Re: Trying to find MS-DOS encryption utility



Hi Franc,

Thanks for your reply!

I haven't found any clues in the files at all but this is more or less as expected. It suggests that this was a very simple program and probably not very robust encryption-wise (but robust enough to cause me a problem :-).

It does exactly the same job on encrypted and non-encrypted files: It just uses the password for some manipulation of the data in the file and if the file was encrypted you get the non-encrypted file back. This suggests a very simple algorithm to me...

Willy


"Franc Zabkar" <fzabkar@xxxxxxxxxxxxxxxxx> wrote in message news:0kfsm4p5qp36h4epauqffnur4csrggsmbi@xxxxxxxxxx
On Wed, 14 Jan 2009 11:08:38 +0100, "Willy" <nospam@xxxxxxxxxx> put
finger to keyboard and composed:

Once upon a time I downloaded a simple encryption utility for MS-DOS. I'm
quite sure it was called cryptfile and all it did was encrypt a file with
the following command:

cryptfile <filename>

It then asked twice for the encryption password and would beep when
encryption was complete.

Encryption and decryption was exactly the same procedure, so if the file was
plain it would be encrypted and if it was encrypted it would be decrypted.

This suggests that the encrypted file must contain some signature that
distinguishes it from an unencrypted file, and presumably from files
encrypted by other software.

Are there any clues in the file headers?

- Franc Zabkar
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