[junk]DeZCrypt

[DeZmond]

Well this is my long-awaited encryption program - I've been "working" on it for about 7 months so it's about time I actually showed you what it looks like.

So, it's a beta program, it stinks basically. I'm showing it because some people were curious as to what exactly it was I was coding for all this time. I don't recommend you use it other than to test the program's function.

It works on the simplest principle of cryptography, and as such, is, as I have previously stated, not particularly secure. Security through obscurity is a phrase that should spring to mind.

Source code available on request. (However it uses a different encryption key, so that the integrity of the original program is not lost.)

http://dezmond.thehavennet.org.uk/dezcrypt.zip

Minimum Requirements
Processor: Something post-Stone age should cope.
RAM: 32MB or more (oh the horror!)
HD Space: 20MB
Windows: any x86 version should suffice: however 95 is unsupported!!! (but may work).

For more info see the included manual.

 

[Pestcontrol]

Our dezmond a cryptographer, who'd have thought.

I like the splash and interface, it reminds me of those cracks you download to make your games work.

Also found a bug, when you save an encrypted file, the save dialog window says "save decrypted file".

Had a quick look at two simple encrypted and original files, they're the same length, so there's no header of any sort, and it appears to be a simple rotation type algo, 8 bit. It doesn't seem to do bit shift or simple additions/substractions with a single number, but at anything up to about 32 bit that's not a huge problem as you can just map it out and crack it that way.

 

[BiG D]

Far as I can tell, it outputs the ascii value + 101 of each character (using the iso-8859-1 charset)

 

[Pestcontrol]

You know i'd swear i got 107 for another character, maybe a typo.

 

[DeZmond]

:O - BiG D le h4x0r w00t!

Ahem... I mean, well done. Actually I can't remember the exact number it shifts it, but you've caught on quickly .

Also found a bug, when you save an encrypted file, the save dialog window says "save decrypted file".

Cheers, I hadn't spotted that. Chances are I've just called up the wrong dialog box, should be nice and easy to fix.

As I said, more a technology test than a proper program, I might just modify the algo to accept a user-input value (0-255) and that would make the functionality a bit better. But not a lot.

Yes I need to figure out a way to make a better algorithm that actually does proper addition/subtraction etc to make the thing actually *hard* to crack, however since the program currently works on the basis of this being reversible it means that it's not too difficult to crack. Maybe I should just shoehorn something like Rijandel and be done with it???

 

[Pestcontrol]

If it's a uni project about encryption, you'd have to come up with something more sophisticated. An 8 bit key is 72 bits short of being secure, and the key should be varied for each character in some pseudorandom way so you can't crack it by looking at it with a hex editor.

If it's a project for writing a program with an interface and dialog boxes, you're done.

 

[DeZmond]

It's not a project per se, just me messing about with coding. So don't worry, I'm not failing a programming course or anything. Because I've never been on one in my life.

 

[KillCrazy]

Yeah I'm on a programming course and he knows more than I do.

 

[Pestcontrol]

Then just toss rijndael in there, and include a hash (sha-256) of the source file in the result so you can detect tampering.

 

[DeZmond]

Okay, I've COMPLETELY redone DeZCrypt based on feedback here. Beta 2 is now available for testing - download as before. I've included a copy of Beta 1 in the zip, because Beta 2 is now incompatible with Beta 1. For reasons that will very soon become apparant .

I need to work on the user interface, and also strip out some of the more useless cyphers/hashes, among other things.

Open to feedback.

 

[Pestcontrol]

Oooh, spoilt for choice, i like, although not something i'd recommend to people who don't know the details.

Hmm, you could include DeZ8 as algorithm in dezcrypt2 for backwards compatibility, although i don't think there's a large amount of users with dez8 protected files.

I found a small bug, the file dialog button for the input file disappears after use. It's still there though and becomes visible again when clicked.

.... But i also found a larger bug. It decrypts corrupted files without any warning. I changed one character in the encrypted file and sure enough, one letter changed in the decrypted one. No warning or error from the program.

On the software ergonomics side, having to specify an output file is a bit cumbersome. Perhaps on opening a file, it should immidately give the output file dialog, with the filename already filled out with an extention appended. filename.ext.crp or something, so you don't normally have to do any typing, but can just click OK. I feel it's something that would become a point of annoyance for me when using DeZCrypt on a regular basis.

On the whole, good work, definitely benefits from the proffessional encryption algorithms available, some issues, but a good improvement.

 

[DeZmond]

Excellent, thank you for the full evaluation - this is why I ask your opinion on this type of thing!

I'll work through your suggestions, and some more besides, to see what I turn up with.