The given 'Tool' generates a random string (of a given specific length) from a given character set.
Such random string can be very desirable in many cases, especially, when trying to calculate a random 'key' of specific length (as in block ciphers).
warning: While using the 'Tool': length too big might 'crash' the browser or 'hang' your computer!!!
Use only for small tasks, like generating 'random' key of few characters (eg. 128 characters)
Next is the block cipher DES and its modes of operations.
Bye till then.