Tuesday, May 5, 2009

Using a JPG as hidden lockbox.

Found a very cool way to hide important files on your computer without using encryption or anything.

1. You put your file (i.e. online banking passwords or something) into a Rar archive (i.e. secret.rar).

2. Put a jpg image into the same directory (i.e. picture.jpg).

3. Open a command prompt and go to that directrory.

4. Now type 'copy /B picture.jpg + secret.rar picture.jpg'.

What you end up with is a file that looks and acts just like a jpg but the file size will be the sum of both files. To access to the Rar portion of this concatenated file you simply right click it and use the 'open with' option then choose WinRar and voila you can access your secret data. The only catch is, if you were to try to edit the jpg with a graphics application, you risk corrupting the Rar file it is attached to.


The Irascible Neufonzola said...

Note to self...when cracking into my old friend Percussite's personal computer in my future capacity as Evil Government Anti-Dissident Technologist Czar, write a small program to search the entire computer and order all *.jpg files by a computed ratio between pixel count (computed by the horizontal and vertical pixel count in the file metadata) and file size.

Percussivity said...

Of course that might work with bitmaps... but depending on the compression ratio I choose when saving the jpg to begin with the size could vary greatly.

A Pilgrim's Porridge said...

this is something that I do understand and Percuss is right.

with that said I would never utilize such a thing, I'm not sure what I have to hide? There has to be something, right?

The Irascible Neufonzola said...

I'm sure the jpeg compression ratios could be gleaned as well and incorporated into the formula...thanks for that [adds to notes]. It's certainly not perfect or absolute but it should save me more time than trying to open every jpg on disk with 7zip or winrar.

I as well have nothing that's really worth hiding.