August 4th, 2007, 10:39 PM
ok so i encode a file with blowfish on my computer and call it helloworld
if i try and open it with out the pass word by viewing it with notepad++ it churns out pages of chuzz
so lets say i print out those pages of chuzz
delete file on computer
then scan in pages of chuzz and save as helloworld
can i still unencrypt with blowfish?
basically can i make a hard copy of an encrypted file?
like life, this is a test
August 4th, 2007, 10:53 PM
When you scan the printed file you are creating some sort of image file. That will not be recognised by the encryption tool.
Yes you can make a hard copy of an encrypted file but being able to decrypt it will require you to reconstruct it in its original format.
EDIT: Your problem is compounded by the fact that you have also changed the file by opening it in notepad/wordpad.
I am sure that Federal Agencies would be able to do this without much difficulty (due to their resources) but it is not normal to save an encrypted file in such a way because it is meaningless?
Last edited by nihil; August 4th, 2007 at 11:04 PM.
August 5th, 2007, 09:15 AM
Sorry for jumping in, but I wonder if someone could clarify something for me. If the printed chuzz is scanned, is the OP using text recognition software to create a file or is it scanning, as in creating a jpeg, bmp etc.?
A related question (and I know that this would be an absolute PITA) - if I sat down with a hex editor, reproduced the chuzz and saved it as the original encrypted file (with the same extension), why couldn't that be decrypted? I know next to nothing about blowfish etc., so there might be something very obvious that I'm missing. For instance, I know that a MD5 hash can't be used to recreate the file that created it.
August 5th, 2007, 10:47 AM
As I understood the question, he has created a text file and printed it. When he scans this, it will create some sort of image file. That then leaves you with the task of converting it into a data file.
OCR software might be able to do this, but I wouldn't hold out any great hope as who would want to print an encrypted file in the first place and then recover it................. I really don't see a viable market for such software?
Sure, I have some software that will turn a scanned form into a live form, but it isn't 100% and requires some manipulation. That might be rather difficult with encrypted gibberish? For example, with my software you have to define the fields to it, and these need to be consistent on the scanned images.
Yes, the way I imagined it would be to use a hex editor and re-type the file. That should get us back to the .txt version
The next task is to convert that back to its original format. This might be as simple as changing the extension?
In theory, you should now have a copy of the original file.
If you use the same encryption application on the same computer it should (once again theoretically) be capable of being opened and read.
I would suggest that the actual encryption algorithm isn't particularly important compared to the encryption application and its logic and methodology.
I guess the only way to find out is to try it?
August 5th, 2007, 03:04 PM
when i find my scanner i will try it out and report back
but currently nursing my very sore back which i put out on wednesday, only just been able to go to do my ablutions on my own!!!!!!
like life, this is a test
August 6th, 2007, 09:28 AM
Thanks nihil - I appreciate the explanation. My concept of "image" (in this context) was correct. Maybe I'll have a try at this - but I'd want to find a very small executable, otherwise I'd be here typing into the hex editor until Christmas!
August 7th, 2007, 06:19 PM
well, OCR works better when you know the font and size of the text. Half the problem with OCR is that a ( in times new roman looks a lot like a c in arial. (Random made up example)
If the world doesn't stop annoying me I will name my kids ";DROP DATABASE;" and get revenge.
August 8th, 2007, 07:43 AM
You would need to have Notepad++ in Hex mode - if you have it in text mode you would not be able to discern all of the non-printable characters, and you would be unlikely to be able to reconstruct it from there.
Originally Posted by yellowcat
If you had it in Hex mode however, you would have the full values of every byte, so you could enter the data OK.
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