Re: encryption program question

On Tue, Feb 28, 2012 at 1:15 PM, John Smith <[email protected]> wrote:

>
>
> > Just to explain that a little more. If you only used keys that were
> > prime digits long you'd be pretty seriously constraining your keyspace
> > so the only thing you'd be really doing is making your system less
> > secure by knocking out a large swathe of potential keys.
> that's a good point John, I hadn't thought of that. Any thoughts on the
> relative security of encrypting a file several times over with different
> keys of different lengths and different complexities? I thought about
> building that functionality into this system just for fun (and to see if I
> can do it) Plus, this seems like it would make cracking the encryption
> through brute-force much harder. Also, my program does not seem to be
> subject to "patterns". For example if you had a file with two strings of
> say 5 'a's each, when you encrypted the file, each symbol in the encrypted
> file would be different, so cracking the encryption by looking for
> repeating symbols would be pretty hard.
>
>
Please, start with this: http://www.schneier.com/book-applied.html.
Honestly, inventing your own encryption is easy, inventing your own
encryption that you can't break is a little harder, inventing your own
encryption that cryptographers can't break is Really, Really Hard. That
doesn't mean it's not worth playing around with different schemes, making
you're own software based enigma engine and the like, but please don't
invent a new encryption method and use it in production code.

Sorry, I'll get off my soapbox. I'm not trying to be discouraging - if
you're interested in cryptography, there's a lot of useful information out
there, but some of it does require a *lot* of mathematical background. See
http://www.schneier.com/crypto-gram-9910.html#SoYouWanttobeaCryptographer

Good luck & have fun.
Herb.