, with average length 7 characters). 

All the characters in this range can easily be entered via the keyboard, although it is expected that the strong password would only ever be deployed automatically using the "remember password" facility in your browser, or exceptionally using Copy+Paste from a master list of passwords held outside the browser. 

At least 1 of each type of character requested (ie Uppercase, Lowercase, Digit, Special - but not Space) will be included in the generated password. This is in line with a common restriction on passwords imposed by websites, although it reduces the overall number of permutations somewhat.

