Re: Cracking decrypted file when knowing partial contents

From: Adfa (adfa_at_noname.com)
Date: 04/23/04 

Date: Fri, 23 Apr 2004 15:39:30 +1000

Can anyone then recommend a good application to encypt and decrypt files
(e.g. MS Word and text files) in Windows, preferably something that is fast
and easy to use for frequent opening and closing of files (e.g. can run in
the system tray with right-click context menus in Windows Explorer or
something)?

> Since as far as I know, nothing from Microsoft is open source, I would
> not trust any of them. Cryptography is not something whose strength can
> be determined from the output. It can only be determined by examining
> the code. Also, what is the world is RC4 doing there at all. RC4 is
> terrible as a symmetric cypher with user supplied key. While it can be
> fixed up with a random salt, it is still not what I would use for a
> symmetric cypher with user supplied key. It's one advantage is that it
> is fast. (I suppose they could also use a random key for the RC4 and
> encrypt that key with your favourite keyed cypher, which I think would
> be fine. Except that the program would have to make sure that it never
> reused the key, ie generated a fresh random key each and every time the
> file was encrypted-- no matter how small the change to the file. Again
> that is something that could be checked only if the source code were
> available.)

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